The vineyards and wines of France's Bordeaux region are world-famous. But unless we act swiftly to roll back our heat—trapping emissions, warming temperatures are likely to make Bordeaux's future climate less suited for producing high-quality wines—and winemakers may be forced to employ costly adaptation measures.1
For centuries, Bordeaux has been one of France's most famous wine regions.4,5 Yet if our heat-trapping emissions continue to rise, global warming may make Bordeaux's climate less favorable for high-quality wine production.6,12,13,16
Many people around the world think of France when they think of wine. Wine has enormous cultural, historic, and economic significance in that country, and is a source of national pride.
In 2008, France was the world's second-leading wine-producing nation, behind Italy.2 It also ranked second in total area devoted to vineyards, behind Spain.2 France exported more than $10 billion (€7.7 billion) worth of wine in 2009.3
Bordeaux, which produces one-third of France's quality wine, is one of the country's most famous wine regions.4 Most Bordeaux wine is red, blended from three varieties of grapes: Merlot, Cabernet Sauvignon, and Cabernet Franc.5
Winemaking is an art and a science—but climate greatly influences the quality of wine, and typically determines premium wine-growing regions around the world.6 The optimal climate for growing grapes that can be made into high-quality wine features wet, mild-to-cool winters followed by warm springs, then warm-to-hot summers with little precipitation.6
Scientists have found that changes in the climate of the Bordeaux region in the second half of the twentieth century were generally favorable for high-quality wine production.6 Decreases in precipitation when the vines were budding and the grapes were ripening (veraison)—combined with warm, dry conditions during the flowering stage (floraison)—increased the potential for sweeter, larger Merlot and Cabernet Sauvignon grapes.6 The resulting reduction in acid levels and increase in sugar-to-acid ratios improved the quality of the grapes and the likelihood of producing high-quality wine, on average.6
More recent climate and weather patterns, however, have been less advantageous for winemaking. In the summer of 2003, Europe experienced a devastating heat wave.7 Annual precipitation was as much as 12 inches (300 millimeters) below normal, leaving most of the continent in a drought.8 (See the hotspot on De Bilt, the Netherlands, for more on this record European heat wave.)
Damages to the agricultural sector were estimated at more than U.S. $16 billion (more than €13 billion), with nearly one-third of the losses occurring in France.8,9,10,11 European wine production hit a 10-year low.10
What the Future Holds
The 2003 heat wave suggests that further warming of Bordeaux's climate may not be beneficial for wine production. According to one study, an increase in the number of days above 86° F (30° C) when grapevines were flowering hastened grape ripening, and the resulting longer growing season correlated with lower productivity and lower-quality grapes.6
According to scientific projections, more frequent heat waves and even hotter summers than that in 2003 are highly likely in the coming decades.12,13 Unless we make deep and swift cuts in our heat-trapping emissions,14 summers in central Europe are expected to feel like today's southern European summers by the end of the century.15 Overall, Europe is projected to face hotter summers, less summer precipitation, and more frequent and intense droughts.16
Bordeaux's wine growers are now facing the costs of adapting to a warming climate. Possible future advances in genetics, breeding, and vineyard adaptation may help mitigate some of the adverse affects of climate change. Breeding programs may develop heat-resistant vine stocks, for example.17
Reducing our heat-trapping emissions may also help reduce the impact of global warming on winemaking in Bordeaux, and give farmers time to adapt to the region's changing climate.