Climate change made France’s heatwave at least five times more likely, say researchers

June 2019’s heatwave broke all-time temperature records across Europe. Focusing particularly on France in the centre of the heat wave, a group of scientists at the University of Oxford and other institutions found that such heat was made at least five times more likely by climate change.

The analysis was published in a report by World Weather Attribution, an initiative of university and government climate scientists across the world looking at the influence of climate change on extreme weather events and led by Oxford’s Professor Friederike Otto and Dr Geert Jan van Oldenborgh at KNMI in the Netherlands. Amongst many others the analysis used weather@home, a series of regional climate modelling experiments within climateprediction.net, which uses citizen science to run climate models on thousands of home computers. Climateprediction.net is a collaborative project between the Centre (led by Professor David Wallom), the Environmental Change Institute and other Oxford departments.

The researchers also analysed temperature records stretching back to 1901, to assess the probability and intensity of a heatwave now and in the past. The observations indicated a large increase in the temperature of June heatwaves in both Toulouse and France as a whole. Currently such an event is estimated to occur approximately every 30 years, but similarly frequent heatwaves would have likely been about 4ºC cooler a century ago.

Acting Director of the Environmental Change Institute, Professor Friederike Otto, said that the findings gave the most conservative assessment of the impact of human activity and that observations alone indicated it could in fact have made the heatwave up to 100 times more likely than a century ago.

The European heatwave broke many records and caused widespread disruption across the continent. Heatwaves are dangerous events, however the most striking impact of heatwaves, increased mortality, is generally only reported later. Although this feels like an exceptional event, the researchers believe that we are very likely to see more extreme heat waves in future due to climate change.

To find out more please see the full study, which is available on the World Weather Attribution website.