Friday, 26 December 2014

Peat fires and carbon loss

Together with co-authors in Canada, US, UK and Netherlands, we have just published a progress article in Nature Geoscience  (vol 8, 2014) on the carbon losses from peat fires: Global vulnerability of peatlands to fire and carbon loss.

Ssmouldering combustion of dry peat.Available at Imaggeo.
In the paper we review how fire is a threat to the naturally stored carbon in peatlands and has the potential to drastically disturb the carbon stocks. While dry peat is a very flammable substance because it is a porous and carbon-rich, the amount of carbon stored in peatlands exceeds that stored in vegetation globally. Peat fires are dominated by smouldering combustion, which is ignited more readily than flaming combustion but is more difficult to suppress. In fact smouldering fires can persist deeper and in much wetter conditions than flaming fires. In very wet or flooded peatlands, most of the carbon stock typically is protected from smouldering, and resistance to fire has led to a build-up of peat carbon storage in boreal and tropical regions over long timescales. But drying as a result of climate and human activity (eg, drainage) lowers the water table and increases the frequency, depth and extent of peat fires. The combustion of deep peat affects older soil carbon that has not been part of the carbon cycle for centuries to millennia, and thus dictates how fire emissions affect the carbon cycle and feedbacks to the climate.