Saturday, April 30, 2005

After Which, the Grasshopper Kills the Ants 

The end of oil may not be the largest problem we have to face in the next few decades. New research indicates that, when it comes to the impact of climate change on worldwide food production, the most pessimistic forecasts to date are not pessimistic enough:
The higher temperatures and more frequent droughts caused by climate change are widely expected to depress crop yields in many places, especially the tropics. But this ought to be offset by faster photosynthesis caused by rising atmospheric concentrations of carbon dioxide, and laboratory tests had suggested that this beneficial effect could often dominate.

No such luck, says Stephen Long, a crop scientist at the University of Illinois at Urbana-Champaign. In open-field experiments with maize, rice, soybean and wheat he found that adding extra CO2 led to a beneficial effect only half as great as indicated by the lab experiments. Worse, when he added doses of ozone to the fields, to simulate the expected rise in ozone smogs due to higher temperatures, yields fell further. He says forecasters will need to make "a substantial downward revision of future global food production".

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