France's top vineyards receive a surprising effect from climate change: it makes French wines taste better. A new study has found that climate change makes the conditions needed to ripen fruits more frequently. This phenomenon has been historically linked to producing fine wines.

Study co-author Benjamin Cook said that before 1980, vineyards need drought to produce the heat required for early harvest. The climate change-induced heat since 1980 has produced hot summers and early harvests without the need for drought. Cook is also a climate scientist at NASA's Goddard Institute for Space Studies.

The climate change-related heat withstands even the drenching rains during summer. It's the heat that helps ripening grapes to develop tannins, sugars and acids. This means there is an increase rate for earlier harvests, which is good news for vineyards in the Burgundy and Bordeaux regions in France.

"There is a very clear signal that the earlier the harvest, the much more likely that you're going to have high-quality wines," said Cook, who worked with co-author Elizabeth M. Wolkovich from the Harvard University in the new wine study published in the Nature Climate Change journal on Monday, March 21.

In the study, the researchers analyzed over 500 years of harvest records and found that more recent vineyard harvests across France occurred two weeks earlier, on average, compared to the frequency in the past.

"One of the strengths of this paper is that it covers all of France. These records come from ... Burgundy, Bordeaux, Loire, and even from Switzerland, so we're looking at an aggregate of many data sets that are put together to get one picture of how a large region is changing," said Wolkovich.

Wolkovich added that climate is at the heart of a good quality wine and temperature is the biggest driver that signals when to harvest the wine grapes. These fruits need to be perfectly ripe for the picking, just when they had accumulated the right balance of sugar and acid. Climate change coaxes the fruits to mature faster.

Cook stressed, however, that the better wine hypothesis may only be good to a limited extent. In 2003, France had one of its earliest harvests during which farmers harvested grapes several weeks in advance during an extremely dry growing season. The wine quality was only average.

Photo : Lou Stejskal | Flickr