Carbon dioxide, climatic change and agriculture

• Published in: The Geographical journal 1988-07, Vol.154 (2), p.221-233
• Main Author: Warrick, R.A
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; agriculture; Agronomy. Soil science and plant productions; Bgi / Prodig; Biological and medical sciences; Carbon dioxide; Climate; Climate change; Climate models; Climatology, meteorology; Crop economics; Crop production; Crops; ecological zones; environmental impact statements; Food crops; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Techniques. Climatology. Meteorology. Climatic models of plant production; geographical distribution; Global climate models; greenhouse effect; growth; Human geography; Management of resources and environment; plant analysis; Plants; Political and economic geography; yield response functions
• ISSN: 0016-7398; 1475-4959
• DOI: 10.2307/633848

Higher ambient levels of carbon dioxide can affect crops directly, or indirectly through changes in climate. The results of controlled experiments consistently show that higher carbon dioxide increases dry matter production, largely by stimulating photosynthetic response, decreasing transpiration, and thus improving water use efficiency. Yields of C3crops (e.g. wheat), for instance, could increase by 10-50 per cent for a doubling of carbon dioxide concentrations. The sensitivity of crop yields to changes in climate variables have been investigated through several approaches-crop impact analysis, marginal-spatial analysis and agricultural systems analysis. Such investigations suggest that, for the core mid-latitude cereal regions, an average warming of 2°C may decrease potential yields by 3-17 per cent. Changes in climate at the margins of crop production could result in shifts in the geographical location of potential crop regions, perhaps of the order of several hundred kilometres per °C change in the mid and high latitudes. Agricultural systems analyses suggest that, to a large extent, the potential adverse effects of climatic change could be absorbed or avoided through agronomic, policy and market feedback mechanisms. Such results are only tentative. It is not yet possible to predict what the combined, net effect of both higher CO2and climatic change will be on global agriculture.