Summary And Conclusions

Many people in low-income countries are food insecure. Research suggests that rising concentrations of greenhouse gases are likely to affect food security even more in the future. Some effects of greenhouse gases, such as CO2 fertilization, are likely to increase food security, while others, such as rising sea level, are likely to reduce food security. Of particular concern, however, are the potentially damaging effects of rising temperatures associated with global climate change. Countries in tropical and subtropical regions are especially vulnerable because they have temperatures that are already higher than optimal for crop production.

Results from this study suggest that climate change probably affected growing seasons in many low-income countries even during the 20th century. They also indicate that these changes probably affect food security in these countries as well. For example, climate change is estimated to reduce food security as early as 2012 in most of them, and in some, the impacts may be relatively large. However, the average total contribution of climate change to the total food distribution gap in low-income countries is probably very small. The data suggest that climate-induced changes in growing season probably interacted with the ENSO cycle as well. Some of these interactions would tend to exacerbate extreme events such as droughts in some countries.

The results of this study have implications for management options, policies, and research and development about carbon sequestration in developing countries. A decline in land quality usually leads to the conversion of nonagricultural land into agricultural uses, often in marginally productive areas. This typically triggers the release of carbon currently sequestered by other land covers into the atmosphere. Hence, management options that enhance food security by increasing agricultural productivity of existing agricultural land also may ensure continued carbon sequestration. Policies that are explicitly directed at carbon sequestration and that conflict with food security in developing countries will likely sequester less carbon than expected because of the ensuing expansion of agricultural land. In general, improving agricultural productivity tends to reduce land devoted to agricultural production (Ianchovichina et al., 2001). However, technological progress that substitutes capital for labor in labor-intensive agricultural systems can have the opposite effect, if the displaced labor is expelled to an agricultural frontier and begins clearing land (Angelsen and Kaimowitz, 2000, as reported in McNeely and Scherr, 2003).

Climate change is already occurring and is expected to continue throughout the 21st century. In addition to agricultural productivity, climate-induced changes in length of growing season also affect biological productivity in general. This in turn affects the accumulation and potential sequestration of terrestrial carbon. In general, longer growing seasons imply a greater ability to accumulate and sequester carbon and vice versa. But changing patterns of growing seasons over time at a given location may weaken the performance of management options or policies deemed suitable at their inception. This observation is particularly important when considering long-term carbon sequestration projects such as afforestation. One would want to plant trees, for example, that are compatible with the climate that is likely to occur over the time span of the project. Hence, consideration of the expected as well as the current climate, when evaluating management options, policies, and research and development designed to address carbon sequestration, will increase the probability of meeting program objectives.

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