ABSTRACT
Tracy Johns and Bernhard Schlamadinger Introduction In the 1990s tropical deforestation and other uses of land accounted, on average, for around 20 per cent of anthropogenic greenhouse gas (GHG) emissions. For the period from 2000-2006, the ‘residual terrestrial sink’ approximated to about 30 per cent of total anthropogenic emissions (Canadell et al., 2007). Representing, therefore, both a source of emissions and an important mechanism for reducing atmospheric GHG concentrations, forests in this dual climate role have been a constant source of debate and misunderstanding. In many ways, emissions from forest destruction can be treated like any other emission – from transportation or energy production, for example. All release CO2 into the atmosphere and, when it comes to the impact on global climate, unit for unit, the atmosphere does not distinguish among emission sources. However, there are important differences in measuring, monitoring and accounting for the carbon dynamics of a forest that require special treatment and that have, in the past, caused disagreement among policymakers over how to incorporate forests into global efforts to reduce GHG emissions.
