Published: 5th November 2009
The WORLD’s peat bogs store twice as much carbon as forests.
But under threat from global warming, bogs could collapse and release billion of tonnes of carbon into the atmosphere.
Writing in the influential journal Science on November 6, Nancy Dise, Professor of Environmental Science at MMU, explains that while direct threats from man – such as draining, clearing for agriculture, or mining, - are understood, the effect on peatlands of global warming are unpredictable but potentially as damaging.
"Over the time span of centuries, peatlands exert a net cooling effect on the global radiation balance, because of the effect of removing long-lived atmospheric carbon dioxide," she explained.
20 years of pollution
"However, should peatlands begin to degrade on a large scale, this stored carbon could be released, reducing - or even reversing - their climate cooling effect."
In the UK, bogs store the carbon equivalent of about 20 years' worth of national industrial carbon dioxide emissions.
Research shows that as an ecosystem, bogs are relatively hardy in the face of temporary crises such as floods and droughts, but permanent changes in climate will affect these areas in complex ways, and predicting their net effect “will not be possible by simply attempting to combine individual impacts”.
"Long-term global change — particularly warming, drought, and elevated nitrogen deposition — may ultimately induce shifts in some peat-forming areas to new ecosystems such as grassland or shrubland," adds Dise.
New system of monitoring
"While the increase in biomass from plants could in part compensate for carbon losses, the gains are short-lived, and the key peatland quality of slowly removing and storing carbon for hundreds or thousands of years is lost."
Professor Dise and her team are leading a new multinational project to safeguard peatland resources in the face of climate change.
The European Research Association Biodiversa project, PEATBOG: Pollution, Precipitation, and Temperature Impacts on Peatland Biodiversity and Biogeochemistry, is a €1.8 million study which involves seven partners from five countries.
Its aim is to understand how the biodiversity and ecosystem functioning of peatlands across Europe are impacted by nitrogen pollution and climate change, and to develop indicators of risk to these impacts.
Added Professor Dise: "These are unique and valuable ecosystems and the challenge is to forecast both the future environmental conditions that peatlands will experience and the internal feedbacks and state changes that may be triggered by these conditions."
Find the full paper at www.sciencemag.org Science Vol. 326 6 November 2009
Dise, N.B. 2009. Peatland response to global change. Science 326: 810-811.
MMU information about the PEATBOG project: