Smoke from the burning of forests decreases rainfall, according to new research to be published this month in Geophysical Research Letters. Scientists studied the area of Kalimantan, Indonesia, last year when the southeastern portion of the island was engulfed in smoke and the northwestern portion was relatively smoke-free, and found that precipitation was much lower in the clouds in the smoke-contaminated area. Haze from the burning of forests has also caused serious health problems in southeast Asia in recent years. Earlier studies have shown that urban air pollution can have a similar effect to forest fires in repressing rainfall.