Cayambe, via Wikimedia Commons
Tropical forests such as this one in French Guiana may play a bigger role in slowing climate change than previously believed.
If you’re worried about climate change, the recent news that 2014 was the hottest year on record didn’t help your anxiety. But here’s at least one positive bit of news to ease your mind a little. Researchers have discovered that tropical forests -- in reaction to rising atmospheric levels of carbon dioxide -- may be absorbing far more of the greenhouse gas than previously believed.
A NASA-led study, published in Proceedings of the National Academy of Sciences, estimates that tropical forests annually absorb 1.4 billion metric tons of carbon dioxide out of a total global absorption of 2.5 billion metric tons. That’s more than is absorbed by the boreal forest in Canada, Siberia and other northern regions, the researchers say.
“This is good news, because uptake in boreal forests is already slowing, while tropical forests may continue to take up carbon for many years,” lead author David Schimel of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., said in a press release.
The planet’s wooded areas have been a big part of slowing the effects of increased human output of carbon dioxide, a process called sequestration. Trees remove CO2 from the atmosphere during photosynthesis, storing some of it in their wood and leaves, and transferring some to the soil through their roots, as this article from the U.S. Forest Service’s website explains. Forests and other vegetation take care of about 30 percent of human carbon emissions. But if that rate of absorption ever slows, the the rise in global temperature would speed up as a consequence.
For the past quarter-century, climate scientists have believed that the northern forests were sequestering more carbon dioxide than the tropical forests, based upon what was then understood about global air flow, and the belief that massive deforestation in tropical areas was causing those forests to emit more carbon than they were storing. But in the mid-2000s, Britton Stephens of the National Center for Atmospheric Research, who is another of the study’s co-authors, studied measurements made by aircraft and concluded that existing climate models were underestimating tropical forests’ carbon absorption. This new study builds upon that view.