North West Heatwave

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)

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?


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.