The Napa Valley, once again, finds itself featured in the media as the poster child for the potential results of climate change. Perhaps because wine grapes, more than any other crop, are sensitive to vintage temperatures (and climatic conditions in general), and because people are often drawn to the romance of vineyards, and wine production, there is more interest in the farming of wine grapes than say turnips or spuds.
A recent 4 year study led by Dr. Daniel R. Cayan, of Scripps Institution of Oceanography at UC San Diego, found that average temperatures had only increased by a degree or two (Fahrenheit) over the past several decades, mainly affecting overnight temps rather than daytime temps. That really doesn't surprise me, especially seeing as it is possible for the diurnal/nocturnal temperature differential in Napa to be as much as 40 -50 degrees.
Vinoland's Cabernet sauvignon vines are approximately 80% through veraison. Due to persistent cool temperatures (our second below average summer in a row), it's hard to tell if my pruning experiment this year has had any impact on the maturation of the Cabernet vines. With possibly two full months still until harvest I can only cross my fingers and hope for warm, dry weather during September and through October.
Whilst I do understand that the San Francisco Bay Area is well known for it's diverse micro climates - and it is indeed the cool marine layer that aids in quality grape production in this part of the world - I long for more typical summer temps...it is California after all.
Global warming is awfully cold!