Posted on July 25, 2022

Post by Professor Dan Osborn, Chair of Human Ecology, Earth Sciences, at UCL (University College London, UK) and Editor-in-Chief of the UCL Press journal UCL Open: Environment

In June 2021, when the evidence report for the 3rd UK climate risk assessment (CCRA3) was released, talk was of southern England summer temperatures over 40°C being experienced sometime “before 2050” (Baroness Brown in launching the evidence report) and in the detail the message of the Technical Report seemed to be that the chances of 40°C before 2040 was small. 

Events have now overtaken these projections. 40°C came to the UK in mid-July 2022, just a year after the launch of the CCRA3 work and 2 years after the UK heatwave of 2020 was linked to over 2,000 excess deaths. Is there some readily available consistent context for this that people can look at so they can have some evidence on which to base their views and decisions? The BBC runs a service for the public to discover how hot it could get in their area of the UK under climate change. It is based on climate modelling. Some of the temperatures recorded in the last few days in the UK don’t feature in the results from the BBC tool even for a world where 4 degrees of warming occurs. The results for Coningsby in Lincolnshire where the new UK record temperature (40.3°C) was provisionally recorded are interesting: warmest summer of past 30 years: 34.9°C; projected figures for the future under 2 degrees of global warming: 37.1°C; and only under 4 degrees of global warming do we get close to what happened a few days ago: 40.2°C. Now, the BBC has a tool for extreme heat vulnerability, and even though this is based on 3 years’ worth of data analysed by a consultancy, it represents an interesting development in public information provision. And so far – on average – the world has warmed a little more than 1°C.

Right now, the UK is reflecting on an event where the previous high temperature record was simply busted by over 1.5 degrees and record temperatures were recorded not just in one place in southern England but in places as far north as North Yorkshire and, in the provisional data, at 39 separate locations. On top of this, night-time temperature records were also broken along with records for Scotland and Wales for both day and night. This was a really very exceptional event. Of course, the UK is not alone in experiencing these high temperatures as the data and mapping from many agencies, including that of the ECMWF (https://www.ecmwf.int). Wildfires across Europe, including in the UK, have led to deaths, injuries and destruction of property and are the most obvious dramatic impact of a European wide heatwave.

The climate model results all point in the right direction – they just did not, it seems as far as readily available public evidence has been concerned, reached the exceptional heights of the temperatures experienced although the weather modelling for the public was remarkably accurate. This is not particularly surprising as near-term projections will almost inevitably be more accurate than ones in the mid to far future. Quite possibly, the high temperatures were in the model outputs but just residing in the extreme tails of the distribution of the results.

So, maybe, more attention is needed to the tails of model projections so that potential extremes can be built into emergency planning, engineering designs, homes and lifestyles and, maybe, even the best climate models need to be improved in the challenging area of the extremes or the way their outputs are communicated. Other improvements to the processes of climate change work might also be needed.

There is, it seems, also a tendency towards conservativism in some climate change work in international and national fora driven by the need to strike that delicate balance between what the science might indicate and what is possible in both the policy and the political arenas. This issue came to the fore most recently when the COP26 agreement included that infamous ill-defined phrase about phasing down unabated coal - which really gets a lot of people off the hook in terms of cutting fossil fuel emissions anytime soon.

Perhaps the balance needs to shift towards the extremes the science points to as well as the long-term trends. Maybe also, the language of average global temperature rises has been in play too long and now is the time to be more local and make clear that people’s local experiences are going to be very different and sometimes very far from the average. Our language, our behaviour and our legal frameworks need to take account of what evidence is on real temperatures, real rainfall (and the lack of), and real-world problems such as new buildings that are just not ‘climate ready’.

Some will say it would be wrong to base actions on just one set of extremes, but the point is that the UK’s recent experience is just one set of extremes amongst many. There is a point at which what was extreme starts to look like an unpleasant norm. The world simply cannot afford the consequences of our changing climate. They are simply not sustainable in social, economic or environmental terms. Some 16 years after the Stern Report these facts must be faced by everyone. Finding a way through the challenges means acting fast and with the urgency evident in much of the CCRA3 reporting on risks that needed to be immediately addressed.

About the author

Professor Dan Osborn is Chair of Human Ecology, Earth Sciences, at UCL (University College London, UK) and Editor-in-Chief of the journal UCL Open: Environment (https://journals.uclpress.co.uk/ucloe/), published by UCL Press.

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