The experts from Stanford University and the National Center for Atmospheric Research found that the odds of a major production slowdown of wheat and corn, even with a warming climate, were not very high. But the risk was about 20 times more significant than it would be without global warming, and it might require planning by organizations that were affected by international food availability and price.
David Lobell, Stanford professor, said that whether the climate change would threaten food supply over a 10- or 20-year period largely depends on how fast the Earth warms and they can't predict the pace of warming very precisely.
Lobell and Claudia Tebaldi, NCAR scientist, used computer models of global climate, as well as data about weather and crops, to calculate the chances that climatic trends would have a negative effect of 10 percent on yields in the next 20 years. This would have a major impact on food supply. Yields would continue to increase but the slowdown would effectively cut the projected rate of increase by about half at the same time that demand was projected to grow sharply.
Global yields of crops such as corn and wheat have typically increased by about 1-2 percent per year in recent decades, and the U.N. Food and Agriculture Organization projects that global production of major crops would increase by 13 percent per decade through 2030. However, global demand for crops was also expected to rise rapidly during the next two decades because of population growth, greater per-capita food consumption, and increasing use of biofuels.
The study warned that although society could offset the climate impacts by planting wheat and corn in cooler regions, however such planting shifts to date have not occurred quickly enough to offset warmer temperatures. The researchers also found little evidence that other adaptation strategies, such as changes in crop varieties or growing practices would totally offset the impact of warming temperatures.
The study appears in this month's issue of Environmental Research Letters.