Climate Change and Global Crop Production

• Harald von Witzke, chair for International Trade and Development at Berlin's Humboldt University, notes global warming will bring longer growing seasons to the world's northernmost and southernmost latitudes, thanks to increases in precipitation and atmospheric carbon dioxide. However, the decline in crop yields throughout most of the world will offset regional increases. Cline found climate change would hit poorer nations disproportionally hard, creating a 10 to 25 percent shortfall in agricultural output throughout the developing world, and nations such as India and Sudan could experience catastrophic shortfalls of up to 40 and 56 percent, respectively.
  
  

Precipitation Change Effects

• In their October 2008 article for Iowa State University's "Ag Decision Maker," Takle and Hofstrand examined Intergovernmental Panel on Climate Change data and estimated precipitation will decline in Europe, Central America and the central United States throughout the 21st century, leading to heavy grain production shortfalls. They also found that precipitation increases in China and East Asia will threaten to inundate crops and flood farmland. Irrigation can only ease the problem temporarily, as groundwater reserves are finite and no nation can afford to deplete its drinking water supply.
  
  

Deforestation

• Von Witzke notes subsidizing crops for green biofuels reduces available farmland for subsistence crops, driving farmers in developing nations to raze forests for arable land. This offsets any climate benefits from biofuel production, as Earth's forests are natural carbon sinks, making deforestation a major cause of global warming. In an interview with "Scientific American," Werner Kurtz, senior research scientist with National Resources Canada, articulates the scope of the damage by noting deforestation contributes more to climate change than humanity's total fossil fuel use for transportation.
  
  

Mitigating Climate Change

• "Scientific American" notes that no-till farming, in which farmers leave stalks on the soil to naturally degrade after harvest, can reduce carbon dioxide emissions by allowing the carbon within the biomatter to seep into the soil, rather than being released into the atmosphere. Bruce McCarl, distinguished professor of agricultural economics at Texas A&M, indicated in an interview with "Scientific American" that greenhouse gas emissions would decline if humanity began a mass shift to a vegetarian diet, as America alone devotes half of its farmland to produce animal feed.