In France's storied Bordeaux wine region, an experiment aimed at helping some of the world's best-loved tipples to weather the ravages of climate change is starting to bear fruit.
On a small estate in the southwestern region where Merlot and Cabernet Sauvignon have reigned supreme for decades, several non-indigenous grape varieties nurtured by researchers over the past 10 years have taken root.
The idea of growing Portugal's Touriga Nacional or Georgia's Saperavi in Bordeaux would have seemed heretical to the purists behind France's strict wine appellations just a few years ago.
But with experts warning that the region that gave the world Chateau Margaux could be one of the worst hit by the climate emergency, the race to find grape varieties that can withstand extreme heat has intensified.
"In 2050, Bordeaux's climate could be like that of Seville," Bernard Farges, president of the Bordeaux Wine Council, told AFP, referring to the Spanish city more than 1,000 kilometres (600 miles) to the south.
"If we don't do something about grape varieties now, we risk losing what makes our wines unique," he said.
A study published in the American Proceedings of the National Academy of Sciences in 2013 caused shock with a warning that climate change might wipe out up to 86 percent of wine production in Bordeaux, as well as in the Rhone Valley, in four decades.
- Early harvests -
Five years later, France took a radical step: it relaxed the rules governing which grapes can be used for which wines in a given region, allowing for experiments with new varieties that are more resistant to extreme weather conditions.
Bordeaux was one of the first regions to seize the opportunity by allowing producers to use some of the hardier new grapes in their blends starting with the 2021 vintage.
The southern Languedoc and central Beaujolais regions are also experimenting with new varieties, and producers in the northern Champagne region, which is increasingly prone to devastating late-spring frosts, are looking at following suit.
With temperatures in southern France regularly hitting 40 degrees Celsius (104 Fahrenheit) in summer, the issue has gained increased urgency.
Harvests have been scheduled up to a month earlier than the longstanding early September norm, and the resulting wines lack the acidity needed for balance.
"Thirty years ago, the wines were coming out with an alcohol content of 11-11.5 percent, whereas today it's more like 13.5-14 percent," said Agnes Destrac-Irvine, an agronomist at France's National Research Institute for Agriculture, Food and Environment (INRAE).
The merlot grapes that account for 65 percent of the vines planted in Bordeaux are particularly susceptible to rising temperatures.
- Taller vines -
Destrac-Irvine is one of the leaders of a decade-long experiment being conducted by INRAE and other partners close to Bordeaux with grape varieties selected from around Europe.
From an initial sample of 52, six have been selected for experimental use in small quantities for Bordeaux and Bordeaux Superieur wines over the next 10 years, including Portugal's late-maturing Touriga Nacional and Alvarinho varieties as well as the Marselan grapes native to the Languedoc region.
Vineyards in Beaujolais, famous for the vin nouveau released to great fanfare every November, are also introducing more heat-resistant varieties, like Syrah and Viognier, usually found further south in the Rhone Valley.
"In the next 10 years, due to global warming, the varieties best suited to the south (of France) will also be the best suited to the north," Pierre-Olivier Sauvaire, manager of the Chateau de Varennes estate in Beaujolais, predicted.
Other practices being tested in Beaujolais include planting taller vines with reduced leaf canopy to reduce photosynthesis and delay grapes maturing and covering the vines with anti-hail nets that also provide shade from the sun.
For Sylvain Paturaux, a producer of Beaujolais Fleurie wines, the challenge is also to find more environmentally friendly vines that require less fungicide to fight the mildew that regularly afflicts French harvests after heavy summer rains.
"Wine-making is a long-term business. We're planting now for the next 30 years," he said.