extreme weather

NW Pacific Heatwave Attribution – Multiple Climate Model Failure

The authors describe the models used thus:

Model simulations from the 6th Coupled Model Intercomparison Project (CMIP6; Eyring et al., 2016) are assessed. We combine the historical simulations (1850 to 2015) with the Shared Socioeconomic Pathway (SSP) projections (O’Neill et al., 2016) for the years 2016 to 2100. Here, we only use data from SSP5-8.5, although the pathways are very similar to each other over the period 2015–2021. Models are excluded if they do not provide the relevant variables, do not run from 1850 to 2100, or include duplicate time steps or missing time steps. All available ensemble members are used. A total of 18 models (88 ensemble members), which fulfill these criteria and passed the validation tests (Section 4), are used.

SSP5-8.5 means Shared Socioeconomic Pathway 5 combined with RCP8.5, leading to 8.5W/m2 GHG forcing at the earth’s surface by 2100. It is a very extreme worst case emissions/atmospheric GHG concentration scenario, not at all realistic but, for the 5 years from 2016-2021, when it is used in the models, it doesn’t make that much difference from other more realistic scenarios. Where it does make a great deal of difference is in the assessment of how much more frequent such extreme heatwaves will be over the coming century, which the authors rely on to make the alarming claim that such events will happen every 5-10 years by 2100.

The authors used other models as well for simulating the historical period:

In addition to the CMIP6 simulations, the ensemble of extended historical simulations from the IPSL-CM6A-LR model is used (see Boucher et al., 2020 for a description of the model). It is composed of 32 members, following the CMIP6 protocol (Eyring et al., 2016) over the historical period (1850-2014) and extended until 2029 using all forcings from the SSP2-4.5 scenario, except for the ozone concentration which has been kept constant at its 2014 climatology (as it was not available at the time of performing the extensions). This ensemble is used to explore the influence of internal variability.

We also examine five ensemble members of the AMIP experiment (1871-2019) from the GFDL-AM2.5C360 (Yang et al. 2021, Chan et al. 2021), which consists of the atmosphere and land components of the FLOR model but with horizontal resolution doubled to 25 km for a potentially better representation of extreme events.

They describe the basic attribution procedure as follows:

As discussed in section 1.2, we analyse the annual maximum of daily maximum temperatures (TXx) averaged over 45°N-52°N, 119°W-123°W. Initially, we analyse reanalysis data and station data from sites with long records. Next, we analyse climate model output for the same metric. We follow the steps outlined in the WWA protocol for event attribution. The analysis steps include: (i) trend calculation from observations; (ii) model validation; (iii) multi-method multi-model attribution and (iv) synthesis of the attribution statement.

The first stage of the process above is known as ‘detection’, i.e. the detection of the event from observations. Observations are then compared to models to arrive at an attribution. Here is what the authors say about the detection:

The detection results, i.e., the comparison of the fit for 2021 and for a pre-industrial climate, show an increase in intensity of TXx of ΔT = 3.1 ºC (95% CI: 1.1 to 4.7 ºC) and a probability ratio PR of 350 (3.2 to ∞).

They then introduce the section on the multi-model attribution:

5 Multi-method multi-model attribution

This section shows probability ratios and change in intensity ΔT for models that pass the validation tests and also includes the values calculated from the fits to observations (Table 2). Results are given both for changes in current climate (1.2°C) compared to the past (pre-industrial conditions) and, when available, for a climate at +2˚C of global warming above pre-industrial climate compared with current climate. The results are visualized in Section 6.

Here are the results:

Note that the observed change intensity of the heatwave in the study area is 3.1C, according to observations (ERA5). The best estimate modelled change in intensity is anywhere between 0.22C and 2.6C, i.e. none of the models actually capture the observed change in intensity. The mean best estimate change in intensity of all the models is 1.77C, which is just 57% of the actual observed change. Thus, the models don’t come close to simulating actual reality. But again, this does not deter the authors from going ahead with an attribution anyway. They call it a hazard synthesis. I call it a hazardous synthesis!

6 Hazard synthesis


We calculate the probability ratio as well as the change in magnitude of the event in the observations and the models. We synthesise the models with the observations to give an overarching attribution statement (please see e.g. Kew et al. (2021) for details on the synthesis technique including how weighting is calculated for observations and for models).

Results for current vs past climate, i.e. for 1.2°C of global warming vs pre-industrial conditions (1850-1900), indicate an increase in intensity of about 2.0 ˚C (1.2 ˚C to 2.8 ˚C) and a PR of at least 150. Model results for additional future changes if global warming reaches 2°C indicate another increase in intensity of about 1.3 ˚C (0.8 ˚C to 1.7 ˚C) and a PR of at least 3, with a best estimate of 175. This means that an event like the current one, that is currently estimated to occur only once every 1000 years, would occur roughly every 5 to 10 years in that future world with 2°C of global warming.

So there you are. A highly dubious statistical analysis combined with an observation/model synthesis using models which all fail to capture the observed intensity of the actual event, which mysteriously translates into the statement that the NW Pacific heatwave would be ‘virtually impossible without climate change’ and furthermore that we can expect such intense heatwaves every 5 to 10 years by the end of the century if we don’t urgently reduce emissions. What a farce and an insult to proper science, but it did its job, i.e. generated alarming, but highly misleading headlines around the world re. the supposed irrefutable connection with this extreme weather event and man-made climate change.

Unraveling ‘Attribution’ Pseudoscience – No, the NW Pacific Heatwave Would NOT Have Been ‘Virtually Impossible’ Without Global Warming

This is what the media is claiming, this is what ‘scientists’ are claiming. This is what Matt McGrath at the BBC is claiming:

The searing heat that scorched western Canada and the US at the end of June was “virtually impossible” without climate change, say scientists.

In their study, the team of researchers says that the deadly heatwave was a one-in-a-1,000-year event.

But we can expect extreme events such as this to become more common as the world heats up due to climate change.

If humans hadn’t influenced the climate to the extent that they have, the event would have been 150 times less likely.

Scientists worry that global heating, largely as a result of burning fossil fuels, is now driving up temperatures faster than models predict.

I’m claiming BS, so let’s get straight to it. First of all, this analysis was not an analysis of a heatwave in the technical sense. According to the UK Met Office:

The World Meteorological Organization (WMO) has drafted guidelines on the definition and monitoring of extreme weather and climate events (WMO, 2018). The recommended definition of a heatwave is:

‘A period of marked unusual hot weather over a region persisting for at least three consecutive days during the warm period of the year based on local climatological conditions, with thermal conditions recorded above given thresholds.’In addition, the characterisation of events should consider the following aspects:

Magnitude: The departure from normal, reflecting the climatological extremity of the event.

Duration: Measuring the duration of elevated temperatures.

Extent: The geographical extent of the heatwave.

Severity: Indicating potential damages and impacts of the event.

The NW Pacific heatwave might (just) have qualified on this basis as it occurred over a large region from the 27th to 29th June, but the authors of the WWA attribution analysis have chosen instead to concentrate not on the 3-day consecutive temperatures (including the all important minimum overnight temperatures) but just on the maximum daily one day annual temperature:

Note the highlighted text. In order to get the attribution out fast (whilst the event was still fresh in the minds of the public and presumably to get maximum media attention), they chose to concentrate only on the headline maximum temperatures, which gained most attention in the press. It would have been a more complex and lengthy analysis to concentrate on 3-day temperatures consistent with the actual WMO definition of a heatwave. Also, they deliberately limited their analysis to urban areas, excluding those wild regions where the daily maximum temperatures might not have been expected to be so extreme on account of the well documented and studied urban heat island effect. Indeed, two of their chosen station locations were situated at airports serving large cities; you know, those great slabs of concrete and tarmac, flat as a pancake, where huge jets with big engines are taking off and landing daily.

Temperature observations were collected to directly assess the probability ratios and return periods associated with the event for the three major cities in the study area; Portland, Seattle, and Vancouver. Observing sites were chosen that had long homogenized historical records and were representative of the severity of the event by avoiding exposure to nearby large water bodies. Sites were also chosen to be representative of the populous areas of each city to better illuminate impact on inhabitants. For Portland, the Portland International Airport National Weather Service station was used, which has continuous observations over 1938–2021. The airport is located close to the city centre, adjacent to the Columbia River. The river’s influence is thought to be small and the water temperature is warm by June. For Seattle, Seattle-Tacoma International Airport was chosen, which has almost continuous observations 1948–2021, among the longest records in the Seattle area.

It’s odd, is it not, how they are at pains to avoid large bodies of water which might have a cooling effect, but they’re OK with choosing stations located in the middle of bloody great stretches of heat absorbing concrete and tarmac! Here’s what the cartoonist Josh has to say about that:

I’ve pointed out recently how the choice of event definition can affect the outcome of the attribution, by WWA’s own admission:

Addendum: Event definition

WWA have an article entitled ‘Pathways and Pitfalls in extreme event attribution’. They point out that the definition of the extreme event is very important in determining the result of the attribution. Defining the event is very much a choice of the people doing the analysis.

It’s almost certain that WWA will choose to define this extreme event only with reference to extreme daytime temperatures in the regional Pacific Northwest.

Was I right?

Here is the area studied:

To get an idea of just how extreme the departures were from the long term average in this study area, just look at this graph produced by the authors:

The red line is the maximum recorded temperature in any given year. The green line is the running 10 year average. Note that the series only covers from the period from 1950 (71 years). The green line is representative of the generalised warming in the study region with reference to maximum summer temperatures. As you can see, it’s of the order of 2 or 3 degrees C over the 70 year period to 2020, with annual departures from the trend line (positive or negative) amounting to no more than 4 degrees, the largest departures being negative values in the 1960s and 1970s. Then we get to 2021 and the red line jumps up 6 or even 7 degrees above the baseline! That’s huge. It just cannot be related to the observed slightly increasing long term trend. It can’t. Something else has to be in play, be it a ‘black swan’ extremely low probability event generated randomly or be it due to some very specific meteorological set up (perhaps amplified by other factors, e.g. land use, previous drought conditions), unique in the observed period.

But this does not stop the intrepid team at WWA from torturing the data to fit an extremely dubious statistical distribution. Yes, they actually squeeze this glaringly unusual and extreme departure from normal into a new statistical time series and by so doing they arrive at a highly improbable estimation of the return time for such an extreme event purportedly based upon this statistical time series. I’m actually gobsmacked. They own up to their sins in the paper, which is at least honest, but of course the media coverage (with the assent and cooperation of the authors themselves) is exceptionally dishonest, conveying the impression that this ‘scientific’ study revealed a strong link between this event and global warming.

So, as opposed to simply excluding the anomalous 2021 from the statistical analysis, they decided to try and provisionally include it, using an alternative approach, but this still didn’t give the ‘right’ answer because it implied that the event was either a ‘black swan’ with a return time of 10,000 years, even in the current climate, or that it was due to non-linear (i.e. dynamical/meteorological) effects which are not fully understood. Having to wait 10,000 years for another similar event is just not scary enough! So, the authors did this instead:

They deliberately chose an area where the heat was particularly extreme and they shoe-horned this extreme event to fit a highly improbably statistical series to arrive at a highly improbable estimate of a return time. Now, even a thousand years doesn’t sound that scary, but with projected global warming of another two degrees in 20 years time, which ‘could happen’, we could then be seeing a heatwave like this every 5 or 10 years. Friederike Otto, one of the paper’s authors, explains:

Co-author Dr Friederike Otto, from the University of Oxford, explained what the researchers meant when they said the extreme heat was “virtually impossible” without climate change.

“Without the additional greenhouse gases in the atmosphere, in the statistics that we have available with our models, and also the statistical models based on observations, such an event just does not occur,” she explained.

“Or if an event like this occurs, it occurs once in a million times, which is the statistical equivalent of never,” she told a news briefing.

This type of research, which seeks to determine the contribution of human-induced climate change to extreme weather events, is known as an attribution study.

According to the analysis, if the world warms by 2C, which could happen in about 20 years’ time, then the chances of having a heatwave similar to last week’s drop from around once every 1,000 years to roughly once every 5-10 years.

OMG, hit the panic button! We’re all gonna fry in 45C plus heatwaves if we don’t stop driving cars and get rid of our gas boilers and pay 10 times what we pay now for electricity which is produced exclusively by sustainable ‘sea breezes’ and food-crop-destroying arrays of solar panels. You see we don’t really need to travel, heat or eat, cheaply; what we do need to do is to save the damned planet from Thermageddon – and fast!

I was going to go through the entire paper in one go, exposing the bad science, bit by excruciating bit, but this is enough for now. I’ll write another post (or two) in the next day (or two)

#Rep 4 – One Day Heatwave at Cambridge Botanical Gardens Made 20 Times More Likely By Climate Change, Experts Say

Posted on  by Jaime JessopIn UK Met OfficeUncategorized9 Minutes Read

I’ve already covered the attribution study recently rushed out by scientists with regard to the very hot spell of weather in June. Now most of those same scientists have published a second attribution study which focuses on the 3 or 4 very hot days in northern France and Europe and the one very hot day in the UK on July 25th. Are we going to get a ‘It was climate change wot dunnit’ attribution study every time it gets hot in summer now? Looks like it.

As usual, the global media have given maximum coverage to this additional study which supposedly demonstrates that man-made global warming had its grubby fingerprints all over the second record breaking heatwave in Europe this summer. It’s as bad as, if not worse, than the original study and of course the headline claims that climate change made Europe’s July heat wave up to 3 degrees Celsius hotter, that the heat in France and Holland was made up to 100 times more likely and that in Cambridge up to 20 times more likely is pure hype.

Atmospheric blocking caused the July heatwave, just as in June

The authors say:

In a relatively similar way to the June case, the July heat wave occurred due to a ridge across western Europe (highly amplified Rossby wave), together with a low-pressure system developing offshore the Iberian peninsula, as shown in Figure 2. This weather pattern induced intense advection of hot air from North Western Africa across Spain to France (Figure 3) and then Germany and the Benelux, eventually reaching Scandinavia a few days later. In contrast to the June heatwave, this July heatwave was accompanied by severe drought conditions in areas such as France (a majority of French territory was under drought regulation measures), which might have been a confounding factor given that dry soils are suspected to cause an additional temperature increase at regional scales due to land-atmosphere feedbacks (Seneviratne et al., 2010).

So, once again, atmospheric dynamics play a significant role in directly causing the intense heat, just as we have seen they did in 2003 and 1947, although for summer 2019, the ‘heatwaves’ have been of very much shorter duration and I can find no reports of fatalities due to heat exhaustion for that very reason.

The attribution analysis was not done for Europe: it was done using average data from France only plus five individual weather stations in France, Holland, UK and Germany

Despite headline claims that this attribution study was about heatwaves in Europe and how they have been made much more likely by man-made climate change, it was not. The claim is incorrect and highly misleading. The results of this attribution apply strictly to just five individual weather stations, plus to metropolitan France in general but, as we will see the models were pretty useless for diagnosing trends throughout France and only moderately acceptable as diagnostic tools for the individual weather stations. But it gets worse, and worse again. Firstly, here is a list of the locations:

The only country wide data, which is for France only, is the France Metropolitan Average, which only goes back as far as 1950. Therefore it doesn’t even include data from the 1947 heatwave, not to mention any other heatwaves which might have occurred in the early part of the 20th century or even further back in the 19th century. So they’re doing an attribution analysis for France based on data from the modern period only using models which are biased to produce strong warming in the modern period and amazingly they find that man-made climate change had a significant impact! Only in climate science could this be justified. Any other field and it would be laughed out of the lab.

Only in climate science would scientists select five individual locations (weather stations each encompassing a microclimate of no more than a few hundreds of square meters) and perform a supposedly ‘rigorous’ attribution analysis, then plug their findings in the media as being somehow representative of the climate of an entire continent! It gets worse though; they didn’t just pick the stations, they cherry-picked them – outrageously cherry-picked them!

The rest of the analysis is based on a set of 5 individual weather stations. We selected the stations based on the availability of data, their series length (at least starting in 1951) and avoidance of urban heat island (UHI) and Irrigation Cooling Effects (ICE), which result in non-climatic trends. The locations considered all witnessed a historical record both in daily maximum and in 3-day mean temperature (apart from Oxford and Weilerswist-Lommersum where only daily maximum temperatures set a record).

The weather stations were deliberately selected because they set record high maximum temperatures, three of them also in 3 day mean temperature, which period was coincidentally also the basis for the event attribution, seeing as the ‘heatwave’ was so damned short it was over before it almost began! The choice of Cambridge Botanical gardens is even more hilarious because, as we have seen, the UK failed to live up to the Met Office’s hype and break the national all time temperature record of 38.5C. Then Cambridge University popped up and said that their botanical gardens managed 38.7C, so the Met office jumped at the opportunity to save face and they subsequently legitimised the ‘new record’ by ‘rigorously checking it for quality control’. LOL.

This was only a few days ago. The study’s authors must have then immediately leapt at the opportunity to include Cambridge Botanical Gardens in their ‘European Heatwave Attribution Study’ and stayed up all night presumably number-crunching the data from the station to ‘prove’ beyond all doubt that climate change must have come to Cambridge BG that day! I suspect this might be why there are two stations included in the study from the UK. But it gets even worse! They chose the station simply because the Met Office belatedly declared it as setting a new national maximum temperature record – despite its apparent unsuitability as pointed out by Paul Homewood. They also chose it knowing full well that the historic data was – shall we say – less than reliable:

The Cambridge Botanical Gardens (BG) station that observed the UK record temperature of 38.7 ºC has a sizeable fraction of missing dataOn 23 July there were battery issues, this value has been estimated by the UK Met Office on the basis of their interpolation routine. For earlier years we used the values of the nearby Cambridge NIAB station with a linear bias regression T(BG) = (1+A) T(NIAB) + B, with A about 5% in summer and B -0.6 ºC in July, -0.9 ºC in August.

Can I believe what I just read? On one of the days specifically included in their event definition (July 23rd), the thermometer batteries were on the blink so the Met Office had to estimate the data for that day and the authors used a nearby station to fill in the gaps for the large chunks of historic data (going back to 1911) missing from the station! All this, just so they could include the Botanical Gardens in their study, simply because it was the site of a decidedly dodgy UK all-time maximum temperature record! If that is not an ideologically driven choice by supposedly diligent, cautious, rational, and above all unbiased scientists, I don’t know what is. But there’s more! This is the study which just keeps giving.

Like the June study, the models are crap but in this case not crap enough – simply because of the choice of locations

Figure 5 compares the GEV distribution parameters between model ensembles and observations. In general, the same conclusions hold regarding models skill as in our analysis of the June heatwave [i.e. the models are crap at simulating the actual observations]. Models have a too high variability and hence overestimate the sigma parameter, sometimes by a large amount (factor 1.5 to 2.5). This is particularly marked for the France average. However, HadGEM3-A, EC-EARTH, IPSL-CM6-LR and CNRM-CM6.1 appear to have a reasonable departure from observations. For the other models the 95% confidence intervals on the scale parameter does not overlap with the confidence interval on the scale parameter from the observations, which is our criterion for inclusion of the models in the attribution.

Note that the models perform worse when it comes to the whole of France observations, i.e. the data over a much wider area. For the individual cherry-picked stations, they perform OK (just).

For individual stations studied here shape parameters are well simulated. The discrepancy for the scale parameter is also reduced except for weather@home where variability remains too high. The difference in behavior between the France average and the stations could arise from several reasons and remains to be investigated.

The issue requires an in-depth investigation, but probable reasons may be in a difficulty of models to correctly simulate land-atmosphere interactions, resulting in a deficit of skill for the simulation of heatwaves especially in regions where evapotranspiration regimes undergo transitions from energy-limited to soil-moisture limited regimes. Preliminary investigations into the deficits of weather@home have shown that an insufficient cloud cover in the model leads to unrealistically high hot extremes and low cold extremes. Another possible cause is dynamical as France may occasionally be influenced by episodic advection of hot and dry air from Spain and North Africa leading to large excursions of temperature which models might not capture well.

Yep, blah, blah, blah, etc. etc. Finally they get to the probable real reason why there’s a difference in model performance between individual stations and whole regions – a flipping great plume of hot air from Africa caused the heatwave and made it much more likely that very hot temperatures would be experienced on said days of the heatwave! They already bloody said this is what caused the extreme temperatures!

The source of the unusual heat was North Africa, scientists say, drawn up to Europe because of high pressure to the east of the UK.

[https://thefinancialanalyst.net/2019/08/02/climate-change-made-europes-2019-record-heatwave-up-to-100-times-more-likely/]

It’s one reason why it got very hot, up to 3.5C hotter than when it last got very hot, in 2003 and 1947. Other reasons include land use, urbanisation, station siting and yes, a general long term warming trend observed in the average temperatures of European summers. But what do our intrepid ‘scientists’ do? They use models which barely fit observations and they hype their own findings by falsely informing the public that the whole of the increase in record daily max temperatures can be attributed to man-made climate change. They also tell us that man-made climate change has made it up 100 times more likely that these extremes will occur!

Geert Jan van Oldenborgh (KNMI), one of the study’s authors admits all this to Carbon Brief, but the alarmist headlines remain and none of the scientists involved seem concerned in the least about the impression given to the public, even reinforcing that impression themselves in their press interviews.

As part of the analysis, the authors also looked at how extreme the temperatures seen during the July heatwave were in comparison to those seen in the past.

The authors find that the temperatures seen during this heatwave were around 3C higher than they would have been in 1900.

This is double the heatwave temperature increase expected by climate models – which are used to make projections about future climate change, van Oldernborgh says:

The models only predict that heatwaves get warmer at about 1.5C per degree of global warming. So for every degree of global warming, they predict that heatwaves get 1.5C hotter – a little bit faster but not really exceptional.”

The world has seen around 1C of global warming so far – meaning that the models would expect heatwaves to be around 1.5C hotter today than in pre-industrial times. However, temperatures during this heatwave were actually around 3C warmer, he says:

“We really need to do a lot more serious research than we can do within one week to look at why there is such a big discrepancy between the observed trends and the modelled trends. [No. Shit. Sherlock]

“But heatwaves are very special. A lot of things come together for a heatwave – heat from the Sahara, local heating due to sunshine, the reaction of vegetation due to very hot conditions – and all these things have to be modelled right. I’m just afraid that these models that have been designed to project the average climate correctly cannot handle these very extreme situations very well.”

So what have we learnt? We’ve learned that models are rubbish at analysing the human fingerprint in extreme weather events, but that scientists still use them and express over-confidently their opinions about how climate change has significantly altered the frequency and intensity of extreme heatwaves, using those models, combined with sparse data, poor data and unsuitable data. These opinions then get relayed to the media as ‘fact’ and idiot climate activists, Greens and lefty politicians double down on ‘climate crisis deniers’ as these ‘facts’ accumulate in the public arena.

#Rep 3 – 1947: An Anti-Hysterical Perspective On Modern European Heatwaves

2003. 2018 and now 2019: very hot (record-breakingly hot) conditions affect parts of central and northern Europe, with 2003 being by far the most significant and prolonged event. Cue, climate change hysteria from the warmist media, whacko climate crisis obsessed eco-loonies and AGW-biased scientists in search of research grants, prestige and a ‘noble cause’ for which to promote urgent action. As usual though, history often tells a less sensational tale, providing perspective on the current ‘end of the world’ narrative being perpetuated by the MSM and by emotionally and psychologically damaged members of the climate change end times Twitterati. You think I’m exaggerating? I’m not.

As it happened, 25th July 2019 wasn’t the day Britain transitioned to a ‘new climate’, because the temperature record of 38.5C set in the ‘old climate’ back in 2003 was not broken (except by iffy thermometers in Cambridge Uni’s Botanical gardens, that is). But you know how it is, Little England, being the backward, rain-soaked, cake-filled, cloud-bolted little island of grey skies, xenophobes and racists that it is, can’t be expected to immediately join continental Europe in heralding the terrifying arrival of the ‘new normal’. Germany, Belgium, Netherlands and Paris all transitioned on July 25th. Boris might make matters even worse on Halloween if he takes us ‘out of Europe’ without a deal, then God only knows how long it will be before climate alarmists can say that Britain is definitely CCBAR (climate changed beyond all recognition).

July 25th, though it didn’t see the UK transition from a benign climate to something much, much more horrible, did witness a significant rift open up between different factions of the Green blob: i.e. the opportunist BBC – who’ve bought in to the climate crisis purely for ideological reasons, and because they’re rabid, globalist lefties anyway – and those nutters who genuinely believe that we are all going to die in a few years time. The latter got quite upset at those caught ‘celebrating’ the imminent ‘hottest day evah’ in Britain. They were celebrating for the simple reason that it reinforced their catastrophe narrative. The ‘serious’ fanatics really do believe that a few very hot days are a prelude to the end of the world and they really do believe that the Beeb was being outrageously flippant. It’s quite comical.

Environmentalists who criticised the BBC for tweeting enthusiastically about the ongoing heatwave have been mocked online for their hysterical reaction. 

Campaigners including the Green Party and charity WWF heaped scorn upon the Corporation for the lighthearted tone it used when reporting the heatwave on social media.

As it happens, both factions were to be bitterly disappointed. The Met Office and the BBC didn’t get to crack open the chilled Champers and the eco-loons at GreenPiss, the Green Party, XR and WWF – plus the rest of the doom-filled Thermageddon-fixated adorers of Saint Greta – didn’t get to be really, really miserable. Shame. Never mind.

But anyway, enough of the entertainment; let’s get to the boring, ‘sciency’, fact-orientated bit. Why isn’t a few extremely hot days in Europe this year proof of a climate crisis?

The 1947 heatwave was more severe in Central Europe than 2003

In 2013, scientists from the Oeschger Centre for Climate Change Research and Institute of Geography, University of Bern, Switzerland analysed the heatwaves in Switzerland during 1947 using Meteo-Swiss weather records and the 20th Century Reanalysis (20CR) dataset based on NCEP. Here is what they found:

The heatwaves of 1947 can be compared with the events of 2003 in terms of intensity and duration.

The meteorological situation was characterized by a high-pressure bridge over Central Europe.

This report focuses on the heat period of 1947 in Switzerland. The summer of 1947 marked the culmination of a prolonged drought period that affected central Europe from around 1945 to the early 1950s.

The authors make it clear that it was atmospheric dynamics (circulation patterns/blocking high) which primarily caused the heatwave – just like in 2003, 2018 and now 2019.

The variability of air temperature in general and of extreme temperature events in particular is governed by atmospheric circulation. In particular, persistent high-pressure systems and associated circulation patterns may lead to positive anomalies of surface air temperature affecting a large area over prolonged time periods (Kysely and Huth, 2008). Heatwaves are often caused by quasi-stationary anticyclonic circulation anomalies or atmospheric blocking, which may be sustained or amplified by land-atmosphere feedbacks (IPCC, 2012). This is also the case for the region under study (Rüttimann et al., 2009).

Here are the anomalies over Europe in 1947 for Apr-Jun (left) and Jul-Sep (right) (Hadcrut 3) with respect to 1981-2010. You can see the heatwave was firmly centred over Central Western Europe and covered a huge area way beyond Switzerland, which country was not even at the epicentre.

In the analysis of the maximum temperature from the 14 meteorological stations, 29 July was the hottest day during summer 1947. The mean maximum temperature from all lowland (<560 m a.s.l.) stations on this date was 36.1 °C; 26.4 °C were reached at 2502 m a.s.l. In Basel 38.7 °C were measured – the highest recorded temperature during the heat period of 1947 and the highest temperature ever observed in Switzerland until 2003 (note, however, that the Wild screen used at that time in Basel was sensitive to radiation errors, see Auchmann and Brönnimann, 2012).

The heat period of 1947 can be compared with the year 2003 in terms of maximum temperatures and duration of the heatwaves. For instance, the maximum temperature anomaly, computed as departures from the 1961-1990 average, of the year 1947 amounted to 5 °C. This is only 1 °C less than for the year 2003. Another aspect is that in Basel, the threshold of 30 °C was exceeded 49 times in 1947, more often than in 2003 (41 times). 

The period of consecutive days during which the maximum temperature exceeded the 90% quantile of the summer temperature was also longer in 1947 than in 2003. During the year 1947 the longest heatwave lasted 14 days from 22 July to 4 August, whereas in 2003 only twelve consecutive heat days were recorded at the beginning of August (Z’Graggen, 2006; Beniston, 2004).

The meteorological situation during the heatwave event in 1947 analysed with the 20CR dataset shows typical features of a heatwave. The stationary high pressure system over the study region – the Central-European High – during the episode from the 22 July to 4 August 1947 is conductive for a heatwave according to Kysely and Huth (2008).

The analysis of the heatwaves in 1947 indicates that the event is comparable to 21stcentury heat periods such as the summer 2003 and that 1947 was extraordinary.

Even if the heatwave 2003 exceeded the maximum temperatures measured in 1947, in terms of the length of a heatwave and the exceedance of the 30 °C temperature threshold, the heat period 1947 was more intense.

So it’s fairly clear that:

  • 1947 was comparable to 2003 and both heatwaves were caused by very similar meteorological patterns.
  • 1947 maximum average temperatures were just 1C less than 2003
  • In terms of duration and number of days above 30C, 1947 was more intense

Given that summers in Europe have warmed significantly since 1950, it is perhaps not surprising that the daily average maximum temperature in 2003 exceeded that in 1947, but that’s the only real difference and by all other metrics, 1947 was more intense. Not forgetting also that urbanisation has increased since 1947 and land use has changed considerably, either of which may have contributed to generally higher temperatures. So, if you’re looking for the climate change signal in the heatwave of 2003, the increase in mean maximum temperature anomaly of 1C is it. Scary (not). Climate crisis (not). But Peter Stott et al say different:

Dramatically increasing chance of extremely hot summers since the 2003 European heatwave

A study by Christidis, Jones and Stott published Dec 2014 claims:

The vulnerability of European citizens was made evident during the summer heatwave of 2003 (refs 34) when the heat-related death toll ran into tens of thousands5Human influence at least doubled the chances of the event according to the first formal event attribution study6, which also made the ominous forecast that severe heatwaves could become commonplace by the 2040s. Here we investigate how the likelihood of having another extremely hot summer in one of the worst affected parts of Europe has changed ten years after the original study was published, given an observed summer temperature increase of 0.81 K since then.

Using a previously employed temperature threshold to define extremely hot summers, we find that events that would occur twice a century in the early 2000s are now expected to occur twice a decade. For the more extreme threshold observed in 2003, the return time reduces from thousands of years in the late twentieth century to about a hundred years in little over a decade.

Note the emphasis is on frequency of recurrence. Stott’s original attribution study of the 2003 heatwave categorised the event as:

 . . . . . probably the hottest in Europe since at latest ad 1500

Thereby classing it as a millennial scale event. However, we’ve just seen that 1947 was comparable to 2003 and only 1C cooler in terms of mean absolute maximum temperature. Also, the summer of 1541 was likely hotter, drier and far more intense than even 1947 or 2003. Stott paints the 2003 heatwave as some momentous event in the history of European weather and claims that, because of man-made climate change, such events are going to be ‘the new normal’ by the end of the 21st century. Stott is wrong about the uniqueness of 2003 in modern European meteorological history. 1947 was worse. 1976 was definitely worse – in the UK at least.

We’ve seen two heatwaves in Europe in 2018 and 2019, of similar intensity to 2003, but of shorter duration and impact (especially so far in 2019), with the 2018 heatwave being centred more over Scandinavia, the UK and Ireland – similar to 1976. Also, very inconveniently, many areas of Europe and Russia have experienced record summer minimum temperatures in 2019, whilst other parts were baking, but you didn’t hear about that in the media. But even so, perhaps Stotty is right about the increased probability of European heatwaves? Maybe they are becoming hotter and a lot more frequent due to man-made climate change? The climate fanatics certainly think so. To investigate this possibility though, we have to look at atmospheric dynamics, not just simple thermodynamics and, as it turns out, the answer is not that simple. Science and observations get in the way of warmist hyperbole. Bummer.

Observed 21st Century Increase of Jet Stream Blocking Events

study published in April this year states:

The summer of 2018 witnessed a number of extreme weather events such as heatwaves in North America, Western Europe and the Caspian Sea region, and rainfall extremes in South-East Europe and Japan that occurred near-simultaneously. Here we show that some of these extremes were connected by an amplified hemisphere-wide wavenumber 7 circulation pattern. We show that this pattern constitutes an important teleconnection in Northern Hemisphere summer associated with prolonged and above-normal temperatures in North America, Western Europe and the Caspian Sea region. This pattern was also observed during the European heatwaves of 2003, 2006 and 2015 among others. We show that the occurrence of this wave 7 pattern has increased over recent decades.

So what exactly has happened and can what has happened be attributed to anthropogenic influence?

Over recent decades the number of phase-locked wave-7 events (here defined as weeks with above average wave-7 amplitude within its preferred position, see figure S4) have increased significantly (95% confidence interval, figure 4(b)). Prior to 1999 there were no summers with two or more consecutive weeks of a wave 7 phase-locked circulation, but since then these have occurred (table S2). Thus, the persistence of such situations appears to have increased. In fact, the average duration has doubled from about one to two weeks per year, while the number of years with more than two events per summer shows an almost eight-fold increase (figure S7). Although the trends are always upward, i.e. independent of the amplitude threshold used, their significance is sensitive to the amplitude threshold due to the reduction in ensemble size for high amplitudes (figure 4(b)). The number of wave-7 events (i.e. weeks with a high-amplitude wave-7 irrespective of its phase position) do not show statistically significant upward trends for different thresholds used (figure 4(a)). A statistically significant upward trend in the observed amplitude of summertime wave-7 is only detected when data from the pre-satellite period is included (figure S8). The more pronounced trends in phase-locked events (figure 4(b)), compared to high-amplitude events (figure 4(a)) suggests that it is the phase-locking itself that has increasedIn general, these trends can simply reflect multi-decadal variability in the Earth system given that the satellite record is relatively shortNevertheless, an enhanced land-ocean temperature contrast as a consequence of amplified land warming provides a physical mechanism for such waves to become preferentially phase-locked. Such temperature contrast creates an increased zonal temperature gradient at the coastlines and provide a stationary vorticity source that triggers and maintains atmospheric waves [3031]. It is therefore possible that the relative position of land and ocean areas in the mid-latitudes with high values of dT/dx over the continental West-coasts could favor a hemispheric wave 7 pattern [32]. Such contrast would further be enhanced by the cooling trend of northern Atlantic sea surface temperatures linked to a slowdown of the Atlantic Meridional Overturning Circulation [33] and implicated in past European heat extremes [23] but this needs further investigation.

So, what the authors are saying here is that there is no trend in wave 7 phase locking events which would give rise to particularly hot summers in western Europe over the period of satellite observation, but that there is a very significant increase in phase locking events after 1999, which has resulted in a number of hot summers in Europe, including the very hot summer of 2003 and the memorable hot dry early summer of 2018 in north western Europe. What they say is that natural multidecadal variability may be the cause behind this change but that it’s plausible it may be due to Arctic warming, which implies anthropogenic causes (though note that this is only the case if such warming is attributable largely to anthropogenic causes).

Take home message: no increase in blocking over the period of satellite observations, only a 21st century increase which may be due to natural causes or possibly anthropogenic influence. More research needed.

1947 was a circulation-induced heatwave analogous to modern heatwaves

An interesting new study looking at 1947 as an analogue of more recent European heatwaves was published in May this year and Friederike Otto is among the authors. It’s rather better science, I must say, than the shockingly poor event attribution which was plugged by the media as ‘proof’ that the recent record breaking heatwave in France was man-made, which she also co-authored. The abstract says:

The science of extreme event attribution has rapidly expanded in recent years, with numerous studies dedicated to determining whether and to what extent anthropogenic climate change has increased the likelihood of specific extreme weather events occurring. However, the majority of such studies have focussed on extreme events which have occurred in the recent past (usually within the past 10 years) while minimal research efforts have considered the multitude of high-impact extreme climatic events which occurred throughout the instrumental record.

Using a reanalysis-based dataset, our results show changes in the frequency of 1947-like extreme heat throughout the twentieth century to be highly sensitive to methodological choices, particularly in the context of disaggregating dynamic and thermodynamic changes in the risk of extreme heat. Evidence also suggests clear decadal variability in the occurrence of circulation patterns conducive to the 1947 heatwaves.

The authors make the clear distinction between dynamic and thermodynamic influences when considering attribution of extreme events like European heatwaves:

Since European heatwaves are known to preferentially occur in the presence of specific summertime atmospheric circulation states (Cassou et al. 2005; Pfahl and Wernli 2012; Sousa et al. 2018; Jézéquel et al. 2018b), it is important to understand how dynamic and non-dynamic processes leading to heatwaves are each affected by anthropogenic climate change. Consequently, a second topic of recent research for the attribution community has concerned the extent to which changes in the likelihood of a particular extreme event occurring can be further separated into dynamic and thermodynamic contributions (Trenberth et al. 2015; Shepherd 2016; Otto et al. 2016; Harrington 2017).

The authors then define the 1947 European heatwave and identify it as the focus of their study:

This study focuses on the anomalously hot summer of 1947 over Central Europe as a case study to examine the time-evolution of attribution statements, as well as the efficacy of circulation analogues as a tool for probabilistic event attribution. As discussed extensively in Grütter et al. (2013, hereafter G13), the summer of 1947 was a period of pronounced heat over large regions of Central Europe, and occurred during the middle of a five-year period of drought which affected the region between 1945 and 1949 (Hirschi et al. 2013).

The period of April-September 1947 witnessed record-breaking rainfall deficits over Switzerland, which by some estimates were up to twice as severe as for the summer of 2003 (Calanca 2007). This widespread dryness helped to exacerbate the favourable meteorological conditions for extreme heat in Central Europe: in this case, such conditions were characterised by a persistent high-pressure system over Central Europe and several low pressure systems forming to the west of the British Isles contributing to significant heat advection from the south-west. The severity and length of this anomalous heat during the summer of 1947 lead to widespread forest fires in Germany, as well as a near-total loss of crops across Switzerland (Grütter et al. 2013).

The above graphic shows the absolute Jul-Aug temperature anomalies in Europe in 1947 compared to the 1901-2000 base period.

Obviously not a flash in the pan. A very significant meteorological event which, as we have already seen, is comparable to, and even more severe in retrospect than 2003. Emissions of greenhouse gases had yet to take off in 1947 and it was 11 years before direct measurements of atmospheric CO2 began at Mauna Loa. It’s quite likely that CO2 has increased by more than 100ppm since 1947 and that atmospheric concentrations of GHGs were far closer to pre-industrial concentrations when Europe experienced this very significant mid 20th century heatwave. It therefore defies reason that radiative forcing from GHGs could have played any significant role in that event.

The authors of the study were interested in the evolving probability of “witnessing circulation features similar to those which coincided with the 1947 heatwave through the twentieth century”. Here is what their analysis revealed:

Clear multidecadal variability. The authors state that “there is no clear positive trend through time in the likelihood of witnessing daily circulation patterns like those of the 12 days of the 1947 extreme heatwave” and furthermore that there are “some individual decades—like the 1940s in Fig. 4d—which can show statistically significant probabilities of witnessing 1947-like MSLP patterns”.  The authors further state:

Up until the 1940s—and to a lesser extent for those 20-year periods ending in the 1970s—the probability of witnessing 12-day MSLP sequences analogous to the 1947 heatwave event was substantially lower than average. Meanwhile, for every 20-year period since 1976–1995, there are substantive increases in the likelihood of witnessing such circulation analogues, with probability ratios reaching between three and six for in the most recent decades. While these results appear to qualitatively resemble corresponding changes in the Atlantic Meridional Oscillation over the same period (Sanderson et al. 2017), decomposing the relative effects of low-frequency modes of variability versus changes to European aerosol or greenhouse gas emissions (King et al. 2016; Undorf et al. 2018) is beyond the scope of this analysis.

So what we have here is the high likelihood that multidecadal variability is dictating the probability of circulation patterns occurring which would result in extreme heatwaves in Europe like 1947, 2003, and 2018. But dynamics are only one side of the equation. What about absolute temperatures?

For the case of general summertime temperatures, a clear warming signal is found through the twentieth century, with increases of more than 2 °C for the twenty-year period ending in 2014 relative to the start of the 1900s. We also find for any given time period, the average of the analogue temperatures to be approximately 2 °C warmer than the corresponding mean of all daily temperatures (black line in Fig. 5a–c), an inflation consistent with previous studies (Jézéquel et al. 2018b). This is clear evidence to support the notion that extreme summertime temperatures in 1947 were more likely to occur in the presence of the corresponding MSLP patterns which were also present.

The conclusion is plain: summers in Europe have got warmer due to the secular trend in warming experienced by most of the globe, but the probability of extreme summer heatwaves occurring due to particular circulation patterns shows no overall trend in the 20th century but is most likely controlled by multidecadal variability (the AMO). The authors clearly state that “no added increase in temperature anomalies is found associated when constraining on the circulation features of the 1947 heatwave, beyond the warming trends which are apparent for all summertime temperatures over the twentieth century.” Thus, Stott’s assertion that the probability of summers like 2003 and 2018 occurring has dramatically increased and will continue to do so, because of anthropogenic global warming, such that they become ‘the norm’ at the end of the 21st century is highly suspect and probably simply WRONG. If generalised warming continues, summer heatwaves will probably continue to set records but there is little evidence to suggest that they will become more frequent.

The authors do at least consider the possibility that thermodynamics have played a part in the late 20th/early 21st century increased probability of European heatwaves, but then say that dynamics could equally have been responsible:

A further consideration is whether or not warming-driven changes to background circulation patterns should be considered as part of the analogue analysis a priori. Jézéquel and colleagues (2018b) argue that mean changes to both Z500 and MSLP fields generally constitute a thermodynamic signal, and thus any overall trend in Z500 or MSLP through time should be removed before an analogue analysis to infer dynamical changes to the likelihood of extreme heatwaves is performed. While such an approach would be reasonable to account for the overall thermodynamic increase in tropospheric depth when considering Z500 trends, mean changes to MSLP could equally reflect dynamically driven changes in the prevalence of blocking high pressure systems in general, and thus could be argued as a dynamical signal (Smoliak et al. 2015; Parsons et al. 2016; Harrington et al. 2016; Lehner et al. 2017; Gibson et al. 2017; Woollings et al. 2018).

They leave open at least the possibility that anthropogenic influence may play a role in the evolution of the dynamical patterns conducive to extreme heatwaves – but don’t sound too hopeful:

In reality, no metric will serve as a perfect proxy for the weather systems conducive to an extreme heatwave event. Therefore, any attempt to look at changes in the frequency of witnessing such weather regimes—which one might consider to reflect the ‘dynamical’ component of a probability ratio—will in fact just be a partial representation of the ‘true’ role of human influence on circulation changes conducive to heatwave occurrence, with the remainder instead being (perhaps mistakenly) ascribed as a thermodynamic component of the probability ratio.

Then there’s land use changes, which have nothing to do with radiative GHG forcing of climate:

There are also further complicating aspects to the binary narrative of either thermodynamic or dynamic changes to the atmosphere combining to influence the likelihood of an extreme heatwave occurring. One example is the role of land-use changes and land–atmosphere feedbacks. Antecedent soil moisture anomalies can modulate the potential severity of a heatwave (Seneviratne et al. 2010), and these processes can be further influenced by anthropogenic changes to land use over the twentieth century unrelated to climate (Cook et al. 2009; Lejeune et al. 2018). Such issues have not been addressed in this analysis, and warrant further consideration.

In conclusion:

A warming world might influence how often weather patterns conducive to exceptionally hot weather will occur over Central Europe (Jézéquel et al. 2018a; Woollings et al. 2018), as well as how warm summertime temperature maxima will reach. However, our results show further work is needed to properly quantify the uncertainty of these changes, both to understand the evolution of changes in the past and as warming continues into the future.

Do you think there is any ch

2003. 2018 and now 2019: very hot (record-breakingly hot) conditions affect parts of central and northern Europe, with 2003 being by far the most significant and prolonged event. Cue, climate change hysteria from the warmist media, whacko climate crisis obsessed eco-loonies and AGW-biased scientists in search of research grants, prestige and a ‘noble cause’ for which to promote urgent action. As usual though, history often tells a less sensational tale, providing perspective on the current ‘end of the world’ narrative being perpetuated by the MSM and by emotionally and psychologically damaged members of the climate change end times Twitterati. You think I’m exaggerating? I’m not.

Screenshot_2019-07-28 James Murray on Twitter

As it happened, 25th July 2019 wasn’t the day Britain transitioned to a ‘new climate’, because the temperature record of 38.5C set in the ‘old climate’ back in 2003 was not broken (except by iffy thermometers in Cambridge Uni’s Botanical gardens, that is). But you know how it is, Little England, being the backward, rain-soaked, cake-filled, cloud-bolted little island of grey skies, xenophobes and racists that it is, can’t be expected to immediately join continental Europe in heralding the terrifying arrival of the ‘new normal’. Germany, Belgium, Netherlands and Paris all transitioned on July 25th. Boris might make matters even worse on Halloween if he takes us ‘out of Europe’ without a deal, then God only knows how long it will be before climate alarmists can say that Britain is definitely CCBAR (climate changed beyond all recognition).

July 25th, though it didn’t see the UK transition from a benign climate to something much, much more horrible, did witness a significant rift open up between different factions of the Green blob: i.e. the opportunist BBC – who’ve bought in to the climate crisis purely for ideological reasons, and because they’re rabid, globalist lefties anyway – and those nutters who genuinely believe that we are all going to die in a few years time. The latter got quite upset at those caught ‘celebrating’ the imminent ‘hottest day evah’ in Britain. They were celebrating for the simple reason that it reinforced their catastrophe narrative. The ‘serious’ fanatics really do believe that a few very hot days are a prelude to the end of the world and they really do believe that the Beeb was being outrageously flippant. It’s quite comical.

Environmentalists who criticised the BBC for tweeting enthusiastically about the ongoing heatwave have been mocked online for their hysterical reaction. 

Campaigners including the Green Party and charity WWF heaped scorn upon the Corporation for the lighthearted tone it used when reporting the heatwave on social media.

As it happens, both factions were to be bitterly disappointed. The Met Office and the BBC didn’t get to crack open the chilled Champers and the eco-loons at GreenPiss, the Green Party, XR and WWF – plus the rest of the doom-filled Thermageddon-fixated adorers of Saint Greta – didn’t get to be really, really miserable. Shame. Never mind.

But anyway, enough of the entertainment; let’s get to the boring, ‘sciency’, fact-orientated bit. Why isn’t a few extremely hot days in Europe this year proof of a climate crisis?

The 1947 heatwave was more severe in Central Europe than 2003

In 2013, scientists from the Oeschger Centre for Climate Change Research and Institute of Geography, University of Bern, Switzerland analysed the heatwaves in Switzerland during 1947 using Meteo-Swiss weather records and the 20th Century Reanalysis (20CR) dataset based on NCEP. Here is what they found:

The heatwaves of 1947 can be compared with the events of 2003 in terms of intensity and duration.

The meteorological situation was characterized by a high-pressure bridge over Central Europe.

This report focuses on the heat period of 1947 in Switzerland. The summer of 1947 marked the culmination of a prolonged drought period that affected central Europe from around 1945 to the early 1950s.

The authors make it clear that it was atmospheric dynamics (circulation patterns/blocking high) which primarily caused the heatwave – just like in 2003, 2018 and now 2019.

The variability of air temperature in general and of extreme temperature events in particular is governed by atmospheric circulation. In particular, persistent high-pressure systems and associated circulation patterns may lead to positive anomalies of surface air temperature affecting a large area over prolonged time periods (Kysely and Huth, 2008). Heatwaves are often caused by quasi-stationary anticyclonic circulation anomalies or atmospheric blocking, which may be sustained or amplified by land-atmosphere feedbacks (IPCC, 2012). This is also the case for the region under study (Rüttimann et al., 2009).

Here are the anomalies over Europe in 1947 for Apr-Jun (left) and Jul-Sep (right) (Hadcrut 3) with respect to 1981-2010. You can see the heatwave was firmly centred over Central Western Europe and covered a huge area way beyond Switzerland, which country was not even at the epicentre.

Screenshot_2019-07-28 Microsoft Word - Paper08_Heatweave_12dec2013_korrigiert doc - GB2013_G89_08 pdf

In the analysis of the maximum temperature from the 14 meteorological stations, 29 July was the hottest day during summer 1947. The mean maximum temperature from all lowland (<560 m a.s.l.) stations on this date was 36.1 °C; 26.4 °C were reached at 2502 m a.s.l. In Basel 38.7 °C were measured – the highest recorded temperature during the heat period of 1947 and the highest temperature ever observed in Switzerland until 2003 (note, however, that the Wild screen used at that time in Basel was sensitive to radiation errors, see Auchmann and Brönnimann, 2012).

The heat period of 1947 can be compared with the year 2003 in terms of maximum temperatures and duration of the heatwaves. For instance, the maximum temperature anomaly, computed as departures from the 1961-1990 average, of the year 1947 amounted to 5 °C. This is only 1 °C less than for the year 2003. Another aspect is that in Basel, the threshold of 30 °C was exceeded 49 times in 1947, more often than in 2003 (41 times). 

The period of consecutive days during which the maximum temperature exceeded the 90% quantile of the summer temperature was also longer in 1947 than in 2003. During the year 1947 the longest heatwave lasted 14 days from 22 July to 4 August, whereas in 2003 only twelve consecutive heat days were recorded at the beginning of August (Z’Graggen, 2006; Beniston, 2004).

The meteorological situation during the heatwave event in 1947 analysed with the 20CR dataset shows typical features of a heatwave. The stationary high pressure system over the study region – the Central-European High – during the episode from the 22 July to 4 August 1947 is conductive for a heatwave according to Kysely and Huth (2008).

The analysis of the heatwaves in 1947 indicates that the event is comparable to 21stcentury heat periods such as the summer 2003 and that 1947 was extraordinary.

Even if the heatwave 2003 exceeded the maximum temperatures measured in 1947, in terms of the length of a heatwave and the exceedance of the 30 °C temperature threshold, the heat period 1947 was more intense.

So it’s fairly clear that:

  • 1947 was comparable to 2003 and both heatwaves were caused by very similar meteorological patterns.
  • 1947 maximum average temperatures were just 1C less than 2003
  • In terms of duration and number of days above 30C, 1947 was more intense

Given that summers in Europe have warmed significantly since 1950, it is perhaps not surprising that the daily average maximum temperature in 2003 exceeded that in 1947, but that’s the only real difference and by all other metrics, 1947 was more intense. Not forgetting also that urbanisation has increased since 1947 and land use has changed considerably, either of which may have contributed to generally higher temperatures. So, if you’re looking for the climate change signal in the heatwave of 2003, the increase in mean maximum temperature anomaly of 1C is it. Scary (not). Climate crisis (not). But Peter Stott et al say different:

Dramatically increasing chance of extremely hot summers since the 2003 European heatwave

A study by Christidis, Jones and Stott published Dec 2014 claims:

The vulnerability of European citizens was made evident during the summer heatwave of 2003 (refs 34) when the heat-related death toll ran into tens of thousands5Human influence at least doubled the chances of the event according to the first formal event attribution study6, which also made the ominous forecast that severe heatwaves could become commonplace by the 2040s. Here we investigate how the likelihood of having another extremely hot summer in one of the worst affected parts of Europe has changed ten years after the original study was published, given an observed summer temperature increase of 0.81 K since then.

Using a previously employed temperature threshold to define extremely hot summers, we find that events that would occur twice a century in the early 2000s are now expected to occur twice a decade. For the more extreme threshold observed in 2003, the return time reduces from thousands of years in the late twentieth century to about a hundred years in little over a decade.

Note the emphasis is on frequency of recurrence. Stott’s original attribution study of the 2003 heatwave categorised the event as:

 . . . . . probably the hottest in Europe since at latest ad 1500

Thereby classing it as a millennial scale event. However, we’ve just seen that 1947 was comparable to 2003 and only 1C cooler in terms of mean absolute maximum temperature. Also, the summer of 1541 was likely hotter, drier and far more intense than even 1947 or 2003. Stott paints the 2003 heatwave as some momentous event in the history of European weather and claims that, because of man-made climate change, such events are going to be ‘the new normal’ by the end of the 21st century. Stott is wrong about the uniqueness of 2003 in modern European meteorological history. 1947 was worse. 1976 was definitely worse – in the UK at least.

We’ve seen two heatwaves in Europe in 2018 and 2019, of similar intensity to 2003, but of shorter duration and impact (especially so far in 2019), with the 2018 heatwave being centred more over Scandinavia, the UK and Ireland – similar to 1976. Also, very inconveniently, many areas of Europe and Russia have experienced record summer minimum temperatures in 2019, whilst other parts were baking, but you didn’t hear about that in the media. But even so, perhaps Stotty is right about the increased probability of European heatwaves? Maybe they are becoming hotter and a lot more frequent due to man-made climate change? The climate fanatics certainly think so. To investigate this possibility though, we have to look at atmospheric dynamics, not just simple thermodynamics and, as it turns out, the answer is not that simple. Science and observations get in the way of warmist hyperbole. Bummer.

Observed 21st Century Increase of Jet Stream Blocking Events

study published in April this year states:

The summer of 2018 witnessed a number of extreme weather events such as heatwaves in North America, Western Europe and the Caspian Sea region, and rainfall extremes in South-East Europe and Japan that occurred near-simultaneously. Here we show that some of these extremes were connected by an amplified hemisphere-wide wavenumber 7 circulation pattern. We show that this pattern constitutes an important teleconnection in Northern Hemisphere summer associated with prolonged and above-normal temperatures in North America, Western Europe and the Caspian Sea region. This pattern was also observed during the European heatwaves of 2003, 2006 and 2015 among others. We show that the occurrence of this wave 7 pattern has increased over recent decades.

So what exactly has happened and can what has happened be attributed to anthropogenic influence?

Over recent decades the number of phase-locked wave-7 events (here defined as weeks with above average wave-7 amplitude within its preferred position, see figure S4) have increased significantly (95% confidence interval, figure 4(b)). Prior to 1999 there were no summers with two or more consecutive weeks of a wave 7 phase-locked circulation, but since then these have occurred (table S2). Thus, the persistence of such situations appears to have increased. In fact, the average duration has doubled from about one to two weeks per year, while the number of years with more than two events per summer shows an almost eight-fold increase (figure S7). Although the trends are always upward, i.e. independent of the amplitude threshold used, their significance is sensitive to the amplitude threshold due to the reduction in ensemble size for high amplitudes (figure 4(b)). The number of wave-7 events (i.e. weeks with a high-amplitude wave-7 irrespective of its phase position) do not show statistically significant upward trends for different thresholds used (figure 4(a)). A statistically significant upward trend in the observed amplitude of summertime wave-7 is only detected when data from the pre-satellite period is included (figure S8). The more pronounced trends in phase-locked events (figure 4(b)), compared to high-amplitude events (figure 4(a)) suggests that it is the phase-locking itself that has increasedIn general, these trends can simply reflect multi-decadal variability in the Earth system given that the satellite record is relatively shortNevertheless, an enhanced land-ocean temperature contrast as a consequence of amplified land warming provides a physical mechanism for such waves to become preferentially phase-locked. Such temperature contrast creates an increased zonal temperature gradient at the coastlines and provide a stationary vorticity source that triggers and maintains atmospheric waves [3031]. It is therefore possible that the relative position of land and ocean areas in the mid-latitudes with high values of dT/dx over the continental West-coasts could favor a hemispheric wave 7 pattern [32]. Such contrast would further be enhanced by the cooling trend of northern Atlantic sea surface temperatures linked to a slowdown of the Atlantic Meridional Overturning Circulation [33] and implicated in past European heat extremes [23] but this needs further investigation.

So, what the authors are saying here is that there is no trend in wave 7 phase locking events which would give rise to particularly hot summers in western Europe over the period of satellite observation, but that there is a very significant increase in phase locking events after 1999, which has resulted in a number of hot summers in Europe, including the very hot summer of 2003 and the memorable hot dry early summer of 2018 in north western Europe. What they say is that natural multidecadal variability may be the cause behind this change but that it’s plausible it may be due to Arctic warming, which implies anthropogenic causes (though note that this is only the case if such warming is attributable largely to anthropogenic causes).

Take home message: no increase in blocking over the period of satellite observations, only a 21st century increase which may be due to natural causes or possibly anthropogenic influence. More research needed.

1947 was a circulation-induced heatwave analogous to modern heatwaves

An interesting new study looking at 1947 as an analogue of more recent European heatwaves was published in May this year and Friederike Otto is among the authors. It’s rather better science, I must say, than the shockingly poor event attribution which was plugged by the media as ‘proof’ that the recent record breaking heatwave in France was man-made, which she also co-authored. The abstract says:

The science of extreme event attribution has rapidly expanded in recent years, with numerous studies dedicated to determining whether and to what extent anthropogenic climate change has increased the likelihood of specific extreme weather events occurring. However, the majority of such studies have focussed on extreme events which have occurred in the recent past (usually within the past 10 years) while minimal research efforts have considered the multitude of high-impact extreme climatic events which occurred throughout the instrumental record.

Using a reanalysis-based dataset, our results show changes in the frequency of 1947-like extreme heat throughout the twentieth century to be highly sensitive to methodological choices, particularly in the context of disaggregating dynamic and thermodynamic changes in the risk of extreme heat. Evidence also suggests clear decadal variability in the occurrence of circulation patterns conducive to the 1947 heatwaves.

The authors make the clear distinction between dynamic and thermodynamic influences when considering attribution of extreme events like European heatwaves:

Since European heatwaves are known to preferentially occur in the presence of specific summertime atmospheric circulation states (Cassou et al. 2005; Pfahl and Wernli 2012; Sousa et al. 2018; Jézéquel et al. 2018b), it is important to understand how dynamic and non-dynamic processes leading to heatwaves are each affected by anthropogenic climate change. Consequently, a second topic of recent research for the attribution community has concerned the extent to which changes in the likelihood of a particular extreme event occurring can be further separated into dynamic and thermodynamic contributions (Trenberth et al. 2015; Shepherd 2016; Otto et al. 2016; Harrington 2017).

The authors then define the 1947 European heatwave and identify it as the focus of their study:

This study focuses on the anomalously hot summer of 1947 over Central Europe as a case study to examine the time-evolution of attribution statements, as well as the efficacy of circulation analogues as a tool for probabilistic event attribution. As discussed extensively in Grütter et al. (2013, hereafter G13), the summer of 1947 was a period of pronounced heat over large regions of Central Europe, and occurred during the middle of a five-year period of drought which affected the region between 1945 and 1949 (Hirschi et al. 2013).

The period of April-September 1947 witnessed record-breaking rainfall deficits over Switzerland, which by some estimates were up to twice as severe as for the summer of 2003 (Calanca 2007). This widespread dryness helped to exacerbate the favourable meteorological conditions for extreme heat in Central Europe: in this case, such conditions were characterised by a persistent high-pressure system over Central Europe and several low pressure systems forming to the west of the British Isles contributing to significant heat advection from the south-west. The severity and length of this anomalous heat during the summer of 1947 lead to widespread forest fires in Germany, as well as a near-total loss of crops across Switzerland (Grütter et al. 2013).

Screenshot_2019-07-29 Circulation analogues and uncertainty in the time-evolution of extreme event probabilities evidence f[...]

The above graphic shows the absolute Jul-Aug temperature anomalies in Europe in 1947 compared to the 1901-2000 base period.

Obviously not a flash in the pan. A very significant meteorological event which, as we have already seen, is comparable to, and even more severe in retrospect than 2003. Emissions of greenhouse gases had yet to take off in 1947 and it was 11 years before direct measurements of atmospheric CO2 began at Mauna Loa. It’s quite likely that CO2 has increased by more than 100ppm since 1947 and that atmospheric concentrations of GHGs were far closer to pre-industrial concentrations when Europe experienced this very significant mid 20th century heatwave. It therefore defies reason that radiative forcing from GHGs could have played any significant role in that event.

The authors of the study were interested in the evolving probability of “witnessing circulation features similar to those which coincided with the 1947 heatwave through the twentieth century”. Here is what their analysis revealed:

Screenshot_2019-07-29 Circulation analogues and uncertainty in the time-evolution of extreme event probabilities evidence f[...] (2).png

Clear multidecadal variability. The authors state that “there is no clear positive trend through time in the likelihood of witnessing daily circulation patterns like those of the 12 days of the 1947 extreme heatwave” and furthermore that there are “some individual decades—like the 1940s in Fig. 4d—which can show statistically significant probabilities of witnessing 1947-like MSLP patterns”.  The authors further state:

Up until the 1940s—and to a lesser extent for those 20-year periods ending in the 1970s—the probability of witnessing 12-day MSLP sequences analogous to the 1947 heatwave event was substantially lower than average. Meanwhile, for every 20-year period since 1976–1995, there are substantive increases in the likelihood of witnessing such circulation analogues, with probability ratios reaching between three and six for in the most recent decades. While these results appear to qualitatively resemble corresponding changes in the Atlantic Meridional Oscillation over the same period (Sanderson et al. 2017), decomposing the relative effects of low-frequency modes of variability versus changes to European aerosol or greenhouse gas emissions (King et al. 2016; Undorf et al. 2018) is beyond the scope of this analysis.

So what we have here is the high likelihood that multidecadal variability is dictating the probability of circulation patterns occurring which would result in extreme heatwaves in Europe like 1947, 2003, and 2018. But dynamics are only one side of the equation. What about absolute temperatures?

For the case of general summertime temperatures, a clear warming signal is found through the twentieth century, with increases of more than 2 °C for the twenty-year period ending in 2014 relative to the start of the 1900s. We also find for any given time period, the average of the analogue temperatures to be approximately 2 °C warmer than the corresponding mean of all daily temperatures (black line in Fig. 5a–c), an inflation consistent with previous studies (Jézéquel et al. 2018b). This is clear evidence to support the notion that extreme summertime temperatures in 1947 were more likely to occur in the presence of the corresponding MSLP patterns which were also present.

The conclusion is plain: summers in Europe have got warmer due to the secular trend in warming experienced by most of the globe, but the probability of extreme summer heatwaves occurring due to particular circulation patterns shows no overall trend in the 20th century but is most likely controlled by multidecadal variability (the AMO). The authors clearly state that “no added increase in temperature anomalies is found associated when constraining on the circulation features of the 1947 heatwave, beyond the warming trends which are apparent for all summertime temperatures over the twentieth century.” Thus, Stott’s assertion that the probability of summers like 2003 and 2018 occurring has dramatically increased and will continue to do so, because of anthropogenic global warming, such that they become ‘the norm’ at the end of the 21st century is highly suspect and probably simply WRONG. If generalised warming continues, summer heatwaves will probably continue to set records but there is little evidence to suggest that they will become more frequent.

The authors do at least consider the possibility that thermodynamics have played a part in the late 20th/early 21st century increased probability of European heatwaves, but then say that dynamics could equally have been responsible:

A further consideration is whether or not warming-driven changes to background circulation patterns should be considered as part of the analogue analysis a priori. Jézéquel and colleagues (2018b) argue that mean changes to both Z500 and MSLP fields generally constitute a thermodynamic signal, and thus any overall trend in Z500 or MSLP through time should be removed before an analogue analysis to infer dynamical changes to the likelihood of extreme heatwaves is performed. While such an approach would be reasonable to account for the overall thermodynamic increase in tropospheric depth when considering Z500 trends, mean changes to MSLP could equally reflect dynamically driven changes in the prevalence of blocking high pressure systems in general, and thus could be argued as a dynamical signal (Smoliak et al. 2015; Parsons et al. 2016; Harrington et al. 2016; Lehner et al. 2017; Gibson et al. 2017; Woollings et al. 2018).

They leave open at least the possibility that anthropogenic influence may play a role in the evolution of the dynamical patterns conducive to extreme heatwaves – but don’t sound too hopeful:

In reality, no metric will serve as a perfect proxy for the weather systems conducive to an extreme heatwave event. Therefore, any attempt to look at changes in the frequency of witnessing such weather regimes—which one might consider to reflect the ‘dynamical’ component of a probability ratio—will in fact just be a partial representation of the ‘true’ role of human influence on circulation changes conducive to heatwave occurrence, with the remainder instead being (perhaps mistakenly) ascribed as a thermodynamic component of the probability ratio.

Then there’s land use changes, which have nothing to do with radiative GHG forcing of climate:

There are also further complicating aspects to the binary narrative of either thermodynamic or dynamic changes to the atmosphere combining to influence the likelihood of an extreme heatwave occurring. One example is the role of land-use changes and land–atmosphere feedbacks. Antecedent soil moisture anomalies can modulate the potential severity of a heatwave (Seneviratne et al. 2010), and these processes can be further influenced by anthropogenic changes to land use over the twentieth century unrelated to climate (Cook et al. 2009; Lejeune et al. 2018). Such issues have not been addressed in this analysis, and warrant further consideration.

In conclusion:

A warming world might influence how often weather patterns conducive to exceptionally hot weather will occur over Central Europe (Jézéquel et al. 2018a; Woollings et al. 2018), as well as how warm summertime temperature maxima will reach. However, our results show further work is needed to properly quantify the uncertainty of these changes, both to understand the evolution of changes in the past and as warming continues into the future.

Do you think there is any chance at all that the world’s media will convey this non-alarmist message to the public and do you think little Greta, who knows all about the ‘science’ of the ‘climate crisis’, will tweet the good news to her thousands of followers on Twitter? Any chance that Rupert Read of XR will go on telly and announce “OK, maybe we do have a bit more than 18 months to save the planet”? Any chance at all that the scientists involved in these studies will go public and explain that extreme heatwaves in Europe and beyond are not necessarily due to fossil fuel burning, in fact rather more likely due to natural variability? Not bloody likely!

ance at all that the world’s media will convey this non-alarmist message to the public and do you think little Greta, who knows all about the ‘science’ of the ‘climate crisis’, will tweet the good news to her thousands of followers on Twitter? Any chance that Rupert Read of XR will go on telly and announce “OK, maybe we do have a bit more than 18 months to save the planet”? Any chance at all that the scientists involved in these studies will go public and explain that extreme heatwaves in Europe and beyond are not necessarily due to fossil fuel burning, in fact rather more likely due to natural variability? Not bloody likely!

#Rep 2 – What The Media Didn’t Tell You About The ‘Man-Made’ June 2019 European Mini Heatwave – Climate Models FAILED To Make The Link

Posted on  by Jaime JessopIn Uncategorized13 Minutes Read

The guys and gals at World Weather Attribution have pulled a white rabbit out of the hat yet again to confirm to a breathlessly waiting queue of climate activists, alarmists and media hacks their worst suspicions – yes, humans did indeed make the recent June heatwave in France much more likely and more intense. Peter Stott is one of the authors of the retrospective rapid extreme weather attribution study. Quite why, I’m not sure because he already knew that it was climate change wot dunnit before the heatwave actually happened! Was it tea leaves, Tardis or entrails I wonder which bestowed this remarkable foresight upon Peter? Actually, Peter would make quite a good Doctor, don’t you think? Perhaps he should think about auditioning for the BBC.

Joking aside, let’s get to the serious stuff. Let’s actually examine the study which headlines across the world declared was proof positive that the European heatwave was man-made. Did the writers of those headlines actually read the study? I doubt it somehow. Most of them were probably just briefed by the scientists involved or they got their info second hand from other media sources.

What the papers say

So before getting into the nitty gritty, let’s look at a few of those official tweets, headlines and media stories which have promoted the idea that your SUV, washing machine and toaster were responsible for France baking in extreme high temperatures for three days from June 26-28.

CNN headline says:

Climate crisis made European heat wave ‘at least’ five times more likely

In the text, Friederike Otto, another of the above study’s authors, is quoted as saying:Acting Director of the Environmental Change Institute at Oxford University Friederike Otto, who contributed to the research, told CNN that the findings give the most conservative assessment of the impact of human activity on the heatwave.“It’s important to stress the ‘at least’. It’s likely to be much higher but this is hard to quantify. Our best estimate is that it’s 100 times more. We give the most conservative estimate,” Otto said.

Scam (Scientific American) reports:

For one group of climate scientists, the event presented a rare opportunity: to rapidly analyse whether the cause of the heatwave — which made headlines around the world — could be attributed to global warming. After a seven-day analysis, their results are in: climate change made the temperatures reached in France last week at least five times more likely to occur than in a world without global warming.

The scientists with the World Weather Attribution Project decided to take action when they saw the heatwave coming and ended up performing a real-time analysis while at a climate conference in Toulouse, France.

“Some say the uncertainties are too big,” says Otto. “There are indeed caveats, mostly to do with imperfect climate models. But even with large uncertainty bars we think it is useful to provide quantitative evidence for how climate change is affecting extreme weather,” she says.

Using their models, the researchers calculated that the average temperatures reached over the three hottest days in France — around 28°C — were at least five times more likely to happen because of climate change.

But in a second analysis that looked at historical temperature records over the past century rather than models, the team calculated that the likelihood of such a heatwave in June has in fact increased 100 times since around 1900, owing to the combined influence of climate change and other factors such as air pollution.

Here’s what the British version of Scam, New Scientist, tweeted:

The Graun’s headline and sub-heading says:

Climate change made European heatwave at least five times likelier

Searing heat shows crisis is ‘here and now’, say scientists, and worse than predicted

Underneath, we read:

The record-breaking heatwave that struck France and other European nations in June was made at least five – and possibly 100 – times more likely by climate change, scientists have calculated.

Such heatwaves are also about 4C hotter than a century ago, the researchers say. Furthermore, the heatwaves hitting Europe are more frequent and more severe than climate models have predicted.

Dr Friederike Otto, of the University of Oxford, one of the scientists behind the new analysis, said: “This is a strong reminder again that climate change is happening here and now. It is not a problem for our kids only.”

The researchers, many of whom happened to be at a conference on extreme events and climate change in Toulouse, then used temperature records stretching back to 1901 to assess the probability of a heatwave last month and in the past. They also examined climate change models to assess the impact of global heating.

Global heating caused by human activities made the French heatwave at least five times more likely, said Otto, based on combining the observations and climate models. Analysis of the observations alone indicated the heatwave was at least 10 times more likely than a century ago, and potentially 100 times.

However, these bigger increases in probability may result in part from changes in land use, soil moisture and irrigation, the growth of towns and cities, and air pollution, all of which can affect temperature.

You get the idea. We’re all going to fry, not boil slowly, like frogs in a gently heated saucepan, but like prawns, flash-fried in a wok, via heatwaves so intense that not even the climate models predicted just how intense they would be. The climate crisis is happening here and now.

The World Weather Attribution rapid attribution study

So what does the attribution study actually say? Well, in summary, at the beginning, it states:

The observations show a very large increase in the temperature of these heat waves. Currently such an event is estimated to occur with a return period of 30 years, but similarly frequent heat waves would have likely been about 4ºC cooler a century ago. Climate models have systematic biases in representing heat waves at these scales and show smaller trends, more year-on-year variation and fewer really severe heat waves than the observations. Combining models and observations we conclude that the heat wave was made at least 5 times more likely.

Why did the heatwave occur?

The authors tell us:

The heat wave occurred rapidly after a rather cool period in the early phase of June. This sudden change was mostly due to the specific dynamical conditions that were present, with a mid-tropospheric “cut-off low” system that formed off the coast of the Iberian peninsula (see the 500 hPa map on 27/6/2019 in Figure 2a). This system created a transport of heat from low-level Saharan air, and induced extreme temperatures at 850 hPa (Figure 2c) and in mountainous areas, such as 29°C at 1600-1800m in the Alps. These dynamical conditions, transporting hot Saharan air or air arising from the Iberian Peninsula are unusual (see analysis below). In particular the fact that the resulting transport of air masses remained at a very low level across the Mediterranean sea over five days was very unusual.

So it’s clear. The reason the heatwave occurred was because of a rare meteorological set of events, precipitated as we have already noted by what is known as a phase-locked wave 7 pattern of the northern hemisphere jet stream which is currently in an exaggerated wavy (meridional) configuration.

Event definition

We defined the event as the highest 3-day averaged daily mean temperature in June (TG3x). The daily temperature is taken as the average over France and at the city of Toulouse in southern France.

As the intense heatwave only really lasted three days, this would seem to be an obvious choice, though it doesn’t qualify as a heatwave according to the WMO’s definition:

The World Meteorological Organization defines it [a heatwave] as five or more consecutive days during which the daily maximum temperature surpasses the average maximum temperature by 5 °C (9 °F) or more.

The short duration reflects the fact that there were apparently no deaths reported attributable directly to heat exhaustion or hyperthermia. For comparison, 15,000 people died during the prolonged heatwave of 2003.

What observational temperature dataset was used?

For the average over France we use the official Météo France definition, which is the average over 30 long-term homogenised stations. Unfortunately, this series is not public but the area average of the E-OBS daily mean temperature over metropolitan France gives virtually identical results. This time series shows previous hot events around 1950, one in 1976, and further ones in 2005 and 2017, in addition to the present event, which set a record for June of 27.5 °C (the 2003 heat wave was more intense but occurred in August, not June). The 10-yr running mean (green line) shows a combination of the increasing trend due to greenhouse gases and a cooling phase around 1980 mainly due to air pollution (aerosols).

The dataset which can’t be examined because it is not public goes back only as far as 1947 and is virtually identical to another set of observations which cover metropolitan France. Hmm. UHI bias anyone? Here is the graph of the time series which the authors used:

Note how the authors attribute the ‘warming trend’ to anthropogenic GHGs and explain away the mid 20th century cooling to anthropogenic aerosols. By doing so, they have virtually done the attribution study for observations there and then – it’s all anthropogenic according to them. No confirmation bias there then! Rational people with a fair knowledge of climate change and its causes would look at that graph and note that it could actually be the truncated part of a cycle – a natural cycle – with mid 20th century cooling, pre 1950 warming and post mid 70s rapid warming at least partly explained by natural internal variability. rational people would also note that there’s not much of a warming trend across the entire (somewhat short) series and that it is only June 2019 which stands out. Similar heat events occurred at the beginning of the series and indeed the June 1976 heat spike occurred right at the end of the mid 20th century cooling, when the authors contend that aerosols were masking the GHG warming. So according to their analysis, 1976 3 day June temperature would have been even hotter still, maybe hotter than 2019, when atmospheric CO2 concentration was around 330ppm vs. 410ppm in 2019!

Note also that the hottest 3 day max June temperature was about 25.5C in 1947 and showed no increase before 2017, which year it edged up to about 26.3C, then leapt to 27.5C this year apparently. This, we’re told, is climate change in action. But where did the 4C figure come from?

How the attribution study estimated 4C anthropogenic warming of 3 day June heatwaves

Simple really. They used the 3-day max series from 1947-2018 and plotted it against the Hadcrut 4.6 anomaly for western Europe during June July August and then drew a linear trend line through the highly variable data. Then they extrapolated the linear trend back to 1900 when anthropogenic warming was thought to be negligible. Hence they ended up with 4C of 3-day heatwave warming (since 1900) which they attributed in its entirety to GHGs released since 1900!

We fit a Generalised Extreme Value distribution (GEV) to the French series (figure 5). The trend is included by allowing for a shift in proportion to the European summer temperature. This gives a good description of 3-day heat in France. We extrapolated the linear relationship found to 1900 to obtain an estimate of the total warming since a time when anthropogenic influences were small

The mean observed summer land temperature warming in western Europe according to Hadcrut 4.6 is about 2C apparently, so how to explain the 4C 3 day heatwave warming? The authors write:

This implies a much higher warming trend in France in June compared to that of the average European land summer temperature, which has warmed by about two degrees. More research is needed to understand this feature, but a major factor in the difference is likely the amplification that soil moisture drying contributes to temperature means and extremes in regions with transitional climate between dry and wet conditions. This effect is known to be strong in southern France and other regions with Mediterranean climate and is getting stronger in mid-latitude regions with global warming (because of decreased evaporative cooling if soil moisture levels become limiting for plants’ transpiration; e.g. Seneviratne et al, (2010), Mueller and Seneviratne (2012). Nonetheless, the derived value is particularly high compared to the warming in the European land and could also be affected by additional contributing factors or reflect some shortcomings of the analysis. For instance, the fit was derived from 60 years of data (Figure 5, left) and it is possible that there could be non-linearities in the relationship, e.g., because of a threshold behaviour which could imply a different relationship to European temperatures earlier in the century compared to the derived relationship. In addition, the role of soil moisture feedbacks could be different for means vs extremes, both in France as well as for the European temperatures (since it may also play an amplifying role during extreme conditions in more northern regions). It should be noted that the strength of the feedback may also depend on the month considered (e.g. likely stronger drying at the end of the summer season). Other processes that could also contribute are landscape changes or specific dynamical conditions occurring during hottest extremes in France, which could include hot advections from Spain or Sahara, making the underpinning physical processes different for mean vs extreme cases.

A lot of uncertainties and unknowns and caveats in there, very few of which found their way into the media reports and which the authors themselves – more especially Friederike Otto – appeared not to be too concerned about expressing, preferring instead to concentrate on the climate crisis narrative.

What did the study say about dynamics (i.e. meteorological effects/the jet stream)?

Basically, it concluded that the dynamical set up which is the direct cause of the heatwave cannot be attributed to climate change.

We do not identify a trend. This analysis thus does not suggest a strong role of climate change in this dynamical aspect of the extreme June heat.

They conclude that the meteorological situation was highly unusual in June 2019 but that no trend can be observed in the data going back to 1949.

What do the climate models tell us about the attribution of the European heatwave?

The fundamental basis of an extreme weather attribution study is a comparison between a world without added GHGs and just natural climate variability and a world with added GHGs as simulated by running climate models. Comparing natural to anthro model runs in the context of the observed event should enable an estimate of the influence which GHGs have played. That’s the whole point of the exercise. So what did the climate models used in this study reveal? Nothing, basically, they were useless, not fit for purpose!

Before undertaking the attribution analysis using climate models we have to evaluate whether the models readily available to us are fit for purpose and represent the statistics of the TG3x June event well. We considered the following models to investigate the changes in heat waves in France (Table 1)

Taking the two tests together we find that only one model ensemble or single model (barely) passes the test that the fit parameters of the tail of the distribution have to be compatible with the parameters describing the observations; a situation similar to the one encountered for area-averaged heat waves in the eastern Mediterranean (Kew at al, 2019). A more careful study would also investigate whether the observational analysis did not introduce biases in the fit values for the observations.

For a single station, Toulouse, we find similar results: the two models that do not have an incompatible scale parameter (Figure 11) have incompatible shape parameters (Figure 12), so here no model passes the formal tests. From the analyses for the shape parameter, we see that the CMIP5 multi-model ensemble actually has some overlap with the observations (Fig. 11), however it is outside the range of the observed scale parameters (Fig. 10). Hence, we are formally left for the present analysis with no suitable climate models or model ensembles to do the attribution (though we did not check the suitability of each single CMIP5 models and cannot exclude that some might be suitable for both parameters).

Got that? No models were found to pass the suitability tests so the attribution analysis could not be done. So what the hell did they do?

Having thus no well suited models from the analysed sample for the investigated event and locations at this stage, we decide not to give a synthesised overall result drawn from observations and models as in previous studies (refs) but still proceed with analysing all models, noting that the results are only indicative at best when drawing conclusions.

Can you believe that? Presumably so desperate to a get a non peer reviewed attribution study out in the public domain as quickly as possible they went ahead and did it anyway, using models which they knew were not suitable for the purpose! It worked though didn’t it. They got the global headlines they wanted – but the analysis is total BS, based on using models which are, by the authors own admission, not fit for purpose.

Then comes the pièce de résistance of this French heatwave study, the glacé cherry on top of the BS cake:

For the average over France we find that the probability has increased by at least a factor five (excluding the model with very strong bias in variability). However, the observations show it could be much higher still, a factor 100 or more. Similarly, the observed trend in temperature of the heat during an event with a similar frequency is around 4 ºC, whereas the climate models show a much lower trend.

Let’s deconstruct this short, innocent looking paragraph. Using models which are total crap, they find the probability of such a heatwave occurring has increased by a factor of five due to climate change. Looking at the observations (which prove nothing about attribution), they conclude that it could be as much as a factor of 100! Using the ‘observed trend’ of 4C (which is not an observed trend, it’s a linear extrapolation) the authors go public and declare that heatwaves in France are 4C hotter, implying this is due to climate change and furthermore state that an increase in probability of 5 times is a “conservative estimate” and the “best estimate” is 100 times. This “best estimate” appears to have been plucked out of the blue with no reference to the climate model runs (which cannot be relied upon anyway), simply by looking at 60 years of observations with limited amounts of data on similar heatwaves and extrapolating this back to a point 118 years ago when it is assumed that anthropogenic forcing of climate started, assuming also that anthropogenic aerosols were responsible for mid 20th century cooling.

The estimated 4C warming since 1900, which the climate models comprehensively failed to simulate, giving much lower warming generally, was used as the benchmark for the “best estimate” of the increased probability of the heatwave occurring, i.e. 100 times more likely. It’s hard to stress just how wrong this is. It’s attributing observed changes to man-made climate change using no evidence whatsoever other than the mere fact of the observations themselves. Astonishingly bad science and deliberate deception of the public in my opinion.

#Rep 1 – Attributing The 2018 Northern European Heatwave to Climate Change

Posted on  by Jaime JessopIn Uncategorized11 Minutes Read

Rapid extreme weather attribution, aka climate ambulance chasing, has come of age and the attributors are in high demand:

For Friederike Otto, a climate modeller at the University of Oxford, UK, the past week has been a frenzy, as journalists clamoured for her views on climate change’s role in the summer heat. “It’s been mad,” she says. The usual scientific response is that severe heatwaves will become more frequent because of global warming. But Otto and her colleagues wanted to answer a more particular question: how had climate change influenced this specific heatwave? After three days’ work with computer models, they announced on 27 July that their preliminary analysis for northern Europe suggests that climate change made the heatwave more than twice as likely to occur in many places.

Soon, journalists might be able to get this kind of quick-fire analysis routinely from weather agencies, rather than on an ad hoc basis from academics. With Otto’s help, Germany’s national weather agency is preparing to be the first in the world to offer rapid assessments of global warming’s connection to particular meteorological events. By 2019 or 2020, the agency hopes to post its findings on social media almost instantly, with full public reports following one or two weeks after an event. “We want to quantify the influence of climate change on any atmospheric conditions that might bring extreme weather to Germany or central Europe,” says Paul Becker, vice-president of the weather agency, which is based in Offenbach. “The science is ripe to start doing it”.

So it will be just like getting the weather report, albeit just a few days or even just hours after the event, but in this case, you’ll get to know whether storm, heatwave, drought, deluge or freezing spell is simply ‘weather’, or whether it is all the fault of those nasty anthropogenic CO2 molecules which keep popping up in our atmosphere courtesy of our exhaust pipes and modish technological lifestyles. Presumably, if found guilty, we can then all engage in a universal display of repentance, lashing ourselves with the electrical flex ripped from the back of the new dishwasher or cinematic 60 inch flat screen TV with 3D surround sound, slash the tyres on the 4×4, and say ‘it’s a fair cop’ when the insurance company rejects our claim for damage to the roof because it was ‘not a natural disaster’. Oh yes, ’twill be fun.

But before we get too carried away, and start thinking about smashing up the old C-rated washing machine in an anguished fit of remorse, let’s take a look at the supposed damning scientific evidence that we did in fact cause ourselves to cook this summer in what will probably turn out to be the hottest, longest and driest heatwave in parts of northern Europe since way back when it was last this hot and dry. Take it away World Weather Attribution:

Here we present an attribution study of the ongoing heat wave made in near real time using well assessed methodologies. It is not peer-reviewed and was written quickly. We used thoroughly tested methods to do the analysis, evaluation of models and checked the observations for errors. The return times are partly based on forecasts and therefore have additional uncertainties. However, the changes in probability are based on past observations and model results, and the authors are confident that these results are robust. We are very grateful to Peter Thorne and Peter Thejll for making the Irish (from Met Eiréann) and Danish (from DMI) temperature observations available to us.

A summary of the key findings of this quick-fire attribution:

  • The heat (based on observations and forecast) is very extreme near the Arctic circle, but less extreme further south: return periods are about 10 years in southern Scandinavia and Ireland, five years in the Netherlands
  • From past observations and models we find that the probability of such a heatwave to occur has increased everywhere in this region due to anthropogenic climate change, although in Scandinavia this increase was not visible in observations until now due to the very variable summer weather.
  • We estimate that the probability to have such a heat or higher is generally more than two times higher today than if human activities had not altered climate.
  • Due to the underlying warming trend even record breaking events can be not very extreme but have relatively low return times in the current climate.
  • With global mean temperatures continuing to increase heat waves like this will become even less exceptional

The authors then define the event thus: “To define the event, we analyse the three-day maximum temperature average (TX3x) at individual locations.” This produces the heat map below:

Anomalies are with respect to the 1981-2010 climate normal. You will notice immediately that it has not been very hot, in fact really quite cool, across most of southern Europe. Presumably this is why the authors chose a number of weather stations in Ireland, northern Europe and Scandinavia to analyse the event. The station locations are:

  • Phoenix Park (Dublin, Ireland, 53.36N, -6.32E, 49.0m),
  • De Bilt (Netherlands, 52.10N, 5.18E, 1.9m),
  • Landbohøjskolen (Copenhagen, Denmark, 55.7N; 12.5E, 9m),
  • Oslo Blindern (Norway, 59.94N, 10.72E, 94.0m),
  • Linköping (Sweden, 58.40N, 15.53E, 93.0m),
  • Sodankyla (Finland, 67.37N, 26.63E, 179.0m) and
  • Jokioinen (Finland, 60.81N, 23.50E, 104.0m).

The authors explain the rationale:

In this article we do not analyse large area averages or country averages as in previous analyses of high temperatures but focus instead on a number of individual locations in Northern Europe where long records of observed data are available.

We firstly analyze observed temperatures and estimate how rare the current heat wave is, measured as three-day maximum temperatures, and whether or not there is a trend toward increasing temperature.

So basically, the actual analysis is only applicable for these 7 station locations, though obviously, regions outside these locations were affected by the anomalous weather too, the UK in particular; hence the numerous comparisons to 1976, 1995, 2003 etc. summer heatwaves.

They analyse the observed temps to see how rare they are in the context of the existing historical records and they also compare these with models:

Secondly, to assess the role of climate change, we compare observations with results from climate models that are available and suitable for the temperatures in these locations. This answers the question whether and to what extent external drivers, in particular human-caused climate change, can explain the temperature trends in the observational data. Including models allows us to give the causation of a trend.

This makes it very clear that the attribution stems from the use of the models. Now here’s where the fun starts:

Key Assumptions About AGW And Natural Variability

For transient simulations of the changing climate, we again calculate how the probability of the event is changing over time in the model data, by fitting the temperature values to a distribution that shifts proportional to the smoothed global mean temperature. This method assumes that global warming is the main factor affecting local temperatures since about 1900, and that virtually all global warming is attributable to anthropogenic factors. In Europe, with very little decadal variability, the first condition is met. The second assumption is the conclusion of the IPCC, but disregards the uncertainty surrounding it (IPCC WG1 AR5 Chapter 10).

My bold. The authors assume that all global warming since 1900 is anthropogenic and that this is the main factor affecting temperature at the specified locations. They justify these assumptions by reference to IPCC WG1 AR5 Ch. 10. They also state, bare-faced, that northern European climate is subject to very little decadal variability . . . .

Let’s deal with the second assumption first, that most or all global warming since 1900 is anthropogenic. Let us go to AR5 WG1 Ch. 10 and see what it says about the attribution of warming post 1900. When we do, we find it has an awful lot to say about attribution post 1950, stating it is extremely likely that most or all of the warming 1951-2010 is due to GHGs. 1900 to 2010, not so much. What it does say is this:

The pattern of warming and residual differences between models and observations indicate a role for circulation changes as a contributor to early 20th cenury warming (Figure 10.2), and the contribution of internal variability to the early 20th century warming has been analysed in several publications since the AR4. Crook and Forster (2011) find that the observed 1918–1940 warming was significantly greater than that simulated by most of the CMIP3 models. A distinguishing feature of the early 20th century warming is its pattern (Brönnimann, 2009) which shows the most pronounced warming in the Arctic during the cold season, followed by North America during the warm season, the North Atlantic Ocean and the tropics.

Some studies have suggested that the warming is a response to the AMO (Schlesinger and Ramankutty, 1994; Polyakov et al., 2005; Knight et al., 2006; Tung and Zhou, 2013), or a large but random expression of internal variability (Bengtsson et al., 2006; Wood and Overland, 2010)

Nonetheless, these studies do not challenge the AR4 assessment that external forcing very likely made a contribution to the warming over this period. In conclusion, the early 20th century warming is very unlikely to be due to internal variability alone. It remains difficult to quantify the contribution to this warming from internal variability, natural forcing and anthropogenic forcing, due to forcing and response uncertainties and incomplete observational coverage.

How does this square with the authors’ statement that “the second assumption is the conclusion of the IPCC, but disregards the uncertainty surrounding it (IPCC WG1 AR5 Chapter 10)”? Answer: it simply doesn’t. It is not their conclusion. They state that the uncertainties do not permit a quantifiable attribution of warming pre 1950, only that AGW likely made a contribution. In actual fact, numerous recent studies affirm the dominant role in 1910-1940s global warming of the AMO mode of internal variability combined with solar forcing, especially for the Arctic and locations bordering the North Atlantic (which just happens to be the region where the current heatwave is taking place!).

The IPCC statements also blow a hole in the first assumption of the report’s authors, i.e. that the station locations they’re analysing are subject to little decadal variability. The IPCC clearly mention the importance of the AMO which affects precisely this region. Northern European climate is subject to a lot of multi-decadal internal variability, principally by the AMO which has a cycle length of approximately 70 years, which is more than sufficient to have affected temperatures at the specified locations from 1900 to the present! For the avoidance of doubt in this respect:

The Atlantic multidecadal oscillation (AMO) explains over 90% of the pronounced decadal temperature and summer precipitation variation. Understanding the impact of these ocean variations when interpreting long climate records, particularly in the context of a changing climate, is crucial.

[https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.2543]

That rather buggers up the supposedly eminently suitable data from Phoenix Park, Dublin, with regards to demonstrating the probability of extreme weather supposedly unaffected by the presence of natural climate variability, subject only to anthropogenic influences!

The story is not much different for the other locations, all of which are subject to the influence of Atlantic multi-decadal variability.

Thus the two main assumptions of the WWA rapid attribution report are proven false:

  1. The locations used are subject to significant natural multi-decadal/decadal variability.
  2. Anthropogenic GHGs are unlikely to have dominated global warming prior to 1950.

Not good, but that’s not the end of it.

The Observations Disagree With The Models

As mentioned, the analysis uses models to estimate the likely anthropogenic influence. Here’s what the authors say about the model fit vs. data at the various stations:

Dublin Phoenix Park: Only two models had variability compatible with the observations (EUROCORDEX has 30% too much variability but we decided to keep it; EC-Earth is fine but is also downscaled by RACMO, which fits the observations even better). The Risk Ratio is about two in all estimates, the straight average of observations and the two models gives a Risk Ratio of 2.0 with a 95% uncertainty interval of 1.2 …  3.3.

De Bilt: Observations show a much bigger increase in probability than the models, which also show some spreads. We verified that the trend is the same at the other homogenised non-coastal stations in the Netherlands (Eelde and Maastricht). Starting in 1951, and hence avoiding the breaks altogether, gives even higher trends and hence Risk Ratios. The same mismatch extends into Central Europe and has been discussed by Min et al., 2012 and Sippel et al., 2016. The cause is as yet unknown, so the best we can do at this moment is to average these values (on a logarithmic scale) leading to an increase in probability of very roughly a factor three, and definitely larger than one.

Copenhagen Landbohøjskolen: Both models with variability that is compatible with the observations show a somewhat stronger increase than the observed trend, but within uncertainties the results are reasonably compatible (χ²/dof=3.4). The average Risk ratio is roughly five (larger than 2.4).

The Scandinavian stations are even worse:

Oslo Blindern: The observed trend has large uncertainties and is therefore compatible with both models that have realistic variability. The two models with realistic variability agree well. The average gives a Risk Ratio between 1 and 10, so we can say that the probability increased but not very well by how much.

Linköping (Sweden): Again there is huge uncertainty in the observed trend. The EUROCORDEX ensemble has a higher trend than the other two models, so we cannot say much more than there is definitely an increase in probability for heat waves.

Sodankyla: In the high Arctic, the uncertainties both on the observations and on the climate models are enormous. Given the strong positive trends in the climate models, and the possibility of a positive trend in the observations, we can state that the trend is positive but nothing more. Note that the scale extends over eight orders of magnitude.

Jokioinen: The same holds for the more southerly station in Finland.

The authors explain the rationale behind choosing individual stations, even though the mismatch between observations and models is plainly a problem. Basically, it’s because real people live in these locations, not statistically spread out across wide regions, so the attribution result is more pertinent!

In our analysis we have looked at local weather stations in northern Europe where people are experiencing the heat wave today. In individual locations the interannual variability in summer temperatures is much larger than if we would average over countries or the whole region that is experiencing a heat wave in the early summer of 2018. The climate change signal is thus harder to detect from the noise in individual places. However, it is towns and villages where people live and not area averages, hence we chose to focus on stations only in this analysis.

In summary, here is what the authors have to say about the observations and the models for the particular locations used in their attribution study:

In Ireland, the Netherlands and Denmark there are clear trends towards more heat waves in the observations. In Ireland and Denmark climate models give a very similar increase in probabilities to the observations — roughly a factor two more likely in Dublin and a factor four in Denmark. In the Netherlands the observed increase in hot extremes is much larger than the modeled increase. This is a well-known problem (Min et al, 2013, Sippel et al, 2016) but the cause has not yet been elucidated.

However, this is not the case further north. No trend is currently detectable in the observations there. However, due to the large variability of the summer weather, the uncertainty in the trends is so large that the observations are also compatible with large changes in the likelihood of heat extremes to occur. In the case of Scandinavia, the models are thus probably a better source to estimate the change in likelihood as we have large ensembles of model experiments.

Does all this inspire much confidence in the use of these models and observations combined to attribute the influence of anthropogenic climate change upon the 2018 heatwave in Europe and Scandinavia?

Does it inspire much confidence in this Guardian headline, outlining the results of this rapid attribution study?

Heatwave made more than twice as likely by climate change, scientists find

Fingerprints of global warming clear, they say, after comparing northern Europe’s scorching summer with records and computer models

I have to say: no, it bloody well doesn’t! But, as usual, it’s out there now, all across the media airwaves; climate alarmists everywhere are saying ‘the science is in – climate change did cause the 2018 northern European heatwave’. 99% of them probably haven’t even bothered to read the actual study which purports to be ‘the science’.

Those of us who do not leap at the opportunity to believe in the magic science of extreme weather attribution will note the massive and unexpected cooling in the tropical and Northern Atlantic this year and question whether this has had any influence at all upon the concurrent heatwave in northern Europe. Joe Bastardi has an excellent Patriot Post article on exactly this.

Update: 08/07/2019

What a difference a year makes:

North West US/Canada Pacific Heatwave: The Climate Alarmist Waffle Begins As We Await ‘The Science’

I’m holding back on saying too much about the recent brief but extremely intense heatwave in Oregon and other NW Pacific coastal areas. It was a remarkable and ‘unprecedented’ meteorological event for sure. Not only record breaking temperatures (reference last century) but record breaking rapid cooling too – which I’m sure the climate change hysterics won’t be pointing out nearly as frequently as they do gasp with a mixture of barely concealed wild excitement and pro-forma alarm at the ‘unbelievably’ high maximum daytime temperatures. Here’s what Cliff Mass (meteorologist, not climate alarmist) has to say:

It’s over.   

Throughout the region, all-time temperature records have been broken, if not smashed.   Just to name a few:

SeaTac hit 108F, beating the previous record of 103F.

Olympia reached 109F, exceeding the previous record of 105F

Quillayute, on the WA coast, zoomed to 110F, absolutely smashing the previous record of 99F

Portland hit 116F, incinerating the previous record of 107F.

In eastern Washington, Dallesport tied the all-time state record of 118F

East of I5, many locations in western Washington exceeded 110F yesterday.

But we had not only had extreme heat….far beyond that observed over the past century… but also record-breaking cooling as a thin layer of marine air surged in last night.

Portland cooled by 52F (116 to 64) and Salem by 56F (117 to 61) in a matter of hours.
Seattle cooled by an impressive 46F!
Quillayute by 48F.

The visible satellite imagery this morning showed that marine clouds not only covered the coast but pushed inland around the Olympics.

To get the lowdown hype from the climate alarmists, we need only go to Inside Climate News who shout excitedly:

Global Warming Cauldron Boils Over in the Northwest in One of the Most Intense Heat Waves on Record Worldwide

As residents prepare for even more temperature records to fall in the heat dome forecast to persist for days, scientists see a heavy climate change fingerprint.

Well, it ‘persisted’ for two days and it’s now over, but ‘scientists’ can already see a ‘heavy climate change footprint’ apparently. Really? Wow, that was fast, especially as the heatwave was still actually happening at the time the article was written! My goodness. So where is this Sasquatch-like climate change footprint then?

Here?

In a Twitter thread over the weekend, Ben Noll, a meteorologist with the New Zealand National Institute of Water & Atmospheric Research, reported that Portland, Oregon would be hotter than 99.9 percent of the rest of the planet on Sunday. “The only places expected to be hotter: Africa’s Sahara Desert, Persian Gulf, California’s deserts,” he tweeted. 

Or here?

The intensity of the heat wave, measured by how far temperatures are spiking above normal, is among the greatest ever measured globally. The extremes are on par with a 2003 European heat wave that killed about 70,000 people, and a 2013 heat wave in Australia, when meteorologists added new shades of dark purple to their maps to show unprecedented temperatures.

And the more extreme the temperature records, climate scientists said, the more obvious the fingerprint of global warming will be on the heat wave. But even among climate scientists, the biggest concern was the immediate impacts of the record shattering temperatures.

Is this getting warmer?

The current Western heat wave is remarkable by almost any standard, said University of Reading climate scientist Chloe Brimicombe. But such events are becoming more common, to a large degree because of the 1.2 degree Celsius global average temperature increase since the industrial revolution has pushed the heat wave needle into the red zone, she said. 

“Heat waves are our alarm system for the climate emergency,” she said. “If there are more heatwaves, our emergency is getting worse.”

Or, surely, here? This sounds much more sciency:

Karin Bumbaco, a research scientist at the University of Washington who serves as Washington’s assistant state climatologist, called climate change attribution “a really great question, and it is one that’s hard to answer.” She said it won’t be possible to tease apart how much natural variability and how much man-made warming can be blamed for the current Northwest heat wave until scientific studies examine what happened, which typically takes months or years. 

“But, you know, even without that being done, it’s a safe assumption, in my view, to blame increasing greenhouse gases for some portion of this event—Washington state is warming, the Pacific Northwest is warming, globally we’re warming,” she said. “As we shift that baseline, we’re going to see more and more of these extreme events.”

Well, it was sounding all sciency and dutifully cautious, but then she threw science and caution to the wind in the second paragraph by going full ‘Alf Garnett’ on her attribution statement, i.e. “It must be climate change – It stands to reason, don’t it”.

But the prize for the kookiest, most bizarre attribution goes to Gavin Schmidt:

For climate scientist Gavin Schmidt, director of the NASA Goddard Institute for Space Studies, the Pacific Northwest extreme heat is shocking. He said on Twitter that scientists will find a clear global warming fingerprint on the heat wave, with the exact influence of global warming linked with how hot it gets.

“And the hotter it gets,” he said, “the larger the attribution will be.”

He knows, even before it happens, that scientists will find a global warming fingerprint on this heatwave – cos the hotter it gets, the larger the attribution will be. So we don’t really need science, do we, when looking at extraordinary heatwaves like this, because the scientists are sure that it was the climate crisis wot dunnit, even before said extraordinary events are over.

OK, enough of the funnies. A formal attribution study is currently in progress, analysis to be completed by scientists at World Weather Attribution:

Scientists with World Weather Attribution have already launched a study to identify how global warming intensified the Pacific Northwest heat wave, with initial results expected in early July, said Geert Jan van Oldenborgh, a climate scientist with Royal Netherlands Meteorological Institute, who has co-authored several previous climate attribution studies.

That research could help explain a worrying trend. In some regions, like northwestern Europe, heat waves in the last 20 years have become warmer about twice as fast as many climate models project, “and we don’t know why,” he said.

Catch the last paragraph? Climate models fail to explain why maximum daytime temperatures in recent heatwaves have been so high. I’ve pointed this out before:

In the Netherlands the observed increase in hot extremes is much larger than the modeled increase. This is a well-known problem (Min et al, 2013, Sippel et al, 2016) but the cause has not yet been elucidated.

In the Northwest heatwave for instance, previous records have been completely obliterated. A regional secular warming trend of a degree or two cannot explain these extremes. It has to be down to weather and that means meteorology: dynamics, not thermodynamics (global warming). In order to attribute these extreme events to global warming (thermodynamical influence), you also have to explain how dynamical influences have been so altered by generalised global warming that they are capable of producing such ‘unprecedented’ extremes in temperature. You also have to be very careful to eliminate other possible contributory factors to extreme temperatures such as preceding drought conditions, land use changes and urbanisation. So, I’ll wait until the formal attribution study is published by WWA and then comment.

Photo credit: Inside Climate News

Addendum: Event definition

WWA have an article entitled ‘Pathways and Pitfalls in extreme event attribution’. They point out that the definition of the extreme event is very important in determining the result of the attribution. Defining the event is very much a choice of the people doing the analysis.

Defining the event turned out to be both much harder and more important than we thought when we started attribution science. As an example: the first published extreme event attribution study analysed the extremely hot summer of 2003 in Europe (Stott et al, 2004). It took as event definition a European-wide seasonally averaged temperature, whereas the impacts had been tens of thousands of deaths in the 10-day hottest period in cities. A large-scale event definition like a continental and seasonal average has the advantage that climate models can represent it better and the signal-to-noise ratio is usually better than a local, short time scale definition. However, it is not the event that caused the damage and in WWA we try to relate our attribution question to the impacts, so we usually choose a definition of the event that corresponds as closely as possible to the impacts.

It’s almost certain that WWA will choose to define this extreme event only with reference to extreme daytime temperatures in the regional Pacific Northwest, but it’s a fact that record low temperatures have also occurred in the east of the US as a result of the configuration of the jet stream. The two are dynamically linked. So in actual fact, the extreme weather might be said to be occurring across the entire continental US, not just in the Pacific Northwest.

Update: 6th July 2021

Cliff Mass has an excellent post here arguing convincingly why the NW Pacific heatwave was not due to global warming and was in fact a ‘black swan’ weather event. He also lays into those deliberately peddling misinformation about this heatwave for purely political ends:

Politicization and Miscommunication of Science
The inaccurate information being distributed about the origins of this heatwave is very disturbing.
Some of this is being done out of ignorance or laziness, but a few individuals are deceiving the public deliberately.   Science journalism is only a shadow of what it was decades past, and a number of scientists now see social activism as more important than the determination and communication of truth.
Our nation has made costly mistakes when the truth was twisted for political reasons, such as for the Iraq war, when our nation spent trillions of dollars and initiated a war that killed hundreds of thousands of people based on misinformation about non-existent weapons of mass destruction.
We are now making similar mistakes with global warming, with politically inspired misinformation slowing realistic and life-saving steps, such as thinning our forests and restoring natural fire, or proceeding rapidly with nuclear energy.  Hyping global warming puts unrealistic and unnecessary fear into the hearts of our fellow citizens.  Unconscionable.  Global warming is an issue we can deal with, but only if truthful, factual, and science-based information is provided to decision-makers and the nation’s citizens.
I have spent my life trying to understand the weather and climate of our region and it is so frustrating that the media (e.g., KNKX public radio, the Seattle Times, the Seattle Stranger) and local politicians (such as our governor) have placed such a low priority on providing accurate information regarding climate change and other environmental challenges.  
They have put political agendas ahead of truth and we are all the worst for it.

Couldn’t agree more. This is what we are up against and it’s going to get worse.

April 2021 – Coldest Average Minimum CET Since Records Began

If you live in Central England and you thought the nights were exceptionally chilly last month, for April, the second month of Spring, then you would be right. There were numerous frosts throughout the month. I woke up to a hard ground frost on the east coast on St George’s Day and the grass was still frosted in the shade even hours after sun up. The days were cold too, but the nights were something special. So special in fact that April 2021 earns first place by a considerable margin for the coldest average April min CET since records began in 1878. April 2021 min CET = 1.0C. The next coldest April is 1917 at 1.4C, nearly half a degree warmer! That is really quite remarkable. April 1986, in terms of mean diurnal CET, was colder than April 2021 (5.8C vs. 6.4C) but the nights in 1986 were a lot warmer (2.2C vs. 1.0C), even though the days were colder. This undoubtedly comes down to the fact that April 2021 was also very sunny throughout the UK, raising daytime tempertures, but allowing them to plummet in the relentless northerly airflow, which brought cold air from the Arctic over the British Isles throught the entire month.

For the UK as a whole, the Met Office says that April 2021 saw the coldest average minmum temperatures for nearly 100 years:

April 2021 had the lowest average minimum temperatures for April in the UK since 1922, as air frost and clear conditions combined for a frost-laden, chilly month, despite long hours of sunshine.

It was very sunny:

Despite the low minimum temperatures and frosts, much of the UK has been basked in sunshine through April, with all UK countries currently reporting sunshine hours for the month in their top five ever recorded since 1919. This has provisionally seen Scotland and Wales break their existing records for sunshine hours in the month, with the two countries seeing 57% and 45% more sunshine than their long term averages. For Scotland, this would represent the second year running that April’s sunshine hours have broken the existing record, with 2021’s current figure of 211.5 topping 2020’s 204.6 to top the standings.  

The final figures for 2021 don’t appear to be in yet, but April 2021 is definitely challenging 2020 as the sunniest month on record.

Currently the UK is experiencing its second sunniest April on record, with 218.8 hours. As the figures won’t include today’s sunshine totals, there is scope for this figure to rise further, potentially challenging the April record set last year with 224.5 hours. The UK saw 48% more sunshine hours than April’s average figure, and every country in the UK saw at least 40% more sunshine than the long-term average. 

The irony here is that last year’s very sunny April – when the murderous sociopath Matt Hancock banned sunbathing and was threatening to ban all outdoor exercise for everyone because of a nasty bug going round – was also very warm, unlike this year of course. That was inevitably linked to climate change. Dr. Mark McCarthy, for example, wasted no time identifying a trend of warm Aprils due to the UK’s changing climate:

Dr Mark McCarthy is the head of the Met Office’s National Climate Information Centre. He said: “Although April 2020 will be remembered for being the sunniest April on record in England and the UK, along with the sunshine, the month was largely dry with mean temperatures well above average for most parts of the UK. The UK climate is warming, and it is notable that in a Met Office series from 1884 the Aprils of 2003, 2007, 2009, 2011, 2014 and 2020 are all in the top ten warmest.”

Strangely though, he hasn’t done the same this year! Global warming in the UK works in mysterious ways. It makes April sunnier and sunnier, and warmer and warmer, until suddenly it doesn’t and instead it makes April nights the coldest ever recorded going back to 1878, with the days not much better. Of course, real meteorologists know that the clue to this apparently bizarre weather is the changing spring jet stream configuration over the British Isles (and possible decadal trends in that configuration); atmospheric dynamics rather than simple thermodynamics. However, the all-singing, all dancing climate models don’t have much to say about that.

Jennifer Francis: The Cold Weather Affecting The Eastern US now is Global Warming – ‘It’s Inevitable But Mysterious’

Each year that the US gets severe cold weather (which has happened a lot over the past 20 years), there’s always a few climate change fanatics who claim that it’s due to global warming. They have to you see. Snow, ice and severe cold are bad for business. It wasn’t supposed to be like this. Winters were supposed to get warmer, shorter, spring was supposed to arrive earlier and summers were meant to be searingly hot. Severe cold weather at the end of January doesn’t fit the narrative, so they change the narrative. Simples.

I recall the good old days, when President Trump was around to troll the climate change fanatics with tweets like this:

In the East, it could be the COLDEST New Year’s Eve on record. Perhaps we could use a little bit of that good old Global Warming that our Country, but not other countries, was going to pay TRILLIONS OF DOLLARS to protect against. Bundle up!

— Donald J. Trump (@realDonaldTrump) December 29, 2017

They went into hysterics of course, on that occasion claiming that it was ‘just weather’ and that Trump was using ‘just weather’ to ridiculously claim that global warming wasn’t happening. ‘Experts’ and the Guardian laid into him lie a pack of hyenas:

US president again conflates weather with climate to mock climate change

Experts call comments ‘scientifically ridiculous and demonstrably false’

The president was reheating two favourite tropes: the conflation of weather with climate to pour scepticism on global warming, and the supposed cost to the American taxpayer of the Paris climate accord, from which he has confirmed the US will withdraw.

Climate scientists, however, have long warned against using individual weather events to ponder the existence or otherwise of global warming. Weather, they point out, refers to atmospheric conditions during a short period; climate relates to longer-term weather patterns.

“There is a fundamental difference in scale between what weather is and what climate is,” he said. “What’s going on in one small corner of the world at a given moment does not reflect what’s going on with the planet.”

But severe (often record breaking) cold weather has been happening so frequently, particularly in the eastern US, that climate change fanatics are now having to admit it’s not ‘just weather’ after all, as they previously shrieked and screamed in response to being trolled by Trump, it’s actually a bizarre and counter-intuitive result of global warming. Yep, the new global warming is . . . . . . cooling!

Hence, with Bidet now in charge, who made it his first task on day one of his fake Presidency to sign the US back up to the Paris Accord, and the upcoming COP26 meeting in Glasgow, climate alarmists are keen to keep the man-made global warming narrative going, even during severely cold winter weather.

So the NYT, noting the present cold weather in the US, has once again wheeled out Jennifer Francis along with her theory of how Arctic warming causes extreme weather, a theory which has been doing the rounds for several years now, which has been severely criticised by scientists, has little real evidence in its favour, but is all they’ve got, so they keep regurgitating it to explain inconveniently cold and snowy weather.

Disturbances to the upper-atmosphere phenomena known as the polar vortex can send icy blasts from the Arctic into the middle latitudes, chilling Europe, Asia and parts of North America. The disturbance and its effects have persisted for an unusually long time this year, said Jennifer Francis, a senior scientist at the Woodwell Climate Research Center, with two disruptions of the polar vortex so far this year and, potentially, a third on the way.

Research into the interplay of the complex factors that bring on blasts from the polar vortex is ongoing, but climate change appears to be part of the mix. While warming means milder winters overall, “the motto for snowstorms in the era of climate change could be ‘go big or go home!’ said Judah Cohen, director of seasonal forecasting at Atmospheric and Environmental Research, a company that provides information to clients about weather and climate-related risk.

The wild weather has its origins in the warming Arctic. The region is warming faster than the rest of the planet, and research suggests that the rising temperatures are weakening the jet stream, which encircles the pole and generally holds in that frigid air. In early January, a surge of sudden warming hit the polar stratosphere, the zone five to thirty miles above the surface of the planet.

But it’s not clear cut, as the NYT itself admits:

While the scientific evidence supporting climate change is indisputable, the connection between climate change and the disruptions in the stratosphere is not so settled. Dr. Cohen was an author of a paper last year in the journal Nature Climate Change, which looked at winter data from 2008 to 2018. The team found a sharp increase in Northeast winter storms over the previous decade. “Severe winter weather is much more frequent when the Arctic is warmest,” Dr. Cohen said.

Dr. Butler, however, said that across the full historical record, which goes back to 1958, “There is no indication of a long-term trend” in polar vortex disruptions. The weather patterns that affect the vortex “occur naturally even in the absence of climate change,” with some decades showing no disruptions and other decades with one in almost every year.

But Jennifer Francis is having none of it. There simply must be a connection she states; we just haven’t discovered it yet:

To Dr. Francis, a senior scientist at the Woodwell Climate Research Center, the influence of climate change on these phenomena is inevitable, if still somewhat mysterious. “We’re changing the planet in such dramatic and incontrovertible ways,” she said. “The atmosphere is different now. The Earth’s surface is different now. The oceans are different now. So there must be some connections that are yet to be discovered as we do more research on the stratospheric polar vortex.”

This is climate science for you. This is extreme weather attribution. If the data doesn’t fit the theory, if the theory fails, then just invoke the climastrologists’ Inevitability Principle, which states:

A must cause B, even though there’s no evidence that B is caused by A, simply because A ‘changes everything’ and A is ‘settled science’.

Richard Betts Finally Gives Up On Science – Embraces Politics, Ideology and Pseudoscience

Over the years, Richard Betts of the Met Office, has been the ‘sceptic’s friend’; a down to earth, reasonable, approachable, pragmatic scientist who actively sought to present a balanced view on the risks associated with climate change and to counter the alarmism and hyperbole put out in the press and supported by some of his more enthusiastic peers, as well as overtly political climate activists. Sadly, he has now jumped the shark completely, even to the point of insulting sceptics by implying that they are ‘deniers’, a term he always refrained from using. He’s even, by the sound of it, helping Extinction Rebellion fanatics arrested for breaking the law defend their actions in court by providing them with scientific ‘evidence’ which supposedly justifies their unlawful activities.

So Richard thinks that extreme weather attributions are helping to put a dent in climate denial and prove the case for urgent political action and planning and adaptation policies. In his article for Nature he says:

Now that specific floods, heatwaves and more can be attributed to our actions, decision makers can act.

This is not true. No specific extreme weather event can be attributed definitely to man-made climate change; all that can be done is to calculate the the so-called fraction of attributable risk of such an event happening by using climate models with and without anthropogenic forcings to create two ‘worlds’ and estimating the likelihood of such an event happening in the ‘climate changed’ world compared to that of the hypothetical world where no anthropogenic forcings are present. A further estimate of likelihood is also obtained by examining historical weather records for evidence of similar extreme weather events and assessing their frequency of occurrence over years and decades. What these ‘scientists’ then come up with is a figure for the supposed increased probability of such and such an event happening due to man-made climate change.

Betts knows this, but he deliberately misleads his gullible Twitter followers and readers.

These are just a few of the specific heatwaves, floods and events that my colleagues who work on ‘climate attribution’ can now show were made more likely by human impact (these and more are showcased this week in a special issue of Bulletin of the American Meteorological SocietyS. C. Herring et al. Bull. Am. Meteorol. Soc. 102, S1–S112; 2021). Now, these techniques should be applied routinely to help governments, organizations and communities to act on their responsibilities and improve resilience to extreme weather.

For too long, weather’s randomness has kept events such as these from being blamed squarely on climate change.

He goes on to directly contradict himself by then saying:

Now, we can specify increased chances for specific events. This extends to forecasts: we can identify the places that are more likely to see wildfires, mudslides and fish die-offs. Such calculations dent both climate denial and a false sense of security. They take away the argument that ‘extreme weather happens anyway, so we don’t need to worry about it’. Extreme weather happens — and these metrics pinpoint what is becoming more likely, by how much and why.

You cannot blame a particular weather event squarely on climate change if all you are able to do is give an estimate of the increased probability of such an event happening. That is not ‘attribution’; it is guesswork based upon an assumption that the atmosphere and oceans have changed mainly because of the addition of man-made GHGs, using biased climate models to quantify that change and to compare it with a counterfactual world where no GHGs were released into the atmosphere.

As mentioned above, Betts also clearly thinks that this ‘scientific evidence’ of attribution is good enough to present to a court in defence of climate crisis fanatics who claim their lives and futures are being put at risk by government inaction on climate change.

Such evidence is also useful for legal proceedings when citizens call corporations or governments to account for their role in climate change, or are on trial for taking the law into their own hands. Although the courts, not climate scientists, make judgements on these matters, the legal process needs to be informed by objective, authoritative scientific evidence; published, peer-reviewed science is crucial. I relied on this to provide an expert-witness statement for the trial of an Extinction Rebellion activist arrested after obstructing the main road on Waterloo Bridge in London. For a case against 33 European countries brought by 6 Portuguese youth applicants, the non-profit science and policy institute Climate Analytics prepared an expert report (see go.nature.com/3qmv) centring on the evidence for climate change’s rising threat to their lives.

So, let’s take just one brief look at this latest peer-reviewed evidence which Betts thinks provides the scientific framework for holding governments to account and putting climate deniers back in their box shall we.

On page 44 of the report cited above by Betts, we find an attribution analysis of the extraordinary warmth which affected the UK in February 2019, when temperatures exceeded 20C in some places of the country. It is authored by Nikolaos Christidis and Peter A. Stott.

In stark contrast to the frigid close of the 2017/18 winter in the United Kingdom (Christidis and Stott 2020), daytime winter temperatures above 20°C were recorded for the first time in the country only a year later, with a maximum of 21.2°C at Kew Gardens on 26 February 2019. Strong anticyclonic conditions at the end of the winter season steered exceptionally mild tropical maritime air over western Europe and were identified by Kendon et al. (2020) as a key driver of the extreme U.K. temperatures. Their study suggests that the atmospheric state alone would be sufficient to raise U.K. temperatures above 20°C, even without the effect of human influence on the climate. Here, we carry out a complementary attribution study to investigate extremes in the warmest day in winter.

What they are in effect saying here is that the actual cause of the extreme temperatures has been identified as a peculiar dynamic weather pattern at the time but that they intend to do another attribution study anyway just to see if ‘climate change’ might have increased the chances of such extreme temperatures if natural weather patterns had not been the actual cause of the event! This attribution study, they make clear, does not take into account possible changes in dynamics forced by GHGs. It only considers thermodynamic (GHG) forcings. Thus, in attempting to provide an alternative attribution of the warm UK weather in February, it completely ignores the actual cause of that warm weather. This is apparently what Betts considers as a good example of the scientific ‘evidence’ for climate change impacts, good enough to present to a court of law. Any decent defence or prosecution lawyer would laugh it out of court!

The CMIP5 analysis reveals that winter CET extremes like in 2018/19 are rare even in today’s warmer climate, but still about 300 times more likely because of human influence. Moreover, they are shown to become decidedly more common in the future, expected to occur at least once a century by 2100, and probably more frequently underhigher emissions scenarios than RCP4.5. While the effect of the atmospheric circulation was key for the reference event, here we only consider an unconditional framing without explicitly assessing the effect of dynamics. Previous work has suggested that Arctic warming may impact U.K. extremes via dynamical changes (Hanna et al. 2017), although this link has not been robustly established (Blackport and Screen 2020). A possible strengthening of the Atlantic jet (Lee et al. 2019) may constitute another dynamical driver of winter changes. Taking the overall effect of anthropogenic climate change into account, milder winters are expected in the United Kingdom (Murphy et al. 2018), with less frequent cold extremes and new high temperature records.