Indonesia Ramps Up Cloud Seeding to Fight Severe Wildfire Season

Indonesia is scaling up its use of cloud seeding — spraying silver iodide, salts or other particles into clouds to trigger rainfall — in an effort to fight a wildfire season that officials say is on track to be among the worst in years, driven by a strong El Niño. The Indonesian government says more than 100,000 hectares (247,000 acres) burned in the first half of the year; independent analysis by the deforestation monitoring site Nusantara Atlas put the figure through July at more than 285,000 hectares (704,000 acres) — more than four times the size of Jakarta.

Cloud seeding is rarely used to fight wildfires elsewhere in the world, but Indonesia has ramped up its use since being scarred by the 2015 fires, which burned through millions of hectares during a previous strong El Niño and created a regional haze crisis. According to the national weather agency BMKG, Indonesia carried out 252 cloud-seeding operations between 2021 and August this year, up from 85 in the preceding decade; most aimed to draw rain away from flooded areas, though many targeted wildfires or sought to wet flammable peatlands.

"Weather modification does not create clouds: we optimize clouds that have the potential to produce rain," said meteorologist Safillah Anggie Wahyuni, who has logged more than 300 flight hours on cloud-seeding missions in the three years since her first operation. "Weather modification will only be effective if the conditions are right," she added. Some experts are skeptical of the technique's use during the dry season, when wildfires peak. "Its effectiveness will be very low because of the lack of clouds," said I Putu Santikayasa, a hydroclimatology lecturer at IPB University.

BMKG's weather modification director, Budi Harsoyo, described cloud seeding as "a mitigation effort, not a permanent solution," citing his own research showing a 12-day cloud-seeding operation in 2023 doubled likely rainfall and eliminated fire hotspots. Indonesia's tropical peatlands are an important carbon store when wet but become highly flammable when dry, and fires there can smolder underground and reignite quickly; alongside cloud seeding, the country is also rewetting peatlands and monitoring fire hotspots by satellite and ground patrol.