Issue link: https://digital.copcomm.com/i/552044
92 { THE SOMM JOURNAL } AUGUST/SEPTEMBER 2015 { wine science } CLIMATE CHANGE IS A VERY REAL THREAT TO NOT ONLY VITI- culture but every living system worldwide. We discussed some general global trends in a previous issue, but here the focus will be on the effects of climate change on two very well-known wine regions in the United States: Washington and Oregon. Temperature Between 2000 and 2039, models are predicting growing degree day increases in the Willamette and Columbia Valleys from 100 to 200 days. (Growing degree days are a measure of heat accumulation used to pre- dict plant development rates, calculated by taking the average of the daily maximum and minimum temperatures compared to a base temperature.) Additionally, temperatures are predicted to increase between 0.6–0.7oC and 0.6–1.0oC in the Willamette and Columbia Valleys, respectively. Finally, the number of growing degree days over 35oC are expected to increase to upwards of 7.5 days in the Columbia Valley, while spring and fall mini- mum temperatures below -6.7oC are expected to decrease by 5 or 6 days in the same region. Frost In Washington and Oregon, the number of days with frost has decreased. Specifically, there are 18 fewer frost days per year on average than in years previous. Most of the reduction in frost days has been in the spring, though there also has been a smaller reduction in frost days in the fall. In general, Washington and Oregon are seeing earlier last frost dates than in the past, as well as longer frost-free periods throughout the entire growing season. Degrees of Separation Editor's Note: The effects of climate change on the global wine industry are not at all uniform. Each individual region may suffer its own unique effects, some of which will be described in more detail in subsequent articles in The SOMM Journal. This piece highlights the general effects of climate change on the wine regions of Washington and Oregon. CLIMATE CHANGE MAY BENEFIT WASHINGTON AND OREGON— WITH SOME CAVEATS by Becca Yeamans-Irwin Vineyards in Oregon, where climate change could eventually result in riper styles of Pinot Noir. PHOTO COURTESY OF THE OREGON WINE BOARD