Deforestation accounts for less carbon emissions than previously thought, says NASA team.

A new study by a team at NASA has reduced estimates of the amount of carbon emitted due to tropical deforestation over the last decade. It suggests a 3 fold over estimate of the effect of tropical deforestation on carbon emissions. The difference between this and previous studies lies in the use of satellite data, which is much more refined than traditional ‘book-keeping’ analysis.

The study combined satellite data on forest loss and forest carbon to track emissions. The figure given was 0.81billion metric tons per year, which is one third of previous estimates and accounts for a tenth of overall anthropogenic carbon emissions in recent times. Brazil and Indonesia account for a majority of these emissions. There was also a stark contrast between the loss of dry and moist forest. Moist forest sequesters more carbon and therefore its loss produces greater emissions.

Both the researchers and other experts were quick to stress however, that the loss of millions of hectares of forest was ongoing and will still have a huge impact on emissions, biodiversity and the biosphere. "The relative contribution of deforestation to total greenhouse gas emissions will likely continue to decline through time as emissions from other sectors rise, but the loss of millions of hectares of forest per year remains considerable," said Alexander Lotsch of the World Bank, which funded the study.

"Effectively reducing forest-related emissions through international efforts that also promote biodiversity conservation, forest livelihoods and help maintain essential forest functions such as water regulation, is an essential measure to avoid serious climate change impacts and to ensure low carbon sustainable development in the developing world."

The focus will now turn to the most recent years that have not been part of the original study. It is hoped the analysis of the most recent period of data will show a decrease in emissions from deforestation.