DITCHLING, England -- While British climate scientists are dueling with skeptics over evidence of global warming, winemakers here have been sampling some evidence of their own. Much of it tastes like champagne, and it seems to be rapidly improving.
This century could see a river of new English wine if climate scientists are right in their predictions of rising global temperatures, with vines being grown possibly as far north as Scotland, and with the south of England possibly even becoming too hot, according to geologist and wine expert Richard Selley.
"If the predictions are correct, then there will be a heyday for English wine in southern England over the next 20 years or so. But then it will move steadily north," he told E&E.
Already, the effects are being seen in vineyards across Kent, Sussex and Surrey, the warmer counties of southeastern England, with growers reporting earlier and earlier harvests and rising sugar content in the grapes -- a crucial ingredient for creating alcohol.
"We have only been here since 1994. But even since then, the picking dates have moved back. We now harvest in the very first week in October. I am told that 20 years ago, it was always in the last week," said Michael Roberts, owner of RidgeView Wine Estate, about 50 miles south of London.
Roberts specializes in sparkling wines, growing only the three champagne grape varieties, chardonnay, pinot noir and pinot meunier, using the in-bottle secondary fermentation method supposedly invented in the Champagne region of France but actually first mentioned by British physician Christopher Merret in 1662 in a paper describing English wines.
"I expect that over the next 20 years, we will be able to start picking in late September," he added after a tour of his winery, which is already taking on, and sometimes beating, top competition from across the world and even from Champagne itself.
Warmer grapes mean no more giving wine away
"The beauty of that is that we are able to pick the grapes when they are fully ripe. In Champagne, they are having to pick them before they are fully ripe because it is starting to get too hot for the grapes, so we already have an advantage," he added.
Roberts, whose vineyard is only 20 acres but who also processes the grapes from a total of 170 acres of vines, is by no means alone in his experience of the effects of climate change on the vines and wines.
Slightly closer to London is the giant Denbies Wine Estate, one of the largest single vineyards in northern Europe, with 265 acres of vines. There, harvesting has moved back by at least two weeks in the past 20 years, the ripening window has gotten longer, and the risk of early frost that can kill the buds and threaten the crop has gone down, said Chris White, Denbies' general manager.
"We have clearly experienced change, not just in what we can grow but the quality of the grapes and the size of the yields," he said. "Two decades ago, we nearly had to give the wine away. Now, our biggest single problem is keeping up with demand."
"People are starting to insist on having English wine. Supermarkets and restaurants are clamoring for it. More vineyards are coming, and others are expanding," he added.
It is by no means the first time that wine growing has come to Britain. Selley has traced four distinct periods, starting with the Romans -- one of whose vineyards was right next to the present location of Denbies -- then retreating before returning twice in warm periods in the 11th and 14th centuries.
Ebbs and flows correlate to climate
Each time, the vines have ebbed and flowed in direct correlation to changes in the climate, he said. The current phase is simply the fourth and latest.
"Wine growing in Britain has always coincided with blips in the climate," he said, stressing that he is not a climate scientist but rather a petroleum geologist with a strong interest in the geology and history of wine growing.
But based on scientific estimates that warming from carbon emissions due to burning fossil fuels for power and transport could raise global average temperatures by up to 4 degrees Celsius this century, Selley has also gone into the wine prediction business.
He suggests that by 2050, wine growing could be commercially viable in England up to a line drawn across the country north of Wales, and by 2100, it could even extend right up to the border with Scotland.
"Some 50 or so years ago, England was limited to growing colder-climate German grape varieties, and only in the south. Now, warmer-climate varieties are being introduced. If the climate warms as predicted, even warmer climate varieties will come in the south, and the others will move north," he said. "It might even eventually get too hot, except for table grapes in the south."
English wine production has indeed been growing rapidly, albeit from very low levels. There are now 416 vineyards, with a total of 2,732 acres under vines, and 116 wineries in the country producing an average total of 2 million bottles a year. Latest estimates suggest that the acreage under vines last year might have gone above 3,345 acres, representing a 50 percent rise in the past five years.
'Bring on the next 20 years'
The biggest single wine type is sparkling wine, with about 45 percent of the total, followed by still white wine, with 43 percent, and red/rose, with 12 percent, according to figures from industry group English Wine Producers.
It predicts that the sparkling sector will cement its dominance in coming years because most of the new plantings are in that field, with the three champagne grape varieties grown at RidgeView accounting for 40 percent of total varietal plantings.
"The U.K. is the biggest market for champagne after France. Germany and the United States together still don't equal U.K. imports," said Roberts. "We have proved that we can make wine as good as Champagne."
"And if Richard Selley is right, then bring on the next 20 years. People have always drunk wine, and will continue to do so. It is just that in future, it will be English wine," he said.
But while English wine may be anticipating a sparkling future as climate change progresses, over in Devon, on Mark Diacono's Otter Farm, described as the only climate change farm in the country, a bold experiment in 2006 to plant an olive grove of 120 trees to make English olive oil has met with mixed results.
"The olives are peculiar," he said in an e-mail response to a question on progress to date. "Some have died, some doing ok, some pretty well, all down to which variety. I've recently got another few hundred of a new Spanish variety that seems to be doing very well in colder areas in Spain and I'm optimistic that they will produce well here in good summers."
"First harvest is impossible to say," he said. "It could be this year if the summer is a good one, or five years away."