In just a few months, burning that took place in 1997 in Indonesia released 2.6 billion tons of carbon-comparable to the amount that the entire planet's biosphere takes up in a year-mostly in the form of carbon dioxide, the main greenhouse gas responsible for climate change. Researcher Susan Page from the University of Leicester, United Kingdom, and her colleagues discovered this alarming fact in 2002 after they analyzed satellite imagery and ground measurements from the Indonesian forest fires, which burned right down into the peaty soil. It was exposure of this vast source of carbon to the fire, rather than the trees themselves, that caused most of the gaseous re- lease. These findings clearly show that wildfires not only directly affect people's health and property, but they also contribute to global warming.

The immediate consequence of burning is the release of smoke into the atmosphere. Smoke contains...