Wine and climate change

By Leigh Pomeroy

Also published in the September 2019 issue of Mankato Magazine.

Those who know me know about my interest in — actually, concern about — climate change.
Human civilization, which has only developed over the last 12,000 years, has had a huge impact on the land and waters. Now we know that civilization has also changed the delicate chemical balance of the atmosphere and the oceans — so much so that a growing number of scientists are saying that unless we act quickly, our very civilization is in danger of collapsing.

In other words, should a cataclysm arrive as a result of climate change, humans will survive, but civilization as we know it will not. Which means bye-bye $200-per-bottle Napa Valley Cabernet Sauvignon, lavish cruises to the Caribbean and even your gas-guzzling SUV.

Wine is hardly necessary for human survival, although some people may think so. (And yes, I’ve been accused of such a belief.) While in some cultures it’s part of the meal, it is for the most part an add-on, a luxury or at least a lubricant for the human social experience.

That said, how in fact is the warming and changing climate affecting the growing and production of wine?

I have certainly seen this from personal experience. When I started in the wine business in 1972, it was nearly unthinkable to grow grapes in Oregon’s northern Willamette Valley and in the hills west of Portland. “Too cold,” the experts said. “Too rainy.” Yet today there are almost 300 wineries in this area alone. And in some years now the vintners complain that the weather is too hot.

Also in the early 1970s, only a few vineyards existed in the cool Carneros region abutting San Francisco Bay in southern Napa and Sonoma Counties. The thought was that the land was only useful for grazing cows. Today the area is wall-to-wall grapes interspersed with dozens of wineries.

Ditto with the newer Sonoma Coast AVA. Like the Willamette Valley and Carneros, much of that area had been considered too cool for grape growing. Not anymore.

Admittedly, much of this expansion has been fueled by America’s passion for varietal and sparkling wines made from pinot noir and chardonnay, both cool-climate grapes. Still, those areas have grown noticeably warmer.

Europe has seen similar changes. Where once red wine from the warm Rhône Valley was trucked north to augment weaker Burgundy in off years, today the pinot noir of Burgundy is able to stand on its own, unless there is a rain deluge in September.

Prior to the 1970s, Bordeaux on average would have in a decade two catastrophic years and two great years with six of varying quality. But today we see good-to-great years (quality-wise) almost every year, including every vintage since 2008, except for perhaps 2011, 2012 and 2013, all of which, according to wine guru Robert Parker, are only “above average” (like Lake Wobegon children, according to Garrison Keillor).

Alcohol levels are also rising because of the warming climate. Except in extraordinary years, Bordeaux used to be 12-13%; now it’s a full percent higher. Napa Valley Cabernet used to be 13-14%. Now I see them in the 14-15% range, some even 16%. California Chardonnays, once in the 12-13% range, now regularly list at 14%. And I’ve seen Châteauneuf-du-Papes from the amazing 2016 vintage in the 16% range as well. Yikes!

On top of all this, harvests have begun earlier. In Napa Valley, for instance, grape picking used to start at the beginning of September. Now the harvest begins halfway through August, with some grapes for sparkling wines picked as early as late July.

Yet the changing climate does not just mean warmer weather. It can also mean more freakish weather, like unexpected hail storms and rain events that can damage vineyards during flowering and harvest times.

But in the future it might also mean colder weather. Yes, you heard me right. The reason why Europe can grow cold sensitive Vitis vinifera grapes that Minnesota cannot, even though Minneapolis and Bordeaux are the same latitude, is because of the warm North Atlantic Current, an extension of the Gulf Stream. Scientists have been predicting for some time that the freshwater melt from Greenland will slow down and even reverse that current, throwing Europe into a much colder climate pattern.

So, it is possible that one day in the not-too-distant future, a warmer Minnesota will be able to grow prized vinifera grapes while Europe, in order to save its wine industry, may have to turn to the cold-tolerant French-American hybrids that Minnesota now grows.

Cabernet Sauvignon from Minnesota? I wouldn’t bet against it.