Peter G.Peters International Institute for International Economics: Global Warming and Agriculture: Impact Estimates by Country -- by William R. Cline

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Global Warming and Agriculture: Impact Estimates by Country -- by William R. Cline

Unabated global warming will reduce global agricultural capacity at least modestly by late in this century, contrary to some estimates that it will benefit global agriculture over that period. The damages will be the most severe and begin the soonest where they can least be afforded: in the developing countries. The losses will be much larger if carbon fertilization1 benefits fail to materialize, especially if water scarcity limits irrigation.

Temperatures in developing countries, which are predominantly located in lower latitudes, are already closer to or beyond thresholds at which further warming will reduce rather than increase agricultural capacity, and these countries tend to have less capacity to adapt. Moreover, agriculture accounts for a much larger share of GDP in developing countries than in industrial countries, so a given percentage loss in agricultural potential would impose a larger income loss in a developing country than in an industrial country. This study starkly confirms the asymmetry between potentially severe agricultural damages in many poor countries and milder effects in rich countries. A small amount of warming through, say, the next two or three decades might benefit global agriculture (with some countries gaining more than others). But it would be a serious mistake to do nothing about global warming on grounds that some studies have estimated global agricultural gains rather than losses for the first few degrees of warming.