Higher temperatures mean that grapes in Bordeaux may ripen earlier and become vulnerable to malnutrition.
Climate change is prompting grapes in Bordeaux to ripen earlier.
The grapes also lack water during critical stages, due to drought.
The result it that aromas could lose their freshness.
Bordeaux's fabled wine grapes are under threat from global warming, climate experts told a meeting of industry leaders Tuesday.
"The pessimistic scenario shows that Bordeaux's climate, by 2050, will no longer favor Cabernet and Merlot," the backbone varietals of the region's red wines, said Jean-Pascal Goutouly, a researcher at the National Institute for Agricultural research (INRA).
"We are currently on the most pessimistic curve -- that's the emergency," he told winemakers from some of the region's most prestigious chateaux.
For Bordeaux, climate change means higher minimal temperatures and drought during the summer, the conference heard.
The first means that grapes ripen earlier, and the second that vines are more likely to lack water at a critical stage of maturation.