Fewer flakes in mid-mountain, nothing or almost nothing in the plains: “But where are the snows of yesteryear?
The refrain of François Villon is likely to resonate in the first degree in 2100, according to projections that Météo France publishes this Tuesday.
The DRIAS report on possible climate projections in mainland France updates the latest dataset, which dates back to 2014. Jean-Michel Soubeyroux, climatologist and coordinator of the report, specifies: “The new simulations are hotter than the previous ones.
There is a deviation of 0.2 to 0.3 degree.
"
Outdoor cafes in January?
Météo France shines the spotlight on the three scenarios of the Intergovernmental Panel on Climate Change (IPCC): the worst-case scenario if nothing is done;
the option in case of significant political action against greenhouse gas emissions and a middle way.
In all cases, until 2050, the warming in mainland France is more or less the same: + 2 ° C.
"Until then, history is written: the inertia of the climate system is two or three decades," explains Jean-Michel Soubeyroux.
The greenhouse gases that fuel the machine have already been emitted.
However, the situation is then very different.
After 2050, either the temperature stabilizes until the end of the century.
We will then stay warm inside, a mulled wine in hand.
Or, if we do nothing, “the thermometer will rise by 3.5 ° C on average, that's very important!
»Insists Jean-Michel Soubeyroux.
For foresters, farmers for example,
less cold
frost (
Editor's note: a cold and thick fog, which freezes when falling
) is a game-changer.
“Some seeds, like those of beeches, need cold to germinate.
Milder winters could pose problems of forest renewal, ”points out Nathalie Breda, research director at the National Institute of Agronomic Research (INRAE).
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In order not to see that the forest is half empty, "it seems that globally in forests, field crops and orchards, global warming limits fungal diseases", reminds the tree expert.
More rare colds
At the end of the century, in the “it doesn't matter, we don't change anything” scenario, Météo France estimates that frost days could become exceptional.
Good news for road safety?
Not necessarily.
“Even with a much warmer scenario, there will be occasional spikes of cold, the risk is that we will completely lose the habit, predicts Jean-Michel Soubeyroux.
A real challenge when we estimate that we have a meteorological memory of five to ten years.
The road managers will thus have to keep piles of salt.
Ditto in hospitals or in the energy sector.
The best proof of our weather amnesia?
"The few cold days, with snow in the plain a few weeks ago, created a stir but they are synonymous with a normal winter, very far from the cold waves of 1985 or 1987", remarks Jean- Michel Soubeyroux.
Simply, the last seven winters have been very mild.
There will always be ski resorts but ...
According to the report, the warming will be - and is already even - more marked in mountain areas, particularly in the Alps and Pyrenees.
In addition to the overall rise in mercury, heights are subject to the “albedo effect”.
Quèsaco?
This is the reflective power of a surface which explains why a black T-shirt is warmer than a white outfit.
Ditto for the mountain soil, dark, which will heat up all the more quickly if it is devoid of snow, white.
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"The climate is our priority subject," specifies Alexandre Maulin, president of the association Domaines skiables de France.
Below 1,500 m, the risk of a lack of snow will be more sensitive at the end of the century.
It is for this reason that we launched the general mobilization two years ago with strong commitments to decarbonize our stations.
»Hydrogen groomers and tight water management, for example.
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The question is all the more sensitive as snow culture cannot solve everything.
“To have snow, it is not enough to have a cannon, insists the boss of Météo France, Virginie Schwartz.
It needs to be cold enough for the coat to hold, you need to have water too.
"
But even in the most extreme projections, Alexandre Maulin does not believe in the end of sliding sports: “There will always be stations but we will have to deal with the variability of snow, which will be greater.
It's a formidable challenge!
"The fact remains that the" rain and snow limit continues to rise ".
From 1,200 m in the past to around 1,500 m today, it could climb to 1,700 m by 2050.