Agriculture

Agricultural Impacts of Climate Change

Given that crops and livestock thrive in a relatively narrow set of environmental parameters, it makes sense to explore how climate change will affect agricultural productivity. Factors considered include the impacts of rising temperatures, increased production of carbon dioxide (CO2) and other greenhouse gases, water supply fluctuations, soil quality variations, sea level increases, and the introduction of new pests, diseases, and weeds that could hurt agricultural output. These changes can have different impacts, depending on the geographic scale of analysis, including local, regional, and global scales. Impacts will also vary according to the agricultural products under consideration. Some plant or animal species may be very resilient to environmental changes. Others may not adapt so well.

Temperature increases will affect crop and livestock production in various ways. A warming climate will extend the frost-free growing season at higher latitudes. Regions that are too cold to support commercial agriculture in northern Canada, Alaska, Scandinavia, and Russia may become viable agricultural areas if temperatures increase. On the other hand, temperature-sensitive crops may no longer be commercially viable in regions that become too hot or dry. Rising temperatures could also increase heat stress on livestock.

Climatic change models predict that regional temperature variations may alter precipitation patterns and the supply of water for agriculture. Areas that are too dry may receive more moisture in the future. Areas that are productive without irrigation [Page 16]may suffer because as temperatures increase, so does the rate of plant evapotranspiration. Farmers will have to find ways to offset the rising temperatures and corresponding moisture loss if they are to survive. Furthermore, many meteorologists suggest that weather events such as thunderstorms, tornadoes, and hurricanes may become more intense and occur with greater frequency, bringing more rain to some regions. However, severe storms also cause strong winds and flooding, which could cause large-scale crop damage.

Many areas of the world, such as the Indian subcontinent, the Andes region of South America, Kazakhstan, California, and the American high plains rely on melt water from glaciers and heavy winter snows to feed rivers, which in turn provide water for irrigation. These high-altitude water sources have traditionally been viewed as renewable resources that provide reliable moisture during the growing season and are replenished by winter snowfall. However, rising temperatures have caused many glaciers to shrink or disappear and have been linked to reduced snow pack at high altitudes. This means less water for agricultural regions located downstream.

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