remote sensing

The Amount of Carbon released from Peat and Forest Fires in Indonesia during 1997, Nature, Vol. 7th Nov. 2002

Press release

Professor Jack Rieley of the School of Geography, University of Nottingham, Dr. Susan Page of the Department of Geography, University of Leicester and Dr. Viktor Boehm of Kalteng Consultants announce a breakthrough article in the latest issue of the internationally renowned scientific journal Nature. Professor Rieley, Dr. Page and Dr. Boehm, together with a team of European and Indonesian scientists present new insights into the effects of tropical forest fires on global climate. The scientists used a combination of satellite-based earth observations 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.

This retrospective study evaluated the impact of the 1997/1998 El Niño driven fire disaster. During that time forest and peatland fires destroyed huge areas of rainforest in Southeast Asia, especially in Indonesia. 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 US dollars, closing airports, schools and offices and disrupting trade. The polluting ‘haze’ also had a serious impact on human health by increasing respiratory problems affecting, especially, the young and elderly.

For their studies, the scientists focused on tropical peat swamp forest, a largely unknown ecosystem that occurs on organic soil deposits that can exceed 12 metres in thickness. Owing to the high carbon content of this organic material, surface fires spread underground into the peat layer. These fires are characterised by incomplete burning and produce huge amounts of smoke, fine-particle ‘haze’ and chemical pollutants. 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 during that time was the biggest ever detected and, at 0.81-2.57 Billion tonnes, corresponds to 13 to 40 percent of the annual global carbon production by burning fossil fuels, such as oil, coal and gas.

The work by Professor Rieley, Dr. Page and Dr. Boehm and their colleagues highlights the fact that tropical peat stores huge amounts of carbon that will continue to be released to the atmosphere as carbon dioxide during future forest fires and land conversion from forest to agriculture. Carbon dioxide is known to play a major role in the global warming of the atmosphere of the earth. Recurrent fires have, therefore, the threatening potential of making a very significant contribution to climate change, particularly during El Niño weather events that, in Indonesia, lead to a reduction in precipitation and drought conditions during the extended dry season that results.

Professor Rieley, Dr. Page and Dr. Boehm said: “The data presented in Nature for what happened in the 1997 disaster are very relevant at the present time because the peatlands of Indonesia have been burning again with great ferocity, generating more choking haze, during this year’s extended dry season, caused by a weak El Niño. Once again these fires have been started by people for land clearance but also for sheer amusement and vandalism. The haze has been denser for longer periods than in 1997 and has had a worse effect upon human health. Palangka Raya airport was closed for almost two months and the economic and social life of Central Kalimantan Province came to a virtual standstill. Hospitals became full and many people left for elsewhere in Indonesia. The main source of the polluting haze are the fires inside the peat soil that smoulder for a long time after surface fires have extinguished and re-ignite in the slightest breeze causing further fires on the surface. The combination of drought and poor land management, in particular excessive logging and drainage of the peat swamps, have made this ecosystem very susceptible to fire, which will reoccur frequently in the future unless drastic mitigation measure are undertaken”.

Unless land use policies are changed to control land clearance by fire, then recurrent fires will lead to a complete loss of Borneo’s peat swamp forests within a few decades with continued, high emissions of carbon dioxide to the atmosphere. The scientists are demanding intensive national and international efforts to avoid further fires in the tropical peat swamp forests and to promote environmentally sustainable management of this sensitive ecosystem. They ask politicians and international aid donors to act now.