Definitive Tropical Forest Emissions Study Released

Falmouth, Mass. – The great forests of the tropics hold one quarter of all of the carbon stored in living organic matter.  What happens to these forests can significantly impact the global climate system.  A new study co-authored by Woods Hole Research Center scientists Scott Goetz, Alessandro Baccini, and Richard Houghton is the first to provide a clear picture of carbon emissions from tropical forest losses.

According to Dr. Goetz, “The work reported here provides the first estimates of pantropical emissions using good practice guidance of the Intergovernmental Panel on Climate Change, and it does that for a 12-year observational period. This information is key to tropical forest nations reporting their emissions in the context of the United Nations Reducing Emissions from Deforestation and forest Degradation (UN-REDD+) program.”

The team of scientists found Latin America to be the largest contributor to aboveground carbon (AGC) emissions from both forest clearing and natural forest loss.  (Natural forest loss includes losses from processes like fire and drought, which may be increased by human-caused climate change). Brazil accounts for the highest AGC loss for both categories at the national scale. The researchers estimate gross tropical forest carbon forest loss and natural forest carbon loss to account for 11% and 6% of global year 2012 CO2 emissions, respectively.

validation samples

Forest loss in natural and managed forests. Sample locations classified as reference loss within natural and managed forests for each of the seven forest types: 1—low cover; 2—medium cover short; 3—medium cover tall; 4—dense cover short; 5—dense cover short intact; 6—dense cover tall; 7—dense cover tall intact.

“Compared with the previous studies, we found significantly more tropical forest carbon loss in Africa and Southeast Asia. Our sample-based approach allowed us to target small-scale forest disturbances in Central Africa and Mainland Southeast Asia, which were previously underestimated” said University of Maryland Research Associate Alexandra Yurievna Tyukavina, the lead author of the study.

The researchers’ new estimate employs recommended good practices to quantify gross tropical forest AGC loss from 2000 to 2012 through the integration of satellite derived tree canopy cover, height, intactness and forest cover loss and lidar derived forest biomass. The sample-based results separate the gross loss of forest AGC into losses from natural forests and losses from managed forests including plantations, agroforestry systems and subsistence agriculture.

This work is especially significant as scientific consensus on this topic was previously lacking. “Given recent trends, natural forests will likely constitute an increasingly smaller proportion of tropical forest GHG emissions and of global emissions as fossil fuel consumption increases, with implications for the valuation of co-benefits in tropical forest conservation,” said Professor Matthew C. Hansen of the University of Maryland, a lead author on the paper.

The study, “Aboveground carbon loss in natural and managed tropical forests from 2000 to 2012” appears in Environmental Research Letters.

Link to abstract »

WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.