Three important studies were initiated in the 1970s to investigate the relation ship between climatic variations and agriculture: by the National Defense University (1980) on Crop Yields and Climate Change to the Year 2000, by the U.S. Department of Transportation (1975) on Impacts 0/ Climatic Change on the Biosphere and by the U.S. Department of Energy (1980) on Environmental and 0/ a Possible CO -Induced Climatic Change (the ClAP Societal Consequences 2 study). These were pioneering projects in a young field. Their emphasis was on measuring likely impacts of climatic variations rather than...