Climate change made Indonesian fires more severe, scientists say

Wildfires that hit large parts of Indonesia ​from August to October and plunged ​much of Southeast Asia into hazardous smoke ‌were ​made much worse by "record-breaking" heat caused by human-induced climate change, scientists said on Friday.

While a very strong El Niño was the dominant factor ‌in determining the extremely low levels of rainfall across Indonesia from July, human-induced climate change contributed around 1.6 degrees Celsius of additional heat during the fire season, said a report by climate research group World Weather Attribution. "The conditions ‌that we saw this year would simply just not have happened in a world without the ‌human contribution to climate change, even with the very strong El Niño that we're seeing," said Theodore Keeping, a researcher into wildfires and extreme weather at Imperial College London who contributed to the report.

"You have multiple different drivers changing in different ways, but ⁠what we ​can say with very ⁠high confidence is that the driving weather conditions of these fires are getting more severe," he told a briefing. Pramudhian Firdaus, a ⁠wildfire researcher at Melbourne University, said September 2026 was Indonesia's fifth-driest September since 1991, with rainfall below normal levels ​across 84% of the country.

Decades of land-use change, involving extensive deforestation and the draining of flammable peatland ⁠to make way for industry and agriculture, also compounded this year's fire outbreaks. "Indonesian landscapes have changed dramatically over the last 30 years, ⁠with ​extensive peatland drainage and deforestation creating a landscape that is extremely vulnerable to ignition," Firdaus said.

According to data released on Thursday by the independent geo-monitoring platform Nusantara Atlas, almost 2.88 million hectares of Indonesian ⁠territory was affected by fire from January to October 2026, rising nearly 1 million hectares in October alone. The amount ⁠of fire-damaged land ⁠in the first three quarters of this year was 35% higher than in the same period of 2019, the last year Indonesia faced strong "super-El Nino" conditions, Nusantara ‌Atlas said.