Drying of northern wetlands has led to much more severe peatland wildfires and nine times as much carbon released into the atmosphere, according to new research led by a University of Guelph professor.
The study, published today in Nature Communications, is the first to investigate the effect of drainage on carbon accumulation in northern peatlands and the vulnerability of that carbon to burning.
"Russia, Indonesia and Canada all have abundant peatlands, but they also have been hotspots for intense peat fires in the past decade," said Guelph professor Merritt Turetsky, who worked on the study with William Donahue of the Water Matters Society of Alberta and Brian Benscoter from Florida Atlantic University.
In pristine states, peatlands often resist fire because of their wet soils. "Our study shows that when disturbance lowers the water table, that resistance disappears and peat becomes very flammable and vulnerable to deep burning," she said.
Recently, destructive peat fires plagued the Moscow region. In the late 1990s, severe Indonesian fires in drained peatlands released carbon equivalent to 40 per cent of annual global fossil fuel emissions.
"Our results demonstrate the importance of cumulative impacts," Turetsky said.
Peatlands store vast amounts of carbon by pulling carbon dioxide out of the atmosphere. For millennia, they've accumulated plant debris the remains of wood, moss, and other plants and locked it up in layers of saturated peat more than five metres deep in places.
Northern peat covers large swaths of the landscape. Because about half of that peat consists of carbon, it is a globally important carbon pool.
But peatlands are also carbon sources, as this same debris fuels wildfires. "While fire is a widely recognized disturbance in upland forests, the impacts of fire on peatlands and their carbon storage have been largely overlooked," said Benscoter.
The majority of the world's peatlands are
|Contact: Prof. Merritt Turetsky, University of Guelph|
University of Guelph