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Saturday, November 5, 2011

Climate change and California wine grapes

Scientific studies have suggested we're in the beginning stages of a global warming. With all the concern over rising sea levels with potential coastal flooding, food shortages, and so on there are some people getting paid to worry about California's wine grape crops.

A study by Stanford University says up to half of the land now used for premium wine grapes could be lost as soon a 2040 if the predicted two degree temperature increase happens.

California's premium grapes are grown in coastal areas of the state.  Not necessarily on the coast, but close enough to get a cooling influence from the Pacific.  Climate, along with soils, are the two key elements to growing great wine.  So the thinking goes if we heat up it'll be too warm for grapes where they're grown currently.  Such as, Chardonnay and Pinot will no longer grow well in places like Carneros and the Russian River Valley.  And Cabernet in places like the middle of Napa Valley and in Alexander Valley.
Morning fog in the vineyards
Well, I ain't no scientist, but I'm not convinced these areas under a cool coastal influence will actually get warmer.  

The global weather is driven by the difference in temperatures in different regions of the land and on the water.  The coastal areas of California have a climate dependent on hot weather in the central part of the state.  As the Central Valley heats up in the summer with temperatures often hovering around 100 degrees this hot air naturally rises.  Cooler, denser air from the ocean is pulled in to replace it.  Or what's known locally as our morning fog.

Fog hugging the California coastline in summer
Image from ucsb.edu

This cooler air coming in off the Pacific is the defining characteristic of the growing season climate in California's premium grape region.

So the question is, will the coastal areas heat up equally with the interior or will this rising hot air / cool ocean air engine actually be stronger?  These global warming studies seem to take a macro view in that everywhere will heat up more-or-less equally.  Wouldn't it be interesting if the coastal areas get cooler as more ocean air is being drawn in because the central part of the state is heating up?