EPIBuilding a Sustainable Future
Outgrowing the Earth: The Food Security Challenge in an Age of Falling Water Tables and Rising Temperatures

Chapter 7. Stabilizing Climate: Introduction

In July of 2004, the U.S. National Academy of Sciences released a research report by a team of nine scientists from China, India, the Philippines, and the United States who had measured the precise effect of rising temperatures on rice yields under field conditions. They concluded that yields typically fall by 10 percent for each 1-degree Celsius rise in temperature during the growing season. This confirmed what had seemed obvious to many agricultural analysts, namely that high temperatures can shrink harvests. 1

In recent years, numerous heat waves have lowered grain harvests in key food-producing countries. In 2002, record-high temperatures and associated drought reduced grain harvests in India, the United States, and Canada, dropping the world harvest 89 million tons below consumption. In 2003, Europe was hit by high temperatures. The record-breaking late summer heat wave that claimed 35,000 lives in eight nations shrank harvests in every country from France eastward through the Ukraine. It contributed to a world harvest shortfall of 94 million tons—5 percent of world consumption. 2

The new research results from agricultural scientists, along with the grain production performance of various countries recently exposed to record temperatures, underscore the close relationship between energy policy and food security. Farmers already struggling to feed 70 million or more people each year will find it even more difficult as the earth’s temperature rises. 3

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1. Shaobing Peng et al., “Rice Yields Decline With Higher Night Temperature From Global Warming,” Proceedings of the National Academy of Sciences, 6 July 2004, pp. 9971–75.

2. U.S. Department of Agriculture (USDA), Production, Supply, and Distribution, electronic database, at www.fas.usda.gov/psd, updated 13 August 2004; Janet Larsen, “Record Heat Wave In Europe Takes 35,000 Lives,” Eco-Economy Update (Earth Policy Institute), 9 October 2003.

3. United Nations, World Population Prospects: The 2002 Revision (New York: 2003).


Copyright © 2004 Earth Policy Institute