WASHINGTON (AFP) - Peat bogs in tropical forests, long key outlets for greenhouse gases, could dry up due to farming and global warming, further accelerating climate change and putting more pressure on wetlands, a study has found.
The vast swamplands, located largely in south-east Asia, have long helped store atmospheric carbon dioxide (CO2) and put a brake on global warming.
The forested peat bogs have been under increasing threat in recent years from clear-cutting and drainage for palm-oil plantations, according to a report released in the US Proceedings of the National Academy of Sciences (PNAS) on Monday.
That has helped fuel climate change, which is now altering precipitation patterns that in turn could make the wetlands dry up even faster, said Charles Harvey, a professor at the Massachusetts Institute of Technology (MIT) and one of the authors of the report.
As a result, the former carbon sinks could become net emitters of CO2 and accelerate the process that they once slowed.
"There is a tremendous amount of peatland in Southeast Asia, but almost all of it has been deforested," said Harvey, a professor of civil and environmental engineering.
Once they have been deforested and drained, the peat lands dry out, and the organic material they contain oxydizes, returning the carbon dioxide to the atmosphere.
Sometimes they can also catch fire and burn for long periods of time, creating vast smoke clouds that aggravate pollution.
The tropical peat lands "may contain as much carbon as the amount consumed in nearly a decade of global fossil fuel use, and raging peat fires in Indonesia alone have been estimated in some years to contribute 10 to 40 percent as much greenhouse gas to the atmosphere as all the world's fossil fuel burning," the scientists said.
While peat lands in temperate climate zones are generally covered in moss, tropical peat lands are generally covered by trees that can grow to as much as 45 meters. Fires can destroy vast swathes of these forests.
Harvey's study focused on one of the last perfectly preserved peat bogs in the world, located in Brunei where the peat is still growing, in large part because the oil-rich nation has resisted the lure of the palm-oil market.
"It is remarkable how much the peat forests are just gone everywhere else," the study said.
By studying the pristine peat bogs, the scientists hope to discover how the forests actually accumulate peat and work to preserve surviving areas or even regenerate the forests on damaged lands.