Forests play a more significant role in removing carbon from the atmosphere than first reported by absorbing one-third of carbon emissions annually, a new U.S. Forest Service study says.


“Forests provide us with abundant clean air,” said U.S. Forest Service Chief Tom Tidwell. “This study shows the important role global forests play in keeping the air clean and it also broadens our understanding of how climate change relates to forest management in today’s world.”


Forests absorb carbon like a giant sponge into what scientists call a carbon sink. Oceans serve as the only other natural source for absorption of significant amounts of carbon. Until these new findings, many experts said forests played a less important role in removing carbon from the air we breathe. Today’s report indicates otherwise.


The study, conducted by the U.S. Forest Service’s Northern Research Station and a team of scientists from around the world, was recently published in the journal Science online, at the Science Express website, an online publication of the nonprofit American Association for the Advancement of Science.


One of the key findings in the study is that global forests have annually removed 2.4 billion tons of carbon and absorbed 8.8 billion tons of carbon dioxide from the atmosphere, or about one-third of fossil fuel emissions annually from the period of 1990-2007.


“The new information suggests forests alone account for the most significant terrestrial carbon sink, and that non-forest lands collectively cannot be considered a major carbon absorption sink,” said Dr. Yude Pan, a U.S. Forest Service scientist and a lead author of the study.


The study reveals the dominant role of tropical forests. Tropical forests that have not suffered from deforestation absorb enormous amounts of carbon, more than all other northern hemisphere forests combined. The analysis also identified an additional large carbon uptake of 1.6 billion tons per year in tropical re-growth forests that are recovering from deforestation and logging, which partially compensates for a large carbon source from tropical deforestation.


The study also highlights the risk of passively relying on forests to continue to remove carbon from the atmosphere. Such carbon sequestration is reversible through increased drought, wildfire and forest degradation.