The future of heatwaves

Posted in: COP26, Energy and environmental policy

David Coley is Professor of Low Carbon Design and Head of the Energy and the Design of Environments research centre at the University of Bath.

There are several challenges in communicating the likely impact of climate change. In much of the world the suggested uplift in mean temperature will be seen by many as mild.

This is because most of us have little idea of the small differences in means that underlie very large differences in weather, flora, fauna, agriculture and energy demand for cooling or heating. For example, a 2 to 4°C rise in mean temperature, which is in line with many climate predictions, might seem of little concern - until this is compared to the observation that the mean temperature difference between London in the UK and Nice in the Mediterranean is only 5°C. Once this is realised, the magnitude of the changes and their impacts on us and the landscapes around us become far more apparent.

Although most of us have a poor understanding of the seasonal means where we live, we do have a visceral feeling for the weather (i.e., the daily or hourly time series of temperatures, etc). Hence there is some logic in not only presenting climate change as a change in climate but as a change in weather. After all, a common refrain might be “what’s the weather looking like this week?”, not “what’s the climate looking like this year?”

One of the most worrying aspects of climate change is the expected progression in extreme temperatures. For human survival, and as clearly demonstrated by the Paris heatwave of 2003 where 14,000 died, periods of higher than typical temperature will be particularly challenging.

In the Department of Architecture and Civil Engineering at the University of Bath, we have been trying to create example weeks of future weather during atypical, but not unrealistic, periods of high temperatures.

The figure below shows some of the results. The maps show how the maximum daily temperature averaged over seven days during a heatwave that might be expected to occur once every 20 years during the 1970s, and then during the 2080s. This is a transformed world compared to the one many of us grew up in and our buildings were designed to cope with.

Daily maximum temperature averaged over a typical heatwave week for the 1970s (left) and the 2080s (right).

It is clear we can expect events like the Paris heatwave in the UK, and potentially a similar number of deaths in the future, unless we start to develop a strategy – one in which we can ensure homes can withstand such heatwaves.

Discussions at COP26 and beyond also need to further focus on, and emphasise, the scale and danger of these short-term events, rather than mean changes in temperature. Recent wildfires across the world have drawn attention to this, but we need collective action – from experts and the press, to climate negotiators and world leaders - to help everyone further understand the dangers ahead.

This work is funded in part through the EPSRC’s Active Building Centre (EP/S016627/1) and EPSRC’s COLBE (EP/M021890/1) project. Contact Professor David Coley to learn more about this research.

All articles posted on this blog give the views of the author(s), and not the position of the IPR, nor of the University of Bath. Read more of our blogs on COP26.


Posted in: COP26, Energy and environmental policy


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