Eating in a Warmer World

Technological advances in agriculture have improved crop yields dramatically over the past fifty years.  However, this increase in production has been matched by increase in global population, which has more than doubled since the 1950s.  In order to feed this growing population, we must continue to produce more food by both intensifying and expanding agricultural.  Food production is highly sensitive to climactic variability, therefore higher global temperatures, changes in the hydrological cycle, and increased probability of droughts and floods caused by climate change, now threaten our food security (Sacks & Rosenzweig, n.d).  Due to the complexity of the agricultural and socioeconomic systems that determine food supply and demand, it is difficult to
predict exactly how the production of food will be effected by these climactic changes, but it is clear that we will see dramatic shifts in the agricultural system in the coming years (Rosenzweig & Hillel, 2004).

Several factors are expected to have a significant effect on agriculture:
  • Average global temperature increase
  • Change in amount and distribution of rainfall
  • Elevated levels of CO2 in the atmosphere
  • Increased probability of weather disasters such as droughts and floods (“Agriculture”, 2007)

Although yields may be increased by warmer climates in certain regions and higher CO2 levels may stimulate more rapid growth in crops, such as wheat, rice, and soybeans, the overall net effect of climate change on food production will be negative (Lobell & Field, 2007).
  Food production in higher latitudes may be stimulated by warmer temperatures and longer growing seasons, however, areas in where crops are grown close to their heat tolerance level, any increase in temperature would be detrimental to food security.  In addition, the damage caused by heat waves, drought, floods, and hurricanes will have an enormous impact crop yields and livestock worldwide.

It is predicted that yields will drop between 3-5 percent for every 1 degree F increase in temperature (Lobell & Field, 2007).

The implications for the developing world are most dire, because so much of the third world is concentrated in warmer regions near the equator where the effects of warming will be most disastrous.  The yield decreases will be the greatest in many of these underdeveloped areas, because they do not have the means to invest in technologies that would counter the negative effects of global warming.  Changes in methods, such as more efficient irrigation, drought and heat resistant genetically altered crops, and more effective fertilization are costly alternatives to traditional agriculture, and not available to most populations in the developing world.  Yield decreases caused by changing temperature cannot be offset in the developing world, as they might be in more advanced nations, because impoverished countries cannot afford to import food from areas of the world less effected by climate change.  The large percentage of populations in developing worlds which depend on agriculture as their main source of income will sink further into poverty as their yields are stressed by the changing weather.  Developing nations who can invest in progressive technologies and import food from other areas will be better off in a food crisis, but as food prices rise, the lower income populations in these countries will suffer as well (Parry, 2007).

One of the main sources of anthropogentic climate change are the elevated levels of greenhouse gases in the atmosphere.  Modern industrial agriculture is responsible for a large percentage of these emissions.  Carbon dioxide is released into the atmosphere as massive amounts of fossil fuels are burned in the production and transportation of food.  An incredible amount of methane is produced by animals bred for human consumption, and nitrous oxide is are emitted when large amounts of nitrogen fertilizer are applied to fields.  These emissions are further elevated by the reduction in the global carbon fixing potential as natural ecosystems are destroyed by deforestation and pollution.

The imminent food crisis is not singularly driven by yield decreases caused by global warming.  This is only a small piece of the puzzle.  Population growth is at the heart of food shortages and hunger, because as the population grows new sources of food must be found to feed hungry mouths.  The distribution of wealth and agricultural resources is also a key factor when considering world hunger.  Food is overabundant in many developed countries, such as the United States, where the population is plagued by heart disease and diabetes, caused by obesity.  On the other hand, populations in the Third World are suffering from malnutrition and starvation because of massive food shortages.  The urbanization of agricultural land, as well as the use of agricultural commodities to produce ethanol in response to the energy crisis, have both restricted land available for food production and caused increases in food prices worldwide.

Although climate change will drastically effect the production of food during the next century, we must also address these other concerns if we hope achieve to food security in the future.

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Last Updated Tuesday, December 9, 2008.