The impact of human activities on the atmosphere and the accompanying risks of long-term global climate change arises mostly from the increase in greenhouse gas (GHG) concentrations due emissions from fossil fuels. However, globally about one-third of the total human-induced warming effect due to GHGs comes from agriculture, land-use change and forestry.

The 2001 IPCC Third Assessment Report concluded that the poorest countries would be hardest hit by climate change, with reductions in crop yields in most tropical and sub-tropical regions due to decreased water availability, and new or changed insect pest incidence. In Africa and Latin America many rainfed crops are near their maximum temperature tolerance, so that yields are likely to fall sharply for even small climate changes; falls in agricultural productivity of up to 30% over the 21st century are projected. Marine life and the fishing industry will also be severely affected in some places.1

The agricultural sector has the potential not only to reduce these emissions but also to significantly reduce net GHG emissions from other sectors. The agriculture sector’s contribution to achieving GHG reduction goals will depend on economics as well as available technology and the biological and physical capacity of soils to sequester carbon. The level of reductions achieved will, consequently, strongly depend on the policies adopted. In particular, policies are needed to provide incentives that make it profitable for farmers to adopt GHG-mitigation practices and to support needed research.

Recommendations:

• Increased soil carbon
• Cropland management and sequestration
• Use of high-residue crops and grasses
• Efficient use of manures, nitrogen fertilisers, and irrigation
• Grazing land and hayland management
• Land-use changes to increase soil carbon
• Total agricultural soil carbon sequestration potential
• Reducing agricultural nitrous oxide and methane emissions
• Use of bio-based materials
• Micro-irrigation systems
• Use of natural pesticides

The agricultural sector can reduce its own emissions, offset emissions from other sectors by removing CO2 from the atmosphere (via photosynthesis) and storing the carbon in soils, and reduce emissions in other sectors by displacing fossil fuels with biofuels. Through adoption of agricultural best management practices, farmers can reduce emissions of nitrous oxide from agricultural soils, methane from livestock production and manure, and CO2 from on-farm energy use. Improved management practices can also increase the uptake and storage of carbon in plants and soil. Every tonne of carbon added to, and stored in, plants or soils removes 3.6 tonnes of CO2 from the atmosphere. Furthermore, biomass from the agricultural sector can be used to produce biofuels, which can substitute for a portion of the fossil fuels currently used for energy.2

However there are real concerns about the current rush for biofuels which are leading to:
• mass deforestation in developing countries
• rise in cereal prices and danger of starvation
• priority of land use to grow biofuel than crops to eat
• increase in unrest due to food scarcity

Notes

1. http://en.wikipedia.org/wiki/Climate_change_and_agriculture
2. Pew Centre on Global Climate Change, ‘Agriculture’s role in greenhouse gas emissions’