A new study by NASA researchers has determined that seasonal wildfires can double the amount of carbon dioxide (CO2) released from the Earth to the atmosphere above many regions in Asia.
In the last decade, Asian farmers have cleared tens of thousands of square miles of forests to accommodate the world's growing demand for palm oil, an increasingly popular food ingredient. Ancient peatlands have been drained and lush tropical forests have been cut down.
As a result, the landscape of equatorial Asia now lies vulnerable to fires, which are growing more frequent and having a serious impact on the air as well as the land.
A team of NASA-sponsored researchers have used satellites to make the first series of estimates of CO2 emitted from these fires - both wildfires and fires started by people - in Malaysia, Indonesia, Borneo, and Papua New Guinea.
They are now working to understand how climate influences the spread and intensity of the fires.
Using data from a carbon-detecting NASA satellite and computer models, the researchers found that seasonal fires from 2000 to 2006 doubled the amount of CO2 released from the Earth to the atmosphere above the region.
The scientists also observed through satellite remote sensing that fires in regional peatlands and forests burned longer and emitted ten times more carbon when rainfall declined by one third the normal amount.
Tropical Asian fires first grabbed the attention of government officials, media, and conservationists in 1997, when fires set to clear land for palm oil and rice plantations burned out of control.
The fires turned wild and spread to dry, flammable peatlands during one of the region's driest seasons on record.
By the time the flames subsided in early 1998, emissions from the fires had reached 40 percent of the global carbon emissions for the period.
Until recently, scientists knew little about what drives changes in how fires spread and how long they burn.
"In this region, decision makers are facing a dichotomy of demands, as expanding commercial crop production is competing with efforts to ease the environmental impact of fires," said Jim Collatz, an Earth scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of the study.
"The science is telling us that we need strategies to reduce the occurrence of deforestation fires and peatlands wildfires.
Without some new strategies, emissions from the region could rise substantially in a drier, warmer future," he added.