Risks for US corn and grapevine productions in few decades

Climate changes influenced crop phenology. Plants are blooming earlier, birds are nesting sooner and mammals are breaking hibernation earlier than they were a few decades ago

by Aliona Avduhova

How global warming coul influence US crops?
Noah Diffenbaugh, an assistant professor of environmental Earth system science at Stanford University, answered with a study, presented at San Francisco few days ago.

The experiment focuses on the regional impact of climate change on agriculture in the United States over the next three decades, from wine grapes on the West Coast to maple syrup in the Northeast.

In a 2006 study, Diffenbaugh and his colleagues analyzed historical records from the principal wine regions of California, Oregon and Washington and found that temperatures in the growing season had increased about 1.6 degrees Fahrenheit (0.9 Celsius) from 1948 to 2002. Using these data and observations of how temperature affects the lifecycle of wine grapes, the researchers concluded that global warming could reduce the current U.S. wine grape region by 81 percent by the end of the century -- primarily because of a projected sharp increase in the frequency of extremely hot days where the temperature reaches 95 degrees Fahrenheit (30 Celsius) or above.

"A key question now is how soon will that severe heat emerge - Diffenbaugh said - In our new near-term climate projections, we're finding that the hottest temperatures on record will become commonplace within the next 30 years."

Diffenbaugh also used observational data in a 2008 study on U.S. corn production, which concluded that by the end of the 21st century, warmer growing seasons and milder winters could increase the population and geographic range of the corn earworm, an insect that preys on corn, tomatoes and other cash crops.

"In the case of agricultural pests, many of their ranges are limited by severe cold tempertaures - he said. - In our new simulations, we find that those temperatures could disappear over the next few decades, potentially leading to an expansion of pest pressure."

The Stanford research team is now using historical data to project the impact of climate change on maple syrup production in the northeastern U.S.