Underground Peat Fires Push Toxic Haze Into Malaysia, Threaten Orangutans

Indonesia's 2026 fire season is accelerating as a strengthening El Niño dries out the country's peatlands, satellite images from NASA's Aqua satellite showed on September 1. Unlike ordinary forest fires, peat fires smolder underground at low temperatures once drought lets flames penetrate the normally wet peat deposits of Kalimantan, Sumatra and Papua. "Surface fires are less of a concern, but when fires get underground, they just won't stop," said Mark Cochrane, an ecologist at the University of Maryland Center for Environmental Science who has studied Indonesia's peat fires for nearly a decade. Indonesia holds about 36% of the world's tropical peatlands, which makes it especially vulnerable to this kind of fire.

The benchmark year is 2015, Indonesia's worst fire season in decades, when three months of burning released 1.75 billion tons of greenhouse gas equivalents, more than Japan emits in a year. By September 2, roughly a month into this year's fires, Indonesia had already released about 10% of that 2015 total, said Robert Field, a Columbia University researcher who built the Global Fire Weather Database. Indonesia's meteorological agency found about 90% of the country received little or no rain in early August.

The smoke has already crossed into Malaysia. Sarawak's Serian district on Borneo declared a state of emergency on Friday after air-quality readings hit 512 on Malaysia's Air Pollutant Index, far past the 300 level classified as hazardous. The declaration closed 647 schools in a district of about 154,000 people. Rain believed to be from cloud-seeding brought brief relief, dropping readings to 219, though the state of emergency remained in place.

The fires have also pushed Indonesia's wildlife into danger. Rescuers evacuated nine orangutans from wildfire-threatened habitat in West Kalimantan's Ketapang district in less than a month, including a mother and baby moved this week by the wildlife foundation Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI). One orangutan rescued earlier died of smoke exposure, a necropsy found. YIARI veterinarian Komara said prolonged smoke exposure can affect an orangutan's respiratory system, adding that the surviving mother and baby would continue to be monitored at the rescue center.