A nice glass of Uh Oh

Pinot Noir makes more than a good wine. Official records have been kept on the grape harvests in Burgundy since the middle ages, and because the same type of vines have been used continuously over the last six centuries, the data from the records has provided scientists with valuable data on climate change.

"… "We were able to compute exactly the state of ripeness of the vine from the temperature," he said (Dr. Yiou, of the Laboratory for the Science of Climate and the Environment). Then, using information from church and municipal archives, they compiled a record of harvest dates since 1370.

From that data they could estimate the date of veraison, when the grapes begin to ripen and turn from green to black. This, Dr. Yiou said, is about 23 days before the decreed harvest date. "Then from the model of grape growth, we can estimate the temperature of the warm season," he added.

The researchers found a few periods of high temperatures. The 1380’s were warm – about 3 degrees Fahrenheit above the norm – as were the 1420’s, the 1520’s and the half-century from the 1630’s to the 1680’s. But after that temperatures turned cooler, with a few brief exceptions, until the past 30 years, when things really began to warm up.

"The late 20th century is exceptional," Dr. Yiou said. While this is only a local trend for eastern France, it is comparable to findings from global studies. "The trend is quite stable and unprecedented," he said.