A new report led by researchers at Winrock International, a U.S. environmental nonprofit organization, has developed an estimate of gross carbon emissions from tropical deforestation for the early 2000s that is considerably lower than other recently published estimates.
The study combined the best available spatially consistent datasets on gross forest loss and forest carbon stocks to track emissions from deforestation in millions of individual map pixels. Their methods focus on carbon losses to the atmosphere and do not include regrowth, which sequesters carbon from the atmosphere. The resulting gross emissions estimate of 0.81 billion metric tons of carbon emitted per year, with a statistically derived 90 percent prediction interval of 0.57-1.22 billion metric tons, is approximately one third of previously published estimates and represents just 10 percent of total global anthropogenic carbon emissions over the time period analyzed. Two countries – Brazil and Indonesia – produced the highest emissions between 2000 and 2005, and accounted for 55 percent of total emissions from tropical deforestation. Nearly 40 percent of all forest loss in the study region was concentrated in the dry tropics, but accounted for only 17 percent of total carbon emissions, reflecting low carbon stocks in these forests compared to tropical moist forests.
Policies to reduce emissions from deforestation would benefit from clearly derived, spatially explicit, statistically bounded estimates of carbon emissions. Existing efforts derive carbon impacts of land-use change using broad assumptions, unreliable data, or both. We improve on this approach using satellite observations of gross forest cover loss and a map of forest carbon stocks to estimate gross carbon emissions across tropical regions between 2000 and 2005 as 0.81 petagram of carbon per year, with a 90% prediction interval of 0.57 to 1.22 petagrams of carbon per year. This estimate is 25 to 50% of recently published estimates. By systematically matching areas of forest loss with their carbon stocks before clearing, these results serve as a more accurate benchmark for monitoring global progress on reducing emissions from deforestation.
Harris N L, Brown S, Hagen S C, Saatchi S S, Petrova S, Salas W, Hansen M C, Potoapov P V and Lotsch A (2012). Baseline Map of Carbon Emissions from Deforestation in Tropical Regions, Science 336, 6088, 1573-1576 DOI: 10.1126/science.1217962
To read Winrock International’s press release on the study see here.
To access the article see here.