Boosted carbon emissions from Amazon deforestation

Standing biomass is a major, often poorly quantified determinate of carbon losses from land clearing. We analyzed maps from the 2001-2007 PRODES deforestation time series with recent regional pre-deforestation aboveground biomass estimates to calculate carbon emission trends for the Brazilian Amazon basin. Although the annual rate of deforestation has not changed significantly since the 1990s ( ANOVA, p = 0.3), the aboveground biomass lost per unit of forest cleared increased from 2001 to 2007 ( 183 to 201 Mg C ha(-1); slope of regression significant: p < 0.01). Remaining unprotected forests harbor significantly higher aboveground biomass still, averaging 231 Mg C ha(-1). This difference is large enough that, even if the annual area deforested remains unchanged, future clearing will increase regional emissions by similar to 0.04 Pg C yr(-1) - a similar to 25% increase over 2001 - 2007 annual carbon emissions. These results suggest increased climate risk from future deforestation, but highlight opportunities through reductions in deforestation and forest degradation ( REDD). Citation: Loarie, S. R., G. P. Asner, and C. B. Field ( 2009), Boosted carbon emissions from Amazon deforestation, Geophys. Res. Lett., 36, L14810, doi:10.1029/2009GL037526.