Peat Bogs Can Play Role in Warming

Temperature increases could destabilize carbon-rich northern peat bogs, resulting in a massive release of carbon and the acceleration of global warming trends, according to a recent Harvard study.

The research disputes a long-standing belief that peat bogs in the northern latitudes were fairly immune to temperature increases because of consistent precipitation patterns in those regions.

The findings—published in this month’s issue of the journal Nature Geoscience—showed that modest rises in temperature dry out the bogs regardless of precipitation patterns, said Paul R. Moorcroft, an associate professor of biology and co-author of the study.

“There has been the assumption that since precipitation hasn’t changed, the peat lands will be fine,” Moorcroft said.

Peat bogs—pools of dead plant material that does not decay due to the cold, wet environment—facilitate a build-up of undecomposed carbon.

The process generates more peat, a positive-feedback cycle that makes peat bogs huge carbon sinks, according to the study.

But the carbon is also a looming threat to atmospheric stability.

The researchers’ analysis of peat bogs in northern Manitoba found that a temperature increase of four degrees Celsius—a conservative estimate of future warming—would release 40 percent of stored carbon in shallow peat bogs and up to 86 percent of carbon in deeper bogs, further contributing to the buildup of greenhouse gases.

Peat bogs contain 30 to 60 times the amount of carbon emitted annually worldwide, and their destabilization threatens to dramatically accelerate the global warming process, Moorcroft said.

“This study further points in the direction that the price of inaction will be increasingly high,” said Professor of Forestry N. Michelle Holbrook.

And the carbon depletion raises the specter of other devastation as well.

The study found that temperature increases cause the water table in the peat bogs to drop, leaving a dry layer of peat exposed.

The dry layer of peat, an extremely combustible material, provides ready fuel for ravaging wildfires. These fires could drive carbon emissions higher still, Moorcroft said.

Indonesian peatland fires in 1997 resulted in the release of 80 to 250 billion tons of carbon into the atmosphere, according to a study of those fires in the journal Nature.

Moorcroft said he hopes to study further the potential for fires in northern bogs affected by climate change, particularly because this study predicted that carbon decomposition would soon rise rapidly, further emphasizing the importance of immediate action in mitigating global warming.

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