University of Leicester eBulletin

No Heat Without Fire

October 2002
No 244


How wildfires contribute to global warming


An international group of scientists led by Leicester researcher Dr Susan Page has highlighted how forest fires contribute significantly to global warming through the release of greenhouse gases.

Their research, published this week in the internationally renowned scientific journal Nature, presents new insights into the effects of tropical forest and peatland fires on global climate

Dr Susan Page, of the Department of Geography, University of Leicester, and a team of European and Indonesian scientists, used a combination of satellite-based earth observation and intensive field data collection to estimate the amount of the greenhouse gas CO2 released by fires in the forested and deforested peatlands of Indonesia.

The retrospective study evaluated the impact of the 1997/1998 El Niño driven fire disaster.  During that time, fires destroyed huge areas of rainforest and peat soils in south-east Asia, especially in Indonesia.

Dr Page said: “It was the biggest fire catastrophe ever observed in that region. A noxious, yellow cloud of haze extending 3000 x 5000 kilometres covered the region for several months, affecting Indonesia, and neighbouring countries of Singapore, Malaysia, Brunei and Thailand.  The economic damage resulting from the smoke alone was estimated to exceed two billion dollars, closing airports, closing down schools and offices and disrupting trade. The polluting ‘haze’ also had a serious impact on human health by increasing respiratory problems, especially amongst the young and elderly.”

For their studies, the scientists focused on tropical peat swamp forest, a largely unknown ecosystem that occurs on deep organic deposits that can exceed 12 metres.

Owing to the high carbon content of these organic soils, surface fires spread underground into the peat layer.  These fires are characterised by incomplete burning and produce huge amounts of smoke and fine-particled ‘haze’.  Peat swamp forests represent approximately 40 per cent of the land area in Indonesia that burned during the 1997/1998 fires.  The amount of carbon released into the atmosphere during that time is the biggest ever measured and, at 0.81-2.57 Billion tonnes, corresponds to 13 to 40 percent of the annual global production by burning fossil fuels, such as oil, coal and gas.

Dr Page said: “Our work highlights the fact that tropical peatlands store huge amounts of carbon that will continue to be released to the atmosphere as CO2 during future forest fires and land conversion from forest to agriculture.  Carbon dioxide is known to be responsible for the global warming of the atmosphere of the earth.  Recurrent fires have, therefore, the threatening potential of making a very significant contribution to this warming, particularly during El Niño weather events, which lead to extended drought conditions throughout South-east Asia and the Pacific region.”

Dr Page added: “The data presented in Nature are as relevant as ever because the forests in Indonesia have again been burning during this year’s extended dry season, caused by a weak El Niño weather event.  Most fires are started for land clearance purposes, but during El Niño years they rapidly spread out of control, consuming both vegetation and underlying peat. The combination of drought with poor land management practices, in particular excessive logging and drainage of the peat swamps, have made this ecosystem very susceptible to fire.

“Unless land use policies are changed to control land clearance by fire, then recurrent fires will lead to a complete loss of Indonesia’s peat swamp forests and continued, high emissions of CO2 to the atmosphere.”

The scientists are demanding intensive national and international efforts to avoid further fires in the tropical peat swamp forests and the promotion of environmentally sustainable management of this sensitive ecosystem. 

“We are asking politicians to act now,” said Dr Page.

NOTE TO NEWSDESK: Further information and contacts:
Dr Susan Page , Department of Geography , University of Leicester , Telephone 0116 252 3318 OR 0116 252 5245 , email

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