Peat bog gases 'accelerate global warming'

Global warming is set to dramatically worsen because of huge amounts of carbon dioxide (CO ₂) being released from the world's peatlands, a study has found.

Global warming is set to dramatically worsen because of huge amounts of carbon dioxide (CO ₂) being released from the world's peatlands, a study has found.

Scientists analysing the huge stores of natural CO ₂ locked up in peatlands have found they are being released into the environment at an accelerating rate. At the current rate, the CO ₂ released from peatlands will exceed those produced by the burning of fossil fuel as early as 2060.

If no action is taken and the peatland emission of greenhouse gases continues, the scientists estimate there will be no peatlands left by the end of the century and that levels of CO ₂ in the atmosphere would have doubled as a result.

The scientists also believe man-made pollution is behind the sudden and unexpected release of CO ₂ from the world's major peatbogs, which extend from North America to Siberia.

In a series of seminal experiments published today in the journal Nature, the researchers found that the increase in atmospheric CO ₂ seen in recent decades can have a direct impact on destabilising the carbon locked up in peat bogs.

The research is the first direct evidence of a "positive feedback" between CO ₂ in the atmosphere and the huge stores of carbon locked up on land, with increases in one causing a corresponding increase in the other.

Chris Freeman of the University of Wales in Bangor, who led the research team, said that a third of the carbon stored on land is locked up in peat and its sudden release into the atmosphere is a major concern.

"We've got an enormous carbon store locked up in peatbogs which is equivalent to the entire store of carbon in the atmosphere and yet this store on land appears to have sprung a leak," Dr Freeman said.

The amount of CO ₂ being released from peatlands is accelerating at a rate of 6 per cent per year. "By 2060 we could see more CO ₂ being released into the atmosphere than is being released by burning fossil fuel," he said.

In the past, scientists have suggested that increasing temperatures due to global warming or decreasing rainfall is resulting in more carbon being released from peatlands but the latest experiments suggest that increasing atmospheric CO ₂ is itself the cause.

Tests on peat samples taken from three different sites in Britain show that increasing the amount of CO ₂ in the air around the samples causes the peat itself to emit up to 10 times the amount of carbon it would under normal conditions.

Dr Freeman said peatbogs release carbon in a dissolved organic form. Emissions from peatlands into surrounding rivers and streams has increased by between 65 and 90 per cent over the past six years.

"The rate of acceleration suggests that we have disturbed something critical that controls the stability of the carbon cycle on our planet," he said. Dissolved organic carbon in rivers and water courses can react with the chlorine in water-treatment processes to produce potentially carcinogenic chemicals, Dr Freeman said.

"We've known for some time that CO ₂ levels have been rising and that these could cause global warming. But this new research has enormous implications because it shows that even without global warming, rising CO ₂ can damage our environment," he added.