Human contribution to the record-breaking June 2019 heat wave in France
Contribution des activités humaines à la vague de chaleur record de juin 2019 en France
Van Oldenborgh, Geert Jan ; Philip, Sjoukje ; Kew, Sarah ; Vautard, Robert ; Boucher, Olivier ; Otto, Friederike ; Haustein, Karsten ; Soubeyroux, Jean-Michel ; Ribes, Aurélien ; Robin, Yoann ; Seneviratne, Sonia I. ; Vogel, Martha M. ; Stott, Peter ; Van Aalst, Maarten
● Every heat wave occuring in Europe today is made more likely and more intense by human-induced climate change. How much more depends very strongly on the event definition: location, season, intensity and duration. ● We use an event definition that focuses on health impacts, the three-day average of daily mean temperature. We considered two spatial scales: the whole of France and one city, Toulouse. We only consider June heat waves because they have a different impact and different trend from heat waves in July and August. ● The observations show a very large increase in the temperature of these heat waves. Currently such an event is estimated to occur with a return period of 30 years, but similarly frequent heat waves would have likely been about 4 ºC cooler a century ago. ● Climate models have systematic biases in representing heat waves at these scales and show smaller trends, more year-on-year variation and fewer really severe heat waves than the observations. ● Combining models and observations we conclude that the heat wave was made at least 5 times more likely. ● Heat waves are deadly, although this is not readily visible at the time. This risk is aggravated by climate change, but also by other factors such as an aging population, urbanisation, changing social structures, and levels of preparedness. The full impact is only known after a few weeks when the mortality figures have been analysed. Heat plans have reduced the impact in France and other countries, and are becoming even more important in light of the rising risks.</p>
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