Implications of a Global Climatic Warming for Agriculture: A Review and Appraisal

Recently it has been recognized that changes in the chemical composition of the atmosphere are likely to alter the earth's climate, and that these alterations may have severe implications for agriculture and other economic activities. This has stimulated research into the possible consequences of altered climatic regimes on several attributes or components of agri-food systems. Current consensus suggests that a global climatic warming, induced by increased concentrations of CO₂ and other “greenhouse” gases, is likely, and hence the possible implications of warmer climates for agriculture has received considerable attention. Several analytical procedures have been employed in these studies and it is timely to assess the characteristics and achievements of these independent efforts. This paper classifies and reviews studies that examine the implications of climatic warming for agriculture. Three approaches to assessment are recognized. Crop yield analysis identifies the effects of a specified change in climate on productivity levels for individual crops in particular locations. Spatial analysis examines the implications of climatic warming for the area and location of lands suitable for crop production. Agricultural systems analysis focuses on the relationships among components of agri-food systems. Much remains to be learned about the effects of climatic warming on agriculture. The use of existing information to develop a comprehensive analysis is hampered by differences in analytical approaches and in climatic change scenarios, and by the virtual absence of information on the possible implications of climatic change on agriculture in developing nations. Nevertheless, current evidence suggests that a warmer climate could create a more favorable environment for wheat (Triticum aestivum L.) and grain corn (Zea mays L.) in Canada, Northern Europe, and the USSR, and restrict opportunities in the USA. Contribution from LEG, Univ. of Guelph. Research was conducted at the Univ. of Guelph and supported by the Atmospheric Environment Service of Environment Canada, the Social Sciences and Humanities Research Council, the Ontario Ministry of Agriculture and Food, and the Land Resource Research Centre of Agriculture Canada.