Mediterranean episodes, heat wave… What awaits Occitania with global warming

Although global warming will affect all regions of the world, it will not do so in the same way everywhere. This is the case globally, but it also applies to France, as French departments will sometimes face slightly different fates than their neighbours.

But what exactly will happen to the Occitania departments? How will global warming affect them? And will they be more than others? We take part.

Also read: Heat waves, fires… What awaits France in 2050 with global warming

Average temperature: 1.6 to 2°C increase

The average temperature recorded in Occitania in the middle of the 21st century will be 1.6-2°C higher than that recorded there in 1976-2005.

This increase will be much higher than that recorded in New Aquitaine, but the Paca region, on the other hand, will experience a greater increase in temperature.

Also read: Heat waves, fires… What awaits the Pays de la Loire with global warming

At the regional scale, the most significant increases will be observed in the departments of the East and some mountainous sectors, especially in some valleys of the Eastern Pyrenees-Orientales, an increase of 2°C.

For example, between 2040 and 2070, Albi will have the temperature level currently observed in Toulon, while Perpignan will have that of Barcelona.

Heat waves: up to 45 days in some areas

Symptoms of this increased heat include more frequent and intense hot flashes.

The number of days the region will experience this type of episode, characterized by temperatures well above normal for several days, will increase at times dramatically across the region.

Also read: Temperatures, drought… What awaits Hauts-de-France with global warming

In Loser, part of Aveyron and the Pyrenees, the number of these days under heat waves will increase by more than 30 days compared to 1976-2005, and sometimes reach 45 days, a month and a half.

The increase in other sectors is more modest (about twenty days on average, less on the coast), but will still bring the total number of heat wave days in the region to a level unmatched in France in recent years. climate.

Cold waves: fewer and fewer episodes

Warming of the Occitan climate will also reduce the number of cold spells, during which the minimum temperature is 5°C below normal for several days.

In 2050, the number of days that the region will live under this regime will decrease by only two times for the years 1976-2005.

Also read: More heat waves and fires: what awaits Corsica with global warming

For example, in some sectors in the north of the region, it will decrease from seven to three, and in some areas of the Pyrenees foothills, from three… to zero. The number of frosty days should also decrease dramatically.

Precipitation: more intense Mediterranean episodes

The region will be particularly affected by the intensification of Mediterranean episodes.

As Météo France notes in an article dedicated to these events, they have already intensified in the recent past. And it should continue to do so in the future. “Intensification of extreme precipitation in the French Mediterranean region should be a few percent of daily accumulations due to warming”, Météo France shows. In other words, the warmer the weather, the greater the accumulation of rainfall during Mediterranean episodes.

If they will gain intensity, it is not certain that these events will happen more often in the future.

Also read: Temperatures, rains… What awaits Burgundy-Franche-Comte with global warming

In general, in the median scenario, total annual precipitation is expected to decrease slightly in the east of the region and in the mountains (from 600 to 1500 mm per year to 10 to 60 mm less).

On the other hand, they are slightly higher in the rest of Occitania (an additional 10 to 30 mm for current accumulations of 700 to 1000 mm). However, Météo France says its forecasts in this area are subject to strong uncertainties.

Drought: towards drier soils

This hot weather will cause the soils of the region to dry out.

Thus, in 2050, the soil moisture index is decreasing in the entire region. However, it should be noted that such soil degradation will be less significant in the south of Gard and east of Hérault than in the rest of the region and the rest of France.

Also read: Heat waves, rain… What awaits the Grand Est region with global warming

Météo France also indicates that meteorological dry periods (days without rain) will be several days longer in the region in the future.

Fires: greater risk

The Occitanie region, which is already particularly affected by these disasters, will see the risk of forest fires become even more significant in the future.

Data from Météo France shows the number of days the “weather forest” index (which measures the risk of fires starting and spreading) will be above 40 “serious”) will increase from 5 to 45 days depending on the sector.

Also read: Fires, high heat… What awaits Center-Val de Loire with global warming

The departments that will be most affected by this increased risk of wildfires are Gard, Hérault, Aude, part of the Pyrénées-Orientales (at 30-45 days extra risk) and, to a lesser extent, Tarn, Aveyron, Haute-Garonne, or Lozer (10-15 extra days ).

This increase in the number of days at risk will lead to it being significant for at least 80 days over a large part of the Mediterranean coast.

Snow cover: More noticeable fall from the Alps

Global warming will cause a decrease in the amount of snow cover in all massifs of the region, as well as the duration of snow storage.

Thus, the number of days with 50 cm of snow at an altitude of 1800 m in Haute-Bigorre will increase from 84 in the current climate to 53 in 2050. In Upper Ariej, this total will increase from 103. to 57

Also read: Heat waves, fires… What awaits Ile-de-France with global warming

This decrease in snow cover at 1800 m is greater than would be observed in the Alps, which already benefit from more snow days, especially in the Northern Alps.

Rising waters: increased risk of drowning around lakes and ponds

As shown by maps from the Bureau of Geological and Mine Surveys, sea-level rise due to global warming will increase the risk of marine flooding during high tides in some low-lying sectors.

Also read: Heat waves, fires… What awaits Britain with global warming

In Occitania, above all, the marshy surroundings of large ponds or lakes are concerned about this potential risk.

Areas where the risk of sea flooding increases if the sea level rises by 50 cm. | BRGM

Methodology

Western France As part of the Drias* project, it studied the regionalized climate scenarios established by Météo France and deduced from them how the region’s climate would develop between 1976 and 2005 and between 2040 and 2070.

The scenario on which these projections are based is that the level of greenhouse gas emissions will stabilize only in the middle of the century and then decline slightly. Therefore, this is an intermediate scenario, implying that certain scenarios will lead to more significant changes than those mentioned above.

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