By the end of the century, up to 81 percent of the country’s high-to-premium end wine grape production zones will decrease. That’s because by 2050, temperatures will increase by an average of 3.6 degrees across 27 of the U.S.’s wine regions. By 2100, that number will have increased to 4.5 degrees in the western part of the country.

In addition, the global winegrowing regions’ already over-allocated water supply systems will be extremely taxed. Also, because of planetary warming, we’re going to see a heavy increase in the number of insects and also the introduction of species that we’ve never seen before. This, in turn, will result in plant resistance in the varieties on which those insects feed. As a consequence, different cultivars or grapevine varieties will have to be developed.

Those dramatic and dire predictions were put forth recently by a trio of scientists at the Unified Wine & Grape Symposium in Sacramento. The University professors presented their case on the controversial subject of climate change as it pertains to the wine industry.

Dr. Greg Jones, a climatologist at Southern Oregon University, further predicted that we’re going to experience warmer and longer growing seasons, longer dormant periods and altered ripening profiles.

Jones and other climatologists have been weighing in quite heavily and vociferously on what warmer temperatures will bring. But others, such as entomologists and environmental scientists are now beginning to introduce their notions concerning the collateral issues of how insects and water will affect wine grape growing in the future.

“Insects don’t have the ability to control their temperature. As it warms up, we’re going to see an incredible increase in the number of insects,” predicted John Trumble, an entomologist at the University of California, Riverside. Trumble was speaking to a group of about 250 wine industry types in the California capital.

“This is going to be very exciting,” he concluded, with only a touch of irony. “If we get more monsoonal rains coming up from Baja, we’re going to see a dramatic increase in species of insects in California that we’ve never seen before.”

Trumble went on to say that, as periods of weather become warmer, the effect will be to impede the diapauses or hibernation cycle of those insects, and subsequently, they’ll live longer. The astonishing result will be the introduction of new grape vine varieties.

Robert Wilkinson, an environmental scientist at the University of California, Santa Barbara, warned that climate change will bring shortages of water.

“We’re already figuring out how to work with less,” he said as he cited the fact that much of the country’s water supply in wine growing regions comes from snow pack. Alas, he cautioned, “We’re going to get more rain – and less snow.”

He concluded that water systems throughout the winegrowing world will “have scarcity and stress. Managing groundwater will have to get better; recycling will have to increase.”

Greg Jones has an answer for the naysayers, who, interestingly, continue to pooh-pooh the ever-mounting evidence.

• The year 2005 was the warmest recorded year in the U.S. in the 150 years that such records have been maintained.


• Each of the last nine years has been among the 25 warmest on record here.


• Globally, each of the last 15 years has been in the top 25 hottest years on record.

To those nonbelievers, Jones said, “We’re going to see more hot and cold weather” in the foreseeable future.

“As a climatologist, 15 years ago I was on the fence,” he admitted, referring to climate change. “Today, I’m no longer on the fence. Climate in the future will be different than it is today. That’s clear.”

Jones has studied viticulture climate data from 1948 to 2004 and found an increase in average growing-season temperatures worldwide of 2.3 degrees. He suggested that, “It is very hard for humans to conceive how climate was in the past.

“You say 2006 was the coldest growing season? (So) maybe we need to get to a crisis in order to do something about it. … We need to go there, but we need to get beyond economic and political issues. … The question is how we can adapt and mitigate (climate change). We have to be aware of adapting, before we adapt at all.”

Need we say more.

~ Alan Goldfarb, Regional Correspondent


To comment on Alan’s writings and thoughts, contact him at a.goldfarb@appellationamerica.com

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Illustrations courtesy of: White, M.A., Diffenbaugh, N.S., Jones, G.V., Pal, J.S., and F. Giorgi (2006). "Extreme heat reduces and shifts United States premium wine production in the 21st century". Proceedings of the National Academy of Sciences, 103(30):11217*11222