From New Scientist
© Copyright New Scientist, RBI Limited 1999
December 25, 1999
Peter Hadfield, Tokyo
THE MASSIVE forest fires in Indonesia are accelerating global warming by increasing ozone levels in the lower troposphere, according to a study by Japan's Meteorological Agency.
THE MASSIVE forest fires in Indonesia are accelerating global warming by increasing ozone levels in the lower troposphere, according to a study by Japan's Meteorological Agency.
Since 1993, the agency's research institute at Tsukuba, east of Tokyo, has been sampling and measuring greenhouse gases generated by the massive fires using collectors on Japan Airlines planes flying from Tokyo to Sydney. Between autumn of 1997 and spring 1998, during the height of the burning season, researchers found that the maximum concentration of carbon monoxide jumped to 380 parts per billion--ten times the normal level.
Hidekazu Matsueda, who headed the research team, says carbon monoxide is a typical by-product of smouldering forest fires. Carbon monoxide is especially dangerous because it produces ozone through a complicated photochemical reaction. "Many reactive gases are produced from slow burning," says
Matsueda. "Their reactions in the atmosphere are very complicated." Ozone in the lower troposphere is a very potent global warming gas.
The Japan Airlines planes collected their samples while travelling at altitudes of between 8000 and 13 000
metres. The planes also sampled several other greenhouse gases, including carbon dioxide and methane. While there were increases in many of these gases during the Indonesian burning season, Matsueda says the jump in the level of carbon monoxide was the most significant. He warns that forest fires caused by slash-and-burn methods of agriculture contribute even more to global warming than had previously been believed.