Researchers from three universities have found that vintages improved as temperatures rose over the past 50 years, especially in areas with cooler climates. The findings could prove troublesome for vineyards in traditionally warmer regions.

"When you talk to grape growers and winemakers today, they will still tell you climate is the final player in how good a vintage will be," said Gregory Jones, Southern Oregon University climatologist and co-author of the report. "We are going to continue to see a warming environment, and there will be some challenges the industry will have to meet one way or another."

Jones joined researchers from Utah State University and the University of Colorado to study 27 renowned wine regions in nine different countries. Using Sotheby's vintage rating system, they found that most vintages improved as vineyards' temperatures rose an average of 1.3 degrees Celsius over the past 50 years.

The effects were strongest in cool climate regions, such as the Mosel and Rhine valleys of Germany, suggesting warmer temperatures offer the greatest advantage to cold-climate grape-growing regions.

The findings will be published in a future issue of the journal Climatic Change.

A predicted rise of another 2 degrees Celsius over the next half century could have more mixed results, the study showed.

Cooler climates, such as Oregon, Washington and British Columbia, could continue to benefit from global warming.

Others argue the effects of rising temperatures on the wine industry are simply a very narrow picture of a broader problem.

"There's a heck of a lot more at stake here than wine," said K.C. Golden, policy director for the Olympia-based nonprofit Climate Solutions. "It is a sign that climate disruption is going to affect every aspect of our lives -- our ecosystems, our economies, our livelihood."

Regions with warmer climates, such as Italy's famed Chianti region, could see grapes ripen too quickly under even warmer temperatures. Grapes that ripen too quickly on the vine generally have higher sugar content, which produces more alcoholic wine with less acidity and balance.

Rising temperatures might force growers to manage vines differently to produce similar wine styles, or to plant different varieties better suited to the changing climate, Jones said.

The news could be unsettling for an industry that prides itself on regional identity and reputation.

Andrew Walker, a professor of viticulture at the University of California at Davis, agrees rising temperatures are leading to changes in the industry.

Whether those changes will be permanent remains to be seen, he said.

"I think everyone agrees in most scientific circles that change is occurring. What that change is, is still up in the air," he said. "We'll have to sort of adapt on the fly. If it really is catastrophic and not just a blip, vintners will definitely change how they plan and where they plant."

The extreme heat wave in Europe this summer, which some experts blamed on global warming, offers an example, Jones said.

"In some areas, it could have been very detrimental. Southern Italy, Greece are hard-pressed to produce any good wine this year," Jones said. "But southern England? It may be their best vintage since prior to the little Ice Age."