'Agriculture', in Climate change 2007: mitigation

This contributory chapter of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) outlines the status of climate change mitigation in agriculture and its implications on development, production and consumption trends. It presents regional and global trends in greenhouse gas emissions, as well as future global trends. The chapter breaks down numerous examples of proposed climate mitigation measures, including a table outlining whether each measure has a positive or negative mitigative effect on levels of greenhouse gases (CH2, CH4 and N2O), as well as a grade for the level of scientific agreement and amount of evidence available. The measures divide into the following seven categories. Cropland management: examples include the benefits of set-asides, land use changes and water management in mitigating N2O. Pasture improvement: examples include grazing intensity, fire management and species introduction, though none of these feature highly with regard to evidence or agreement of benefits. Management of organic soil: while avoiding the drainage of wetlands may help mitigate CO2 levels, it is likely to have a negative effect on CH4 mitigation. Restoration of degraded lands: this involves erosion control and organic and nutrient amendments. Livestock management: measures such as improving feeding practices, dietary additives and longer term structural changes in management and breeding can aid CH4 and N2O mitigation. Biosolid management: this includes improved storage and anaerobic digestion. Bioenergy: examples include a variety of sources for biofuel, such as energy crops and agricultural by-products. The authors discuss the interactions of mitigation options with adaptation and vulnerability, followed by the potentials, barriers and implementation issues of climate policies and the effects of non-climate policies on greenhouse gas emissions. The chapter highlights some co-benefits and trade-offs of mitigation options, again with a substantial table breaking down mitigative effects by emission type. The chapter finishes with a look at technology research and diffusion and a long-term outlook, which concludes that the prospects for greenhouse gas mitigation in agriculture hold significant potential.