In April, a rare late frost hit some of France’s best-known and most prestigious wine regions, wiping out a third of French wine production worth around two billion euros in space. of a few nights.
And scientists said on Tuesday that climate change had greatly increased the chances of such an event, which Minister Julien Denormandie called “probably the biggest agricultural disaster of the start of the 21st century”.
They warned that this will increase them even more in the future.
The results come from World Weather Attribution, an international organization that analyzes the link between extreme weather events and global warming.
They examined data from an area covering vineyards in Burgundy, Champagne and the Loire Valley and performed 132 climate model simulations.
The study concluded that a warmer climate increased the likelihood of an extreme frost coinciding with a growing season by 60 percent.
# photo1 And the co-author of the study, Robert Vautard, of the Pierre-Simon Laplace Institute for Climate and Environmental Sciences, put the odds even higher than that.
In a bid to limit global warming to 2 degrees Celsius above pre-industrial levels probably out of reach, he told an online press conference that he expects “the likelihood of a such event increases by an additional 40% ”.
– ‘Existential question’ –
The plunging temperatures in April were particularly deadly as they followed a period of unusually warm weather in March which favored budding of trees and vines.
“Bud burst” – when young leaves begin to unfold to prepare for photosynthesis – makes vines vulnerable to deadly freezing temperatures.
Wine growers have always been wary of late frosts, but they are now forced to redefine what they consider “late”.
Budding “is happening earlier and earlier,” said climatologist and study co-author Nicolas Viovy, “it has increased by almost 15 days since 1980”.
To analyze the likelihood of future devastating frosts, the researchers had to take into account two consequences of warming: a decrease in freezing temperatures on the one hand and an earlier start of the growing period on the other.
# photo2 “It’s a real scientific breakthrough to be able to analyze composite events” like this one, said Samuel Morin, who heads a combined unit of CNRS and Météo France, which contributed data and researchers to the report. .
“You can’t say of an isolated weather event ‘it’s because of climate change’. But we can measure to what extent climate change has affected the likelihood of such an event happening, ”he told AFP.
The fallout from the April frost was widespread with hundreds of thousands of hectares of crops and vines in 10 of the 13 French regions affected, affecting kiwis, apricots, apples, beets and rapeseed.
Markus Reichstein of the Max Planck Institute, another co-author of the study, stressed the urgency of being able to anticipate the likelihood of such events.
“Economically, this can be quite critical,” he said at the press conference, adding that for winegrowers “it could be an existential issue”.
© 2021 AFP