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17 April 2014 12:48 pm ,
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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Some Farmers Get Big Climate Boost
13 February 2003 (All day)
Since the 1940s, harvests across the United States have become ever more bountiful as farming technology has improved. But over the past 2 decades, farmers have had more than a little help: A new study shows that a surprisingly high percentage of the improvement in yield was due not to farm management but to climate change. The finding suggests that food production in the United States may be more sensitive to shifts in climate than was previously suspected, a fact that could affect global food security.
Graduate student David Lobell and Gregory Asner, both of the Carnegie Institution of Washington and Stanford University, investigated the interplay among temperature, rainfall, amount of sunshine, and corn and soybeans yields from 1982 to 1998. During this time, summers in a large swath of the Midwest became slightly cooler. Lower temperatures in the region are known to boost corn and soybeans yields, which rose about 30% over the study period. The United States leads the world in production of the two crops.
Lobell and Asner wanted to tease out the impact of those gradual climate shifts relative to other influences on yield, such as farming practices. To reduce the statistical noise, they picked counties throughout the United States where yields had responded to climate in the same way, either rising in cooler summers or falling in warmer ones. Using a statistical model to compare these climate variations among counties with changes in yield, the researchers found that the cooling climate was responsible for about 20% of the gains over the 17 years. The remainder they credit to management and other factors, such as increased carbon dioxide in the atmosphere.
"This points out that our food production may be more vulnerable to shifts in climate than we thought," says Jonathan Foley, a climatologist at the University of Wisconsin, Madison. Lobell and Asner's analysis, reported in the 14 February issue of Science, indicates that yields would drop by 17% for each degree that the growing season warms. That's three times as much as other studies have suggested. Most climate models predict that the Corn Belt of the U.S. Midwest will warm over the next few decades. Other experts point out, however, that many other aspects of climate could have an impact too.