This contribution to GHG emissions makes efforts to reduce deforestation significant in international strategies to mitigate climate change. The existing data show little, if any, net deforestation in boreal and temperate forests, and thus the carbon consequences of deforestation in these ecosystems might not be significant. Under pending climate change legislation (e.g., H.R. 2454 , the American Clean Energy Act of 2009, and S. 1733 , the Clean Energy Jobs and American Power Act), Congress is considering providing resources for developing countries to establish programs and implement projects to reduce deforestation and forest degradation, and creating policy mechanisms to establish standards and markets for international offsets to reduce GHGs. International proposals focus on reducing emissions from deforestation and forest degradation (REDD) in developing countries. Biomass not removed for products remains on the site and decomposes. There are direct anthropogenic drivers of tropical deforestation, such as clearing for agriculture, as well as underlying causes, such as road construction, market forces, and government policies. Permanent small-scale agriculture is associated with about another third of agriculture-related tropical deforestation. The annual clearing of dense forest is related to the rural population density near the forest, suggesting that proximity of the populations and their access to forests is a major cause of deforestation in the region. This releases the carbon from the vegetation that is cut down. Forest and Deforestation Data Issues

Various sources report data on forest area and deforestation. Forests occur around the globe, at many latitudes. Many are concerned with the possible impacts of losing boreal and temperate forests. In contrast, the loss of tropical rainforests is substantial and ongoing, with significant climate impacts because of the large amount of CO 2 currently stored in vegetation in the tropics—40%-50% of the carbon in all terrestrial vegetation. Measuring forests is complicated. Forests are extensive and often inaccessible. In some places, the drivers are commercial logging, followed by slash-and-burn agriculture that may prevent regrowth of tropical forests. Elsewhere, the major cause of deforestation is large-scale commercial agriculture, especially for cattle ranching, soybeans, and oil palm. Deforestation may also result from weak land tenure and/or weak or corrupt governance to protect the forests. Further, reducing deforestation in the tropics would likely have ancillary benefits, including preserving biodiversity, providing livelihoods for rural poor, and sustaining indigenous communities and their cultures, among other things. Some forestry practices can reduce the impacts of net deforestation, and several market approaches are evolving that could compensate landowners for not deforesting their lands. Some of the challenges for implementing REDD programs include accurately and effectively monitoring REDD activities and projects and improving the capacity of developing countries to implement REDD programs and to ensure compliance. Evidence from past efforts to reduce deforestation as well as from existing data on forests and deforestation suggest this might be a significant challenge.
Efforts to mitigate climate change have focused on reducing carbon dioxide (CO2) emissions into the atmosphere. Some of these efforts center on reducing CO2 emissions from deforestation, since deforestation releases about 17% of all annual anthropogenic greenhouse gas (GHG) emissions and is seen as a relatively low-cost target for emissions reduction. Policies aimed at reducing deforestation are central points of a strategy to decrease carbon emissions, reflected in pending legislation in Congress (e.g., H.R. 2454 and S. 1733) as well as in international discussions, such as the December 2009 negotiations in Copenhagen.
Forests exist at many latitudes. Many are concerned about the possible impacts of losing boreal and temperate forests, but existing data show little, if any, net deforestation, and their loss has relatively modest carbon consequences. In contrast, tropical deforestation is substantial and continuing, and releases large amounts of CO2, because of the carbon stored in the vegetation and released when tropical forests are cut down.
There are many causes of tropical deforestation—commercial logging, large-scale agriculture (e.g., cattle ranching, soybean production, oil palm plantations), small-scale permanent or shifting (slash-and-burn) agriculture, fuelwood removal, and more. Often, these causes combine to exacerbate deforestation; for example, commercial logging often includes road construction, which in turn opens the forest for subsistence farmers. At times, tropical deforestation results from weak land tenure and/or weak or corrupt governance to protect the forests.
Congress and international bodies are discussing various policies to reduce carbon emissions from deforestation and forest degradation (REDD). Reducing deforestation in the tropics is likely to have additional benefits as well, such as preserving biological diversity and sustaining livelihoods for the rural poor and for indigenous communities and cultures. Proposals may be adapted to address local and regional causes of deforestation. Various forestry practices can reduce the impacts of deforestation, and several market approaches are evolving to compensate landowners for preserving their forests.
Many challenges remain for implementing REDD programs, particularly internationally, including monitoring REDD projects and improving developing-country capacity to ensure compliance. Existing evidence on forests and deforestation suggest the difficulties might be significant. Measuring forests is complicated, with multiple definitions, inaccessible sites, and expensive, complicated, and imperfect measurement technologies.
This report provides basic information on forests and climate change. The first section discusses the linkages between forests and climate. The next three describe the characteristics of the three major forest biomes, with an overview of deforestation causes and impacts. This is followed by an overview of approaches to reducing deforestation. The final section examines issues related to forest and deforestation data.