ABSTRACT
The Fourth Assessment Report of the Intergovernmental Panel on Climate Change released in 2007 significantly increased our confidence about the role that humans play in forcing climate change. There is now a high degree of confidence that the (1) current atmospheric concentrations of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) far exceed those of the preindustrial era; (2) global increases in CO2 arise mainly from fossil fuel use and land use change, while those of CH4 and N2O originate primarily from agricultural activities; and (3) net effect of human activities since 1750 has led to a warming of the lower layers of the atmosphere, with an increased radiative forcing of 1.6 W m−2. Depending on the scenario of human population growth and global development, mean global temperatures could rise between 1.8 and 4.0°C by the end of the twenty-first century. The agricultural sector is likely to be significantly affected by regional changes in temperature and precipitation. Overall changes in crop productivity and global food production could be
Abstract ..................................................................................................................249 Introduction ............................................................................................................250 Climate Change Impacts on Agriculture ................................................................ 252
Plant Growth under Elevated CO2 ..................................................................... 252 Understanding the Effects of Elevated CO2 and Other Factors on Plant Growth ...............................................................................................................254 Predicting the Effects of Climate Change on Agricultural Productivity ........... 255
The Role of Agriculture in Climate Change Mitigation and Adaptation ............... 255 Definitions of Mitigation and Adaptation ......................................................... 255 Mitigation of Climate Change through Soil Carbon Sequestration and Reductions in Greenhouse Gas Emissions ........................................................ 257 Adapting Agriculture to Climate Change .......................................................... 259
Toward Agricultural Sustainability in the Twenty-First Century ........................... 259 Conclusions ............................................................................................................260
