WASHINGTON -- The effect of deforestation on climate depends on three things -- location, location, and location.
Environmentalists concerned about global warming have long encouraged preservation of forests because they absorb carbon dioxide, the most abundant greenhouse gas in the atmosphere.
But the issue may be more complicated than it first appears.
New research in this week's online edition of Proceedings of the National Academy of Sciences confirms the effectiveness of tropical forests at reducing warming by absorbing carbon. But it suggests that in snowy latitudes, forests may actually increase local warming by absorbing solar energy that would otherwise be reflected back out to space.
That doesn't mean forests in cold areas should be chopped down, stressed Ken Caldeira of the Carnegie Institution department of global ecology in Stanford, Calif.
"I am a little concerned about this being misapplied as an excuse to chop down the forests in the name of saving the environment," said Caldeira, a coauthor of the report.
"A primary reason we are trying to slow global warming is to protect nature. It just makes no sense to destroy natural ecosystems in the name of saving natural ecosystems," he said.
But, he added, efforts to increase the forested areas in northern regions may be ineffective in combating warming and can be a distraction from the real answer, which is the need to reform our system of energy production.
The result does "suggest it's more important to preserve and restore tropical forests that had been previously recognized," he added.
Tropical forests help cool the planet in two ways, Caldeira pointed out -- by absorbing carbon dioxide and by drawing up soil moisture which is released into the air forming clouds.