Larry Smith is an associate professor of geography at the University of California, Los Angeles, who studies the vast peatlands in Siberia. He said scientists are just now beginning to understand the role peatlands play in the regulation of greenhouse gases.
Healthy peatlands absorb carbon dioxide as new vegetation grows, serving as a carbon sink. But microbes that thrive in these oxygen-poor, soggy environments slowly and incompletely decompose the plant material, causing peat to accumulate over time.
"A primary product of anaerobic [oxygen-poor] decomposition by microbes is methane," Smith said. "As [the peat] is decomposed, some carbon is released as methane rather than carbon dioxide."
Calculations on how much carbon peatlands store show that most of the world's peatlands are "slight sinks to neutral in terms of their net carbon balance," Smith said.
He and his colleagues are now trying to tease out the details of where the balance for Siberian peatlands teetersfrom being a slight carbon sink or neutral to a source of carbon. Preliminary calculations suggest peatland could become carbon generators if global temperatures continue to rise, drying out the peatlands.
According to Rieley and his colleagues, the balance has already swung in Indonesia. Historically, tropical peat bogs have absorbed carbon at much faster rates than the peatlands in more northern latitudes.
"They are obviously of great importance in the global carbon cycle," Rieley said. "This role is now being destroyed by inappropriate land use and fire that has changed tropical peat bogs from sinks into sources of carbon."
Mega Rice Project
For decades Indonesia's peatlands have been burned and drained to make room for agriculture and settlements, but in 1995 the pace of destruction quickened with former dictator Suharto's Mega Rice Project.
The project was intended to turn Central Kalimantan into the country's rice bowl by logging and draining approximately 2.5 million acres (1 million hectares) of peatland and planting it with rice.
For two years workers cleared the forests and dug some 2,900 miles (4,600 kilometers) of canals, some as wide as 100 feet (30 meters). The canals were to keep the soil drained in the rainy season and crops irrigated in the dry season.
But the plan backfired. The peatlands are raised above the adjacent rivers, so the constructed canals only sucked the peatlands dry. Then in 1997 the El Niño weather phenomenon brought a severe, eight-month drought to the region. The high and dry peatlands went up in flames.
Rieley set out to measure the carbon released by the fires. He was joined by colleagues Florian Siegert of the Ludwig-Maximilians-University in Munich, Germany, and Susan Page of the University of Leicester in the United Kingdom. The team used a combination of satellite imagery and ground measurements to estimate that the 1997 peat and forest fires released between 0.87 and 2.57 billion tons of carbon into the atmosphere.
"Undoubtedly these fires and associated carbon loss from degrading peat converted to agriculture and settlement are contributors to the accelerating increase in atmospheric CO2 concentrations," Rieley said.
The team's original report appeared in the science journal Nature in 2002. In today's issue (November 11, 2004) of the journal, a news feature investigates the current crisis and the conservation community's attempts to bring the peatlands back to life.
At a press conference on Wednesday, Rieley and colleagues called on political leaders and international aid organizations for support in their efforts to save the Indonesian peatlands.
John Roach is a freelance journalist based in Ketchum, Idaho.
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