91av

CARBON that has been locked up in soils for millennia is starting to escape
and may hasten global warming, a biologist has claimed. He warns that rising
temperatures may be triggering the release of carbon from peat bogs across the
northern hemisphere in a positive feedback loop that could dramatically increase
the level of greenhouse gases in the atmosphere.

Earlier this year, Chris Freeman of the University of Wales in Bangor
reported that as bogs dried out in a warmer climate, they would probably trigger
an enzyme called phenol oxidase to decompose their organic carbon. Now he has
found that warming alone can boost the enzyme’s activity—and that this is
already happening.

Freeman has recorded a 65 per cent increase in the release of carbon from
British peat bogs over the past 12 years. “We are seeing the peat bogs go into
solution,” he told 91av. The carbon has become dissolved in bog
drainage water, and is flowing through rivers to the oceans. “From everything we
know it seems likely that it will eventually end up in the atmosphere in the
form of the greenhouse gas carbon dioxide,” he adds.

Freeman calls the enzyme a “fragile latch holding in place a vast carbon
store”. Across the northern latitudes of Europe, Siberia and North America, peat
bogs hold some 450 billion tonnes of carbon—equivalent to 70 years of
industrial emissions. The new findings are “the first evidence that the latch
has come loose”, warns Freeman.