Thursday, February 17, 2011

Climate Change and Crop Yields

Stuart Staniford takes on pundits claiming that global warming is causing food shortages:
So, clearly, the overwhelming story in global agricultural yields is this: improving agricultural technology has increased yields at a steady, reliable pace - they have more than doubled over the last 50 years.  There just is absolutely no support in the data for the idea that climate change, or any other negative or scary factor you care to name - eroding soil, depleting aquifers, peaking oil supplies - is causing the agricultural yield curve to start bending downward.  Maybe they will in the future, but it sure isn't happening yet.

I would guess that with greater demand and tighter supplies comes the risk for major disruptions from a shift in global climate.  Will Ohio and Indiana begin to receive more rain on the poorly drained silty clay loams which make up the richest soils of the Eastern Corn Belt?  Will the 20-inch rain line move to the east and threaten the Western Corn Belt?  If the productive regions of the Midwest are affected in the long-term, there will be dramatic problems.  Could there be a multiyear drought in the Corn Belt?  Is that likely? I don't know. Australians are pretty concerned for the future of agriculture there.  The Imperial Valley could lose most of its irrigation water in the near future.  There are a number of potential threats to the food supply that may be caused by climate change in the future. 

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