Fire season: Year-round, with heightened risk between February and September
Damage report: Ever since the massive wildfire in Indonesia between 1982 and 1983, one of the 20th century's largest, forest fires have been a sadly familiar event in the country. The regions of Kalimantan (the Indonesian portion of the island of Borneo) and Sumatra are particularly afflicted. A severe wildfire season in 1986 drew complaints about air quality and economic damage from neighboring Malaysia and Singapore, but it wasn't until fierce forest fires from September 1997 to April 1998made dramatically worse by the El Niño effect, an ocean-atmosphere phenomenon that causes drier conditions in this regionthat Indonesia truly became a regional outcast. Countries as distant as Australia, the Philippines, and Sri Lanka protested about the resulting gray "haze" and loss of air quality. In the worst-affected areas of Indonesia, simply breathing became equivalent to smoking 80 packs of cigarettes a day. Since fire is used as a cheap land-clearing tool to make way for cash crops, forest fires in Indonesia are almost invariably human-induced. But given that 10 million hectares of land burned in the 1997-1998 fires, it's clear these controlled burns can quickly get out of control.
Future trends: Worrisome. Last year's forest fires in Indonesia were the worst since 2006, but the fact that Indonesia's fires are primarily caused by humans and not by environmental factors offers some hope. Indonesian law forbids forest burning; the only question is whether Indonesia's leaders can summon the political will to take on the arsonists.