Boreal Peatlands are Not a Global Warming Ticking Time Bomb as the Climate Changes

First Posted: Jun 10, 2015 09:51 AM EDT

Many have pointed to peatlands as a ticking time bomb for global warming. Boreal peatlands have massive stores of carbon, which means that a rise in temperatures could cause them to release that carbon. However, researchers have now found that peatlands actually aren't as dangerous as expected.

In this latest study, the researchers used biochemical composition of a peat core collected from the James Bay Lowland in Canada in order to assess the historical relationship between climate and the extent of peat decomposition The core is a record of peat accumulation over the last 7,500 years and contains two intervals when temperatures were about two degrees Celsius warmer than normal, providing a natural analogue for modern warming.

Peat formed during these warm intervals was not extensively decomposed compared to peat formed during cooler periods. Instead, the most extensive decomposition coincided with drier conditions and longer oxygen exposure time during peat formation. This means that oxygen exposure is the primary control on peat decomposition.

"It is too early to declare peatlands and their massive carbon stocks are secure," said Ron Benner, one of the researchers, in a news release. "Changing precipitation patterns could cause drier conditions, increasing oxygen exposure time and promoting decomposition. Thawing permafrost in arctic peatlands could also trigger loss of previously inaccessible carbon. In addition, increasing atmospheric nitrogen pollution can allow rapidly decomposing vascular plants to outcompete the more recalcitrant Sphagnum (peat moss). However, the results of the study indicate the direct effect of increasing temperatures on decomposition will be relatively minor."

The findings are published in the journal Global Biogeochemical Cycles.

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TagsClimate Change, global warming, Carbon Dioxide, Peat, Carbon Storage