Climate Change Biggest Factor In Corn Price Increases
April 24, 2012

Climate Change Biggest Factor In Corn Price Increases

Jason Farmer for

A new study suggests that climate change could cause US corn prices to more than quadruple in years of peak volatility, environmental scientists said on Sunday.

The study, published in the journal Nature Climate Change, suggests that frequent heat waves will cause the sharp price spikes unless farmers develop more heat-tolerant corn varieties or gradually move corn production from the United States into Canada.

A study of the factors that drive up prices in the world's key market for corn found more frequent heat waves, as a result of global warming, proved to be much more of a determining factor than government policies to promote biofuels or than higher oil prices.

The analysis found that even a moderate warming trend could increase the number of days of severe heat during the growing season. This could lead to a doubling of the volatility of corn yields.

Based on data from agricultural, climatic and economic models, the study predicts that if climate change just remains within the internationally accepted range of two degrees Celsius over the next 20 years, those changes would make severe heatwaves far more common.

"Even one or two degrees of global warming is likely to substantially increase heatwaves that lead to low-yield years and more price volatility," Noah Diffenbaugh of Stanford University in California said in a press statement.

Climate scientists say warming by 2 C (3.6 F), as predicted by the UN, is underestimated.

The current trends of carbon emissions are placing Earth on a trajectory for warming of 3 C (5.4 F) or possibly more, according to some estimates. However, this figure is a global average, so it can be misleading in that it does not necessarily account for large regional variations, including seasonal bouts of extreme weather.

Prior to the results of the study, it was not clear to Diffenbaugh that climate change would be of more importance than either higher oil prices or government policies promoting biofuels.

"Frankly, I was surprised that climate had the largest effect of these three influences. These are substantial changes in price volatility that come from relatively moderate global warming," said Diffenbaugh.

However, practices of growing corn for fuel have removed a buffer of surplus grain.

"Our results suggest that energy policy decisions are likely to interact with climate change to affect corn price volatility, and that the market effect of a binding biofuel mandate is likely to intensify as the climate warms," notes Diffenbaugh.