Feel the heat: global warming is re-shaping the wine world by degree.

Most would agree that global warming is bad for mankind; at minimum, altered weather patterns play havoc with agriculture. And among most of the world's long-time winemakers, it is accepted that the relatively predictable pattern of annual average temperatures in the primary production regions has changed. The past 10 vintages in Germany are warmer than in any decade on record, for example. For those questioning how long such records have been kept: Germany's detailed vintage descriptions go back to the mid-1300s.

But, as may delight some global warming nay-sayers, previously cool vineyard regions such as Germany are finding that climate change can offer good news. Where once only two or three German vintages each decade saw ripe grapes, now nearly every vintage in the last decades has been riper than in all but the most unusual of recent years.

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Nearby northern France has seen the same trend, but while Germany's recent string of successful harvests has been the talk of the wine community, France's Loire Valley has experienced a significant a change of fortune.

Only a decade ago, Loire Valley wines were tart and racy; the consistently cool and cloudy landscape didn't create wines with the fullness and richness of, say, California. The most obvious example is Loire Valley Sauvignon Blanc. Ten years ago, most were herbal and lean. Since the hot vintage of 2000, every harvest has yielded unusually ripe wines.

Some traditionalists quarrel with these wines, not because they're less than tasty, but because they're different from most Loire wines of the past. While I would concur that the current crop of Loire Valley Sauvignon Blancs are far fruitier and more generous than they used to be, that doesn't make them less interesting wines. It makes them better wines.

Even chilly old England may be in for more serious viticulture as a result of global warming. A decade ago, the idea of producing quality Pinot Noir wines in Great Britain was as absurd as a Monty Python skit. Today, British producers such as top-flight sparkling winemaker Nyetimber are growing Pinot Noir. Yes, most of that Pinot Noir is intended for sparkling wines, but today there are producers there offering stand-alone Pinot Noir bottles.

THE NEW FRENCH PARADOX?

Across the Channel, higher temperatures are creating problems for Bordeaux's quality-conscious vintners. In vintages such as 2000, 2003 and 2005, higher temperatures resulted in shorter ripening cycles. While the traditional thinking has been that the hottest vintages in Bordeaux are the best ones, that attitude arose back in an era before global warming.

We are beginning to see growth cycles in Bordeaux that are closer to warm climate wine regions such as Napa Valley and the Barossa Valley in Australia. These shorter cycles result in grapes that may have sugar ripeness, but may not achieve phenolic ripeness. When grapes don't have phenolic ripeness, they usually end up having green and astringent tannins.

Vintners in California have long been adept at creating the best possible balanced wines from grapes that have green and gritty tannins. In Bordeaux, these are new and unfamiliar problems, and just as the tannic (and hot) 1975 vintage of Bordeaux never really softened and never gained an ounce of charm, there is reason to predict a similarly unhappy future for much of the output from the 2000, 2003 and 2005 vintages.

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Still, many wine writers believe those uber-ripe vintages have produced great wines. Time will tell. But at this writing, Bordeaux vintners are beginning the 2007 harvest, the earliest harvest ever recorded.

Meanwhile, Mediterranean Europe is faced with decidedly higher temperatures as well. In vintages such as 2003, initially glowing remarks about wine in the Rhone have given way to more circumspect views; some of the 2003 bottlings already seem to be losing their fruit.

The most egregious effects of shifting temperature norms seems to be vine stress in places such as the southern Rhone, Tuscany and much of Spain. Irrigation can ameliorate many of the effects of hotter temperatures. Once forbidden in the European Union, irrigation is now wisely allowed in many areas.

In sunny California and Australia's historically sun-burned vineyards, alcohol levels also have been going up for years. Countless explanations are offered, but it's hard not to conclude that rising temperatures result in higher sugars in the grapes, and that eventually means higher alcohol levels. Like many aspects of global warming, it's impossible to prove to the skeptics that climate change is the cause.

But winemakers don't deal in certainties. They deal in the vicissitudes of vintages, pests, vine diseases, stuck fermentations and, yes, climate change. They have to make good wine regardless of nature's challenges. The smart ones will switch grapes or change techniques to keep up with changing climatic conditions.

The smart buyers will become more flexible, too. Instead of buying the same wines from the same traditional areas, sharp shoppers will look around because they know that changing climates will offer opportunity to new grapes in new regions. British Pinot Noir might not be the best bet, but just as the tried and true may no longer be as trustworthy, the traditionally less-important and cooler viticultural areas may offer both quality and value.

Doug Frost is a Kansas City-based wine and spirits writer and educator. He is one of only three people in the world who is both a Master Sommelier and Master of Wine.

BY DOUG FROST, M.S., M.W.