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Crop Yield and Climate Change: A Ray of Hope

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nathan.jpgPundits publish dire warnings on the adverse impacts of climate change on food production: Shifts of temperature and precipitation around the world are creating frightening misalignments between farm management practices and weather, setting the stage for failed crops and food shortages.

Still, all may not be doom and gloom, says Nathan Mueller, a doctoral student in the Institute on the Environment's Global Landscapes Initiative.

It's true climate change has huge implications for agriculture, where the likelihood of success or failure leans more heavily than just about any other enterprise on the whims of weather patterns.

But wait just a minute, Mueller says. Scenarios that predict plunging yield as Earth warms assume farm management business-as-usual. Yet farmers always have modified their practices with climate's punches - planting early, harvesting late, irrigating more or less, modifying rotations and so on based on current conditions, predictions from elders, the Old Farmer's Almanac or the latest iPhone weather app. If they continue to adapt management to fit circumstances as they have in the past, couldn't climate change have far less of an adverse impact on food security than the worst-case scenarios, which don't factor in management changes?

Mueller and colleagues Jamie Gerber, Deepak Ray, Navin Ramankutty and Jon Foley have been exploring how improving crop management strategies could counter the negative effects of climate change on crop yields. In a poster presented at the American Association for the Advancement of Science (AAAS) meeting in Washington, D.C., in February (and recently selected as the best environment and ecology entry in the AAAS Student Poster Competition), they examined two scenarios of climate change and management improvement for corn and soybeans. One would bring the worst-performing landscapes up to average yields for their growing regions. The other would bring landscapes close to their best possible yields.

The researchers found that in the first case, global production will still be lower in 2050 than it is today due to changed climate, but less severely so than under the business-as-usual assumption. And if farmers achieved the more dramatic yield improvements that are possible with application of precision agriculture and other 21st-century yield-boosting tools, the researchers' models predict overall production would actually rise. The effect would be especially strong for regions where yields are far below capacity, such as sub-Saharan Africa; less so for places like America's Corn Belt, where production is already close to maximum possible given current crop varieties.

"In areas of the developing world where food security is most closely tied to agricultural production, potential yield changes attainable from intensification of maize and soy are likely to far outweigh the effects of changing average temperatures and precipitation," the poster concludes.

In other words, intensification of farm management can serve as a valuable strategy for adapting to a warming world, particularly in areas where there are much yield gains to be gotten.

"We don't need to just sit here and wring our hands," Mueller says. "In a lot of those regions, agriculture is so underdeveloped that even though they take a hit by climate change, agricultural development could overcome those losses and we could still see a net gain."

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  of the Institute on the Environment/University of Minnesota.