Since international climate change negotiations began in the early 1990s, agriculture has been largely overlooked. This omission was perhaps understandable, given the knowledge of the time. Now, it no longer is. A growing body of evidence shows that the world’s farmers can play a significant role in reducing greenhouse gas emissions and thus contribute to efforts to mitigate climate change. But agriculture also faces serious challenges, and the global food supply will depend on how well agriculture adapts to climate change. As the world prepares for a possible new agreement on climate change in December 2009 in Copenhagen, it is time to put agriculture on the agenda.
When climate negotiations began more than a decade ago, the effects of climate change on agriculture appeared manageable: this is the main reason why agriculture is missing from many of the documents of the United Nations Framework Convention on Climate Change. No one said that agriculture would be unaffected by climate change. In the mid-1990s, however, the general consensus in the scientific community was that rising temperatures and changing precipitation patterns would push down yields in temperate regions and that these downward effects would be offset by trade flows from parts of the world with higher yields and by the fact that increased CO2 in the atmosphere can act as a crop fertilizer and thus boost yields.
In the early 2000s, climate scientists started to become concerned about crop production. They foresaw moderate increases in agricultural yields in developed countries and declines in developing countries, located mostly in tropical areas, and they perceived a substantially greater risk of hunger in the developing world. Nonetheless, most scientists still believed that CO2 fertilization and more trade flows could buffer the negative effects of higher temperatures and more varied precipitation. By the mid-2000s, concern was growing stronger, and increased reliance on CO2 fertilization and trade flows appeared essential to balance the negative effects in some locations.