Climate Change Made Europe's Heatwave At Least Five Times More Likely
2 July 2019
By Adam Vaughan
Climate change made last week’s deadly heatwave in Europe at least five times more likely, according to a rapid analysis.
The team of European researchers who conducted the work also found humanity’s warming of the planet made the heatwave about 4°C hotter than it would otherwise have been. The findings came as new data showed that the average European temperature last month was the hottest ever for June.
The intense heatwave affected large areas of Europe, setting temperature records in Germany, Austria, Spain, the Czech Republic, Switzerland and the Netherlands. France saw the hottest temperatures, including an all-time high of 45.9°C near the city of Nîmes, a level more typical of Death Valley, California. Manure self-ignited in Spain, causing a wildfire.
Hoping to avoid a repeat of the 2003 heatwave which killed more than 70,000, authorities in France postponed exams and set up ‘cool rooms’ for people, while Germany imposed motorway speed restrictions over fears of roads cracking. At least seven deaths have been linked to the heatwave; the true toll will not become clear until much later.
Read more: Weather forecasts could soon pin extreme events on climate change
But we now know the exceptional heatwave was made much more likely by global warming, due to an assessment published on Tuesday by the World Weather Attribution group.
They used computer models to calculate the temperatures we would expect to see in France with the 1°C of warming – our current level above pre-industrial temperatures – and also without it.
They then looked at the average temperature in three days in June across France and in the French city of Toulouse and compare the observations with the models.
The results for France as a whole showed that climate change increased the probability of the heatwave by at least a factor five. The results were similar for Toulouse.
While the researchers were very confident in the heatwave being made at least five times more likely, they said the real world temperature data shows the probability could have been increased by as much as 100 times.
Geert Jan van Oldenborgh of the Royal Netherlands Meteorological Institute says although five times is the minimum, the true figure “could be much higher.” Up to 100 times is a possibility but should not be taken too seriously, the team says, because of the difficult of modelling clouds, the interaction between atmosphere and soil, and reproducing such extreme, record-breaking temperatures in models.
Compared to a heatwave in June in 1901, last week’s one was about 4°C hotter. “This is a strong reminder again, that climate change is happening here and now,” said Friederike Otto of the University of Oxford.
More on these topics: climate change