Two heat waves, France on drought alert, thousands of hectares gone up in smoke and the Mediterranean overheating, etc. According to the forecasts of climate experts, and in particular those of the Intergovernmental Panel on Climate Change (IPCC), these episodes symptoms of climate change will intensify and become more recurrent. The summer of 2022 is only halfway there and France is already experiencing one of its worst summer periods.
But to know if this season will indeed be the worst experienced in our modern era, “we will however have to wait until the end of the summer to be categorical”, answers Jean Jouzel, climatologist, former vice-president of the scientific council of the IPCC and co-author of Climate: let’s talk about the truth (Ed. The Peregrines).
Intense fires in series
However, it is already possible to say that the events that follow one another are particularly extreme this year, in terms of their duration on the one hand, and the extent of the territories affected. Gigantic fires have already marked France in the past. But the pace got carried away this summer, with 1,800 hectares burned at the end of June in a military camp in the Var, 1,250 in the Pyrénées-Orientales, 650 in the Cévennes in early July, 1,600 south of Avignon, 300 in Brittany and even 21,000 in Gironde, etc.
What if some of those forest fires were started by a criminal act and 90% of fire starts are triggered by human activity, their intensity, particularly in Gironde, is due to the strength of the wind and the high temperatures. In the South-West, these fires also began to be brought under control from the end of the heatwave episode on July 19.
A particularly hot summer…
This episode of very hot weather was the second of the summer, when we were only in mid-July. “We had two heat waves, a very hot summer, especially very dry. We can always have a less bad month of August, but we must remember that in 2003, the two weeks of heat wave occurred at the beginning of August,” reminds 20 minutes Jean Jouzel.
The weather forecast is also in the direction of a new episode. From Sunday, a new heat wave will affect France according to Météo-France. It should last less time and will probably be less intense. But summer does not end until September 21, and according to Jean Jouzel, France is not immune to a new wave of very high temperatures. “What we have already experienced is still extremely marked, even if the record for the heat wave in the summer of 2019, 46°C in the Hérault, was not reached there. it’s the duration of the episode that calls out”, comments the climatologist pointing out the fact that this year, even Brittany was not spared.
…and dry
These long-lasting heat waves are accompanied this year by an unprecedented drought since 1959. Currently, 93 out of 96 French departments are subject to water restrictions. In Haute-Savoie, for example, eight of the department’s nine catchment areas have been on heightened drought alert since July 19. The weakness of the water resource is due to “a history of low rainfall during the fall, further upstream in the year”, according to the secretary general of the prefecture Thomas Fauconnier.
Indeed, according to Jean Jouzel, the rainfall for the month of July 2022 is equivalent to “15% of a normal month of July” and “if it lasts even two weeks in August, it would become a critical situation in many sectors, such as agriculture, energy production and even tourism would be affected”, lists the climatologist.
Risks of flooding to be expected
In addition to the consequences of this very dry summer, there is the risk of flooding. With warming temperatures, evaporation is more intense and the soil becomes very dry. And as very hot periods can often end with torrential rains, the risk of flooding, although difficult to predict, cannot be ruled out, especially in the north of the country. “These dry soils will absorb less rain” and could therefore favor deluges, as experienced in Germany and Belgium last year, recalls our expert.
In the South, another lever could also increase the risk of heavy precipitation. The Mediterranean has been affected by a major marine heat wave since the end of May, posting a temperature 6°C above average. “As the sea is very hot, it will cool more slowly, which increases the risk of torrential rains due to a Mediterranean episode”, warns Jean Jouzel again. This meteorological phenomenon is indeed defined by Meteo France as “intense precipitation over the Mediterranean regions”, specifying that “the equivalent of several months of precipitation then falls in just a few hours or a few days. »
Summers from bad to worse
So should we expect catastrophic summers every year? “Not every year, reassures Jean Jouzel. But more and more often. “It is possible that next year we will have a more normal summer, whereas last year we had a rotten summer, he slices. Nevertheless, these consequences of global warming “no longer surprise us, they have been announced for thirty years and they will accelerate with the rise in the temperature of the planet”, he admits.
According to the forecasts of the latest IPCC report, these extreme climatic episodes will be more and more frequent and more and more intense. “Before this type of event occurred every ten years, currently, we have doubled this frequency. With only an additional 1°C for the planet, it must be multiplied by four. If we reach 4°C more, these episodes will be almost annual,” predicts the climatologist.
However, Jean Jouzel hopes that these effects of climate change now clearly visible in France will contribute “to raising awareness of the reality of global warming, of the fragility of our environment and that this will lead citizens to pay more attention to their shares”.