Met Office

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.

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.