Conversion of forests into agricultural land is a major source of GHG emissions worldwide. Currently, a gross figure of 13 million ha of forests are lost annually, with net losses, allowing for afforestation and reforestation, at about 7.3 million ha y^-1. In the 1990s, degradation, defined as decrease of density or increase of disturbance in forest classes, affected tropical regions at a rate of 2.4 million ha y^-1. Deforestation releases an estimated 5.8 Gt CO₂ y^-1 into the atmosphere, both through the burning of the forest biomass, and from the oxidation of carbon stored in the soil under the trees during cultivation and in peatlands under drainage. Other GHGs, such as CH₄ and N₂O, may also be emitted during slash-and-burn and subsequent land use. This represents an estimated 17-20% of anthropogenic GHG emissions, greater than that from the whole global transport sector. Brazil and Indonesia are the countries with the highest net deforestation rates, losing 3.1 and 1.9 million ha of forest annually, and as such, total per capita CO₂ emissions in Indonesia, for example, may be 30% above the average for Europe, despite a much lower energy use

Stern (2007) concluded that reducing deforestation is a highly cost-effective way to reduce emissions relatively quickly, as well as providing co-benefits in terms of soils, water, climate protection, protection of biodiversity and livelihoods, rights of local communities, and sustainable forest management.

Macaulay scientists are investigating the causes of deforestation in the tropics, and evaluating ways in which this could be reduced, thereby contributing to reducing GHG emissions into the atmosphere.

Activities

• REDD: Reduced Emissions from Deforestation and Degradation – can people at the forest margins benefit from current UNFCCC proposals to include avoided deforestation in post-2012 climate change agreements?

• Analysis and synthesis of technical solutions in the forest agriculture interface – a review of technologies aimed at enhancing sustainability of subsistence farming at the forest margins

• Balancing ecosystem services: an agent-based approach to analysing tradeoffs between food production, carbon storage, and fuel production in tropical forests - poster presented at Food Security and Environmental Change Conference, Oxford, April 2-4, 2008.