How El Niño fueled the massive fires in Indonesia: 'Turned off the taps'

The 2026 fire season in Indonesia is further evidence of how human climate impacts interact with natural weather cycles and land degradation, says Friederike Otto, professor of climate science at Imperial College London in the UK.

Together with colleagues from the international research network World Weather Attribution (WWA), she presents the new report at a press conference.

The main message is that this autumn's catastrophic fires in large parts of Indonesia were greatly enhanced by global warming, which is mainly caused by man's use of fossil fuels.

According to the researchers' calculations, the temperature during the fire season was 1.6 degrees higher than it would have been without human climate change. At the same time, the weather phenomenon El Niño – which is particularly strong this year – led to a 50 percent reduction in rainfall in the affected area.

The combination created perfect conditions for the fires to grow in scope and spread unchecked to larger areas, the researchers write in the report.

- El Niño turned off the taps and the fossil emissions turned up the heat, says Friederike Otto.

The researchers also state that changing land use has played an important role. Large-scale deforestation and drainage of carbon-rich peatlands to make way for agriculture has made the landscape extremely flammable.

At the same time, this is something that can be taken into account in order to prevent future fires of this size, the researchers point out. By, for example, rewetting parts of the peatland, areas are created that can reduce the risk of large-scale spread.

This year's unusually extensive land and forest fires in Indonesia were at their strongest during the period August to the end of October. In total, approximately 1.9 million hectares were destroyed – an area almost twice as large as Scania.

The smoke spread across Southeast Asia and has worsened the air quality for roughly twelve million people in Indonesia, Singapore, Malaysia and East Timor.

The Indonesian Ministry of Health has reported over 400,000 cases of respiratory infections directly linked to the fires. Almost half of those affected are children under the age of nine, an age group whose lungs are particularly sensitive to inhaling particles. According to the researchers' calculations, it could lead to thousands of premature deaths.

In addition, valuable ecosystems and habitats for, for example, the country's endangered population of orangutans have been seriously damaged.

The researchers conclude that the risk of similar fires will increase during future El Niño periods unless the phase-out of fossil fuels is accelerated and the preventive protection of forests and peatlands is strengthened.