New research suggests tropical forests are absorbing more carbon dioxide than researchers previously predicted.
The findings suggest tropical forests absorb 1.4 billion metric tons of carbon dioxide, compared to a total global absorption of 2.5 billion, NASA's Jet Propulsion Laboratory reported. The study represents the first "apples-to-apples" comparison of carbon dioxide estimates from multiple sources including computer models and satellite images.
"This is good news, because uptake in boreal forests is already slowing, while tropical forests may continue to take up carbon for many years," said David Schimel of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Schimel is lead author of a paper on the new research, appearing online in the Proceedings of National Academy of Sciences.
As man-made emissions spew carbon dioxide into the atmosphere, forests are utilizing it to help them grow faster and remove even more greenhouse gas from the air. The problem is wildfires and wood burning imposed by deforestation can release huge quantities of carbon dioxide back into the atmosphere, contributing to global warming.
"All else being equal, the effect is stronger at higher temperatures, meaning it will be higher in the tropics than in the boreal forests," Schimel said.
Past models have shown mid-latitude forests in the Northern Hemisphere absorb more carbon dioxide than tropical forests, but measurements taken from aircrafts disputed that theory. These new findings back up the idea that tropical forests are actually making a greater impact on carbon dioxide absorption.
"What we've had up [until] this paper was a theory of carbon dioxide fertilization based on phenomena at the microscopic scale and observations at the global scale that appeared to contradict those phenomena. Here, at least, is a hypothesis that provides a consistent explanation that includes both how we know photosynthesis works and what's happening at the planetary scale," Schimel concluded.
