Global Warming and Food Insecurity

Projected climate changes may adversely affect global and regional food security.

30.1.2.1 Greenhouse Gases and Food Security in Low-Income Countries

Climate change may impact food security in different ways. Some parts of the world — notably West Africa — have already been adversely impacted by climate change. Significant differences in regional food gaps may be explained at least in part by higher levels of agricultural productivity in Latin America and Asia as compared to Sub-Saharan Africa. A major challenge facing food-deficit regions is to address long-term issues, such as global climate change, while also dealing with shorter-term issues such as availability of fertilizers, farm machinery, land tenure, and so on.

30.1.2.2 Effect of Global Climate Change on Agricultural Pests

The manner in which climate change will impact the incidence of pests and diseases is a potentially important but understudied problem. Pest incidences may shift in response to climate change. The "standard model," based on temperature and precipitation, may be useful for studying impacts of climate change, but much more research needs to be done. Most crop models that are used to predict impacts of climate change on production fail to incorporate pests. The problem is compounded by the complexity of the climate processes. Nitrogen appears to have important effects on insect herbivores and on important species interactions that are not well understood. It is also important to disconnect the scale at which tests are impacted by climate change from the scale used for GCM models. Pest-climate interactions with climate change need to be assessed.

30.1.2.3 Impact of Climate Change on Agricultural Production in Different Regions

Projected climate changes could affect crop yields and soil carbon in different regions of the world. In fact, severe adverse impacts in the tropics could occur. Modeling studies based on data from Brazil show that changes in temperature and rainfall may result in soybean production increases and maize and wheat production decreases by 2050. In a case study of the Amazon Basin in which forested areas were converted to pastureland, the soil carbon pool was projected to decrease by 30% over a 100-year period. A decline in the SOC pool would have adverse impacts on soil quality and result in a decline in agronomic productivity and the capacity of the environment to moderate changes.

30.1.2.4 Modeling Future Climate Changes and Crop Production Scenario Challenges

The prediction of impacts of climate change on agricultural research and the use of crop models to assess the potential impacts of climate change suffer from several limitations. Crop models can result in accurate predictions when they are based on observed data, but are much less reliable when based on data that are downscaled from GCMs. A key limitation of GCM data appears to be an inability to represent extreme weather events, particularly those associated with precipitation. The hydrological cycle in the U.S. Midwest is not well represented by downscaled GCM data, because of nonlinear and feedback effects in more detailed regional climate models.

30.1.2.5 Policy Considerations Related to Twin Problems of Global Warming and Food Insecurity

There are major policy issues related to aspects of climate change. The world faces important food insecurity and global warming challenges in the 21st century. Previous research failed to suggest that global warming will have a large impact on aggregate food availability. However, it does suggest that global warming could have some major regional effects on food security, especially in the tropics, in which 800 million people are already at risk. The solution to the food security problem is to address the more fundamental problem of poverty. The "standard model," based on the "Washington consensus," may be the best starting point for economic development. This model emphasizes markets and institutions in infrastructure, education, and agricultural research. This model is not always used for political and cultural reasons. Nevertheless, past efforts indicate that an important step in promoting national food security is to develop economies to the point at which nations can afford to address environmental sustainability as well as economic growth.

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