BARCELONA - Scientists pointed the finger on Wednesday at Southeast Asian countries for draining wetlands for palm oil and cheap timber production, warning the practice was stoking dangerous global warming.
In a presentation on the sidelines of the UN climate talks, a network of scientists branded Southeast Asia the world leader in greenhouse gases that seep from degraded peat soils.
Peatlands comprise compacted carbon from vegetation, deposited over thousands of years.
The carbon is safely stored when the soil is covered with water, but starts to be released as a greenhouse gas when the land is exposed to air, explained Hans Joosten of Germany's Greifswald University, who coordinated the study.
"They become very big sources of carbon dioxide and nitrous oxide," Joosten said.
"The main hotspot is Southeast Asia, with a lot (of emissions) from deforestation and fire and from palm oil and pulpwood plantations," he told a press conference.
Globally, 1.3 billion tonnes of CO2 were emitted from drained peatlands in 2008, compared with 1.06 billion tonnes in 1990, Joosten told a press conference.
This figure comprises only biological degradation of peatlands and does not include peatland burning, which by some estimates could add at least two billion tonnes of CO2 per year, according to the report.
To give a comparison, total greenhouse-gas emissions in 2004 were the equivalent of around 49 billion tonnes of CO2, according to the UN's Intergovernmental Panel on Climate Change (IPCC).
Of the 1.3 billion tonnes in emissions from peatlands last year, 580 million tonnes came from Southeast Asia, led by Indonesia, Malaysia and Papua New Guinea.
The region's emissions from this source have increased by 250 percent since 1990 and now account for 70 percent of the regional pollution from oil, gas and coal -- the "fossil fuels" that are most notoriously to blame for man-made climate change.
China, too, is a major source of peatland warming, ranked third in the world after Indonesia and Russia.
The study is the first inventory of global peatlands, said Susanna Tol of Wetlands International, which commissioned the probe.
It was released as negotiators wrangled over a draft text that will be put to the December 7-18 UN climate talks in Copenhagen. Its goal is a treaty that will reduce man-made carbon emissions and help poor countries in the firing line of climate change.
Tol said peatlands had been badly overlooked in international talks, where a more favoured focus has been on preventing carbon emissions by preserving forests and curbing deforestation.
But peatlands store three times the amount of carbon in all the world's forests, which makes it imperative to conserve them, she said.
Joosten said peatlands were found in 175 countries. They account for only three percent of the world's land area, but store a massive 550 billion tonnes of carbon because they are so compact, with some layers being up to 20 metres (65 feet) thick.
So long as drained peatlands are exposed to air, the carbon is released, which means that the sole option is to "re-wet" them by returning them to bog or marsh, he said.
Numerous small-scale projects are underway in various countries to "re-wet" peatland that has been drained and abandoned, some of which entails planting reeds or trees that can then be harvested.
"It entails making a change from dry agriculture to wet agriculture," said Joosten, adding though that the cost of restoration was hard to estimate.
"It is very strongly dependent on the local situation."