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Record-breaking July 2019 heatwave would have been extremely unlikely without human-induced climate change in many parts of continental Europe, shows a near real-time analysis from World Weather Attribution and partners including Oxford’s Environmental Change Institute (ECI).
Over two to four days at the end of July 2019, Western Europe saw temperatures reach 42.6 degrees in Paris, while the UK set a new daily temperature record at 38.7 degrees. The effects of these extreme temperatures are far-reaching: from delayed trains and sleepless nights, to deaths from drowning and an increased mortality risk for the elderly, babies and vulnerable populations.
An international team of scientists, including researchers from the ECI, the Dutch Met office (KNMI), the UK Met Office and Météo France, conducted a rapid analysis to determine whether and to what extent the probability of these heatwave events had changed as a result of climate change. The analysis was led by World Weather Attribution, an international effort to analyse the possible influence of climate change on extreme weather events such as heatwaves, cold spells, and droughts.
Combining established modelling methodologies and observational data, the researchers found that in France and the Netherlands, the heatwave was made about one hundred times (and at least 10 times) more likely due to climate change. This means that before global warming a similar heatwave would have been extremely improbable, with a chance of happening only once in a thousand years.
In Germany the heatwave was made around 50 times more likely due to climate change (and at least 8 times more likely), and in the U.K. – where extreme temperatures only lasted 1-2 days – the heatwave was made at least twice as likely.
In all regions the researchers found that without climate change, heatwave temperatures would have been 1.5 to 3 degrees lower.
Dr Friederike Otto, acting director of the Environmental Change Institute, said: 'Every European heatwave we and others have analysed was found to be made much more likely and more intense due to human-induced climate change so it was not surprising that climate change played a role.'
She added, 'But how much more likely the heatwave is depends very strongly on the event definition: location, season, intensity and duration. This July 2019 heatwave was so extreme over continental Western Europe that the observed magnitudes would have been extremely unlikely without climate change.'
Dr Karsten Haustein, a researcher in Dr Otto’s team said, 'Heat waves are dangerous, in particular for older people prone to suffering from heatstroke and other related problems. Mortality increases with hot nights and days. Effective heat action plans can help to mitigate risks but we need to think beyond that. Trees and white roofs are a fairly simple solution. Better insulated houses and in general more investments to safeguard infrastructure that is bound to fail at high temperatures are also critical.'
Read the full report 'Human contribution to the record-breaking July 2019 heat wave in Western Europe'.