Global warming may hasten carbon release from worlds peat bogs

November 7th, 2008 - 1:54 pm ICT by ANI  

Washington, Nov 7 (ANI): A new analysis has determined that billions of tons of carbon sequestered in the worlds peat bogs could be released into the atmosphere in the coming decades as a result of global warming.

The analysis of the interplay between peat bogs, water tables, and climate change, was done by scientists at Harvard University, Worcester State College, and the Japan Agency for Marine-Earth Science and Technology.

Typically found at northerly latitudes, peat bogs are swampy areas whose cold, wet environment preserves organic matter, preventing it from decaying.

This new work shows how peat bogs stability could be upset by the warming of the earth, which has disproportionately affected the higher latitudes where the bogs are generally found.

According to the scientists, an atmospheric release of even a small percentage of the carbon locked away in the worlds peat bogs would dwarf emissions of manmade carbon.

Our modeling suggests that higher temperatures could cause water tables to drop substantially, causing more peat to dry and decompose, said Paul R. Moorcroft, professor of organismic and evolutionary biology in Harvards Faculty of Arts and Sciences.

Over several centuries, some 40 percent of carbon could be lost from shallow peat bogs, while the losses could total as much as 86 percent in deep bogs, he added.

Each square meter of a peat bog contains anywhere from a few to many hundreds of kilograms of undecomposed organic matter, for a total of 200 to 450 billion metric tons of carbon sequestered in peat bogs worldwide.

This figure is equivalent to up to 65 years worth of the worlds current carbon emissions from fossil fuel burning.

Peat bogs contain vast stores of carbon, Moorcroft said. They will likely respond to the expected warming in this century by losing large amounts of carbon during dry periods, he added.

Moorcroft and his colleagues simulated the responses of two peat bogs in northern Manitoba to temperature increases of 4 degrees Celsius, or 7.2 degrees Fahrenheit, a gain that is at the conservative end of estimates for the next 100 years.

Their modeling looked specifically at water table dynamics, since peat bogs stability is grounded in their cold, waterlogged nature.

Previous modeling has assumed that decomposition in peat bogs is like that in a conventional soil, Moorcroft said.

Ours is the first simulation to take a realistic look at the interaction between the dynamics of the water table, peat temperatures, and peat accumulation, he added. (ANI)

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