July 26, 2021

expert reaction to study modelling probability of record-breaking heatwaves

A study, published in Nature Climate Change, looked at the probability of record-breaking heatwaves occurring.

Dr Karsten Haustein, Climate Service Center Germany, said:

“It is one of those papers which couldn’t be any more timely in light of the recent record-shattering extreme heat event in the US and Canada. Almost as if the authors foresaw what’s coming. Combining different observation and model based climate data, they found that heat waves which not just exceed, but shatter old records become multiple times more likely (up to 20 times between 2051-2080) if we fail to drastically reduce our carbon emissions. Take, for example, an extreme heat wave which only occurs every once in a century. It would have been a hot and dangerous weather episode in any climate. But if it happens to occur in a world that has warmed by 2-3°C during the past 100 years, it will suddenly lead to an unprecedented heat wave which has the potential to shatter old records by 5°C or even more. Taking the spatial extent into account, the authors found that such event could occur every ~20 years somewhere in the mid-latitudes of the northern hemisphere in the 2nd half of this century.”

Prof John King, climate scientist at the British Antarctic Survey, said:

“Last year we saw record high temperatures across the Eurasian Arctic, and a new Antarctic record temperature of 18.3°C set at Esperanza station. This new study demonstrates that extreme, damaging events such as these will rapidly become more common in a warming climate, emphasising the urgency for action to be taken at COP26 to reduce carbon emissions and limit climate change to safe levels.”

Prof Rowan Sutton, National Centre for Atmospheric Science, University of Reading, said:

“Recent events such the exceptional heat wave in North America and flooding in Europe have highlighted the devastating effects of extreme weather amplified by climate change. This new study shines a valuable spotlight on the high potential for record-shattering extremes.  This high potential is a consequence of the extraordinary rate of climate change: whilst it may not seem rapid to us, Earth is warming at a rate that is unprecedented in the history of human civilization. 

“The authors of this study show that this very rapid warming means we must expect extreme event records to be broken – not just by small margins but quite often by very large ones.  This highlights the huge challenge to improve preparedness, build resilience and adapt society to conditions that have never previously been experienced.  COP26 negotiators: take note.”

Dr Vikki Thompson, Senior Research Associate at the University of Bristol, said:

“Just in the last month, the world has experienced temperature records being smashed in North America and devastating floods in Europe and China. It is clear that climate change is affecting the planet. The need to understand what could happen in the future is vital to allow us to adapt. 

“This new study shows we should expect more heatwaves which break records by large amounts as seen last month in North America. It finds that these extremes were nearly impossible without global warming. The study shows that with a reduction in emissions the magnitude of extremes quickly reduces. 

“The good news is that we can prevent the worst case shown in this study – we are already on target to be below it and further reductions in emissions will reduce the risk of unprecedented extremes further. Studies like this show the need for clear global emissions targets, which could come out of COP26.”

Prof Tim Palmer, Royal Society Research Professor at the University of Oxford, said

“This is a very important study. However, current generation climate models do not have adequate resolution to simulate the record-shattering events that have been observed this year in North America and Europe: neither the actual temperatures nor the actual rainfall amounts in these observed events are close to being simulated in the models.

“We need to develop a new generation of ultra high-resolution global models to get an accurate picture of how the observed records will be broken as we progress through the coming  years and decades.  Many of us believe that this is only possible by creating a new international centre where human and supercomputer resources are pooled and focussed on the prediction of extreme climate risks.”

Dr Cathryn Birch, Associate Professor in Meteorology and Climate at the University of Leeds, said:

““The recent North American heatwave, which was far more extreme than people in the region had ever experienced before, is a prime example of the record-shattering events discussed in this study.”

“The important new finding here is that temperature records tend to be shattered during periods of accelerated global warming. Even though global warming of more than 1C has already occurred and heat extremes have increased as a consequence, if we act now to reduce greenhouse gas emissions we have the opportunity to reduce the chance of routinely breaking extreme temperature records in the future.”

‘Increasing probability of record-shattering climate extremes’ by E. M. Fischer et al. was published in Nature Climate Change at 4pm UK time on Monday 26 July 2021.

DOI: 10.1038/s41558-021-01092-9

Declared interests

Dr Birch: “nothing to declare.”

Prof King: “no conflicts.”

None others received.