Aug. 29 (UPI) -- According to a new survey of Burgundy wine grape harvests in France, picking has begun an average of 13 days earlier over the last 30 years than during the previous 650 days.
The findings, published this week in the journal Climate of the Past, support the conclusions of previous studies suggesting climate change has accelerated of the last three decades.
Researchers used modern agricultural and climate records, as well as historical records, to analyze the timing of grape harvests in Beaune, the wine capital of Burgundy, a central region of France.
"We did not anticipate that the accelerated warming trend since the mid-1980s would stand out so clearly in the series," Christian Pfister, a professor at the Oeschger Centre for Climate Change Research at the University of Bern in Switzerland, said in a news release.
By marrying historic city council records and newspaper reports with modern data, scientists were able to compile the longest continuous record of wine grape harvests.
"The record is clearly divided in two parts," said Thomas Labbé, a researcher at the universities of Burgundy and Leipzig.
Up until 1987, grapes were harvested beginning on September 28. Over the last three decades, grapes have on average been harvested beginning on September 15. Because wine grapes are especially sensitive to temperature and moisture, harvests must be properly timed.
Records showed hotter, drier summers yield early harvests, while cooler years delay harvest times.
Scientists compared their results with detailed records of temperature Paris over the past 360 years. The results were in agreement.
"The transition to a rapid global warming period after 1988 stands out very clearly. The exceptional character of the last 30 years becomes apparent to everybody," said Pfister. "We hope people start to realistically consider the climate situation in which the planet is at present."
