SEQUIM, Wash. -- Tom Miller rolls his metal stool down the row inch by inch, his long, leathery fingers pushing through the vines to clip grapes off by the bunch.
It's an early autumn morning at the top of the Olympic Peninsula, and Miller is doing something climate scientists believe would have been difficult, if not impossible, 50 years ago: harvesting grapes to make wine that people actually want to buy.
No matter whether they realize it, researchers say, Miller and a small explosion of new Western Washington wine-grape growers appear to be capitalizing on small climate shifts that are reshaping the global wine-growing map.
As climate changes threaten to wreak havoc on some of the world's most-famous wine regions -- France's Burgundy, Australia, parts of California -- experts say the cool-climate Puget Sound region might shape up to be one of the few beneficiaries.
"In the 1970s, the Willamette Valley (in Oregon) was at the cool-climate fringe for wine; it was one of the coolest places you could go and reliably ripen the fruit," said Gregory V. Jones, a climate scientist and wine expert at Southern Oregon University. But as temperatures warm in northern latitudes, "today Puget Sound is becoming that place."
Certainly technology and a growing thirst for boutique wines have helped drive where and how grapes are grown. But experts say it's increasingly possible to track the subtle ways climate change is altering landscapes by looking to vineyards around the globe.
Hotter ripening periods over the past 30 years have increased the alcohol content of rieslings in Germany's Rhine River Valley. In Napa and Sonoma, Calif., earlier springs and fewer frosts have helped boost wine quality.
Australian vineyards have extended droughts, and other European growers are facing never-before-seen bug infestations. Vineyards are even cropping up in places such as southern England where they haven't been seen since before the Little Ice Age and the reign of Henry the VIII five centuries ago.
And some, like Miller's Dungeness Bay Vineyard, now are appearing where they haven't been seen at all.
Using clippers and wearing gloves so they don't accidentally snip off their fingertips, Miller and a group of friends fill a half-dozen plastic buckets full of a white-wine grape called siegerrebe. It's just one of several varieties that spill from tight, neat rows in his backyard.
Miller and his wife bought their Sequim property in 1995, and Miller a veterinarian and horticulturist had been using the ground to grow kale and oats to feed sheep. After stopping to visit one of the Puget Sound's first vineyards at the Bainbridge Island Winery in 2000, he thought: Why not? He had grown wine grapes before and knew enough to experiment.
"I couldn't think of a good reason not to try it," Miller said in his Scottish brogue.
He is hardly alone. Just a mile down the hill, another neighbor has started a vineyard, and a former stone carver from Italy has planted several thousand vines outside Port Angeles. In fact, while Western Washington, like Vancouver Island, has had a handful of wineries since the 1970s, the real growth has come only in the past decade.
"In 2000, I could count the number of people growing wine grapes in Western Washington on two hands," said Gary Moulton, a horticulturist with Washington State University's research and extension center in Mount Vernon. "Now there are about 75 growing grapes commercially and another 40 or so amateurs."
The scale remains quite small given Western Washington's vastness, but like the entrepreneurs who rolled into Oregon decades ago with dreams of producing the next great red, Western Washington's newest winegrowers are pioneers.
It's unlikely even this boom could have been possible half a century ago. Unlike the Yakima or Okanogan valleys, Western Washington doesn't get or stay hot enough to produce Cabernets or good table grapes. But growing seasons between the last spring frost and the first fall freeze have lengthened up and down the West Coast since the 1950s, making it increasingly possible to consistently grow cool-weather crops, including grapes like siegerrebe, Madeleine Angevine and pinot noir.
The same pattern of early bud-breaks and bloom that's sparking a Washington revolution also is creating unease to the south.
"The best flavor in a grape arrives at a particular moment -- when it ripens, but just barely," said Chris Howell with Cain Vineyard in California's Napa Valley. "You don't want them hanging out there too long and never getting ripe. But you also don't want them to get ripe" too soon.
Top vineyards are so susceptible to minute changes in weather that even slight climate variations can make the difference between a lackluster and high-quality grape. While heat can alter the balance of sugar and acid that gives wine flavor, some of that can be adjusted by winemakers.
But Kimberly Nicholas Cahill, a scientist at the University of California, Davis, recently learned that even slight increases in temperature and light concentrations also can change elements of a grape that give wine its color and aroma, which in turn affects taste and quality.
And one of the most finicky grapes is the popular -- and profitable -- pinot noir, which can only be grown to high quality within a 4-degree range of average growing-season temperatures. Generally speaking, the pinot noir region of California's Napa Valley is already at the upper limit for those temperatures, while some parts of the Puget Sound region are near the lowest.
With climate change slowly pushing the thermometer up, what does that mean for Napa Valley's multimillion-dollar pinot noir crop?
"That, of course, is the $64,000 question," said Dan Cayan, a scientist with UC-Davis' climate-research division.
It's possible the cool, moist air coming off the Pacific could moderate rising temperature's impacts on the valley. But nobody really knows for sure.
"For us, it's really too soon to say," said Napa Valley grower Dave Graves, with Saintsbury Vineyard. "Nobody's pulling up stakes and moving out."
What's clearer is that growers in places such as Puget Sound increasingly seem able to produce nice wines from cooler-weather grapes, such as pinot noir, although they sometimes still need a little help.
Miller recently ripped out one row of vines after it produced a beverage he charitably dubbed "Brussels-sprout water." And to make sure his pinot noirs ripen appropriately, he still wraps the plants in plastic to form a mini-greenhouse.
But on this autumn day, the siegerrebe tasted sweet and had its perfect yellow-purple hue, so Miller ferried the grapes by tractor to a garage, where his crew took turns crushing them in an Italian-made hand-crank oak barrel. They will be used to make a low-alcohol wine that should be ready to drink by next spring.
By then, Miller will be watching the ground for the season's last frost so he can start growing again.