1. Home
  2. Asia
  3. Indonesia

Indonesia tries “cloud seeding” to prevent flooding in Jakarta

Artificial rain unit, Indonesia, during cloud seeding exercise
(Ministry of Research and Technology)

Scientists in Indonesia are experimenting with cloud seeding, or firing salt-based chemicals into clouds to force out rain, to try and prevent flooding in the capital Jakarta, home to increasingly destructive rains.

On 27 January, aircraft began dropping salt onto rain clouds to induce rain over the Java Sea before the clouds could reach the mega-capital of more than 10 million people. The operation, which cost US$1.3 million, ended on 28 February.

“We have yet to conduct a full evaluation, but in general we have seen a significant reduction in rainfall in Jakarta,” Heru Widodo, head of the Artificial Rain Unit at the Agency for Assessment and Application of Technology under the Ministry of Research and Technology, told IRIN.

“People seem to have forgotten about floods already,” he said, referring to January flooding in Jakarta that brought parts of the city to a near standstill, killing an estimated 20 people and displacing another 40,000.

Cloud seeding has been carried out in West Africa to boost rainfall in the drought-prone edge of the Sahara desert.  And while it has been used regularly in Indonesia to fight forest fires that frequently spread in Sumatra and Borneo during the dry months from May-October, this was the first time the technique has been to prevent flooding.

After Jakarta, Widodo’s team is turning to Central Java Province, where heavy rains have caused a dam to overflow in Bojonegoro District and cold `lahar’ (rainwater mixed with volcanic rock and sand) from the still-active Mount Merapi volcano to slam into residential areas, destroying homes and bridges.

A series of eruptions on Mt Merapi killed more than 300 people and displaced hundreds of thousands in 2010.

The team will conduct cloud seeding in Bojonegoro and the region of Yogyakarta (also on Java Island and home of Mt Merapi) until the end of March.

“Volcanic eruptions [in 2010] left 80 million cubic metres of mud and sand, and when it rains these materials can wreak havoc [in] neighbourhoods,” Widodo said. In the latest mudflow incident, one person was killed when volcanic debris swept away vehicles in a Yogyakarta village last month, local media reported.

“Our plan is to reduce the intensity of rains that fall in these areas,” he said.
Widodo said cloud seeding, though not a mainstream strategy, may be able to mitigate the effects of increasingly erratic weather the country has seen.

The National Disaster Management Agency said floods, rain-triggered landslides, cyclones and forest fires killed nearly 300 people and displaced more than 700,000 in 2012.

A dissenting voice

Thomas Djamaluddin, head of the Centre for Atmospheric Sciences at the National Aviation and Aerospace Agency, discounts seeding as a tool to control weather. “An analysis of the dynamics and growth of [seeded] clouds showed that the favourable weather was only accidental,” he said. “Satellite images showed that movements of clouds never threatened Jakarta during [February].”

He said cloud seeding operations only affected clouds at the height of 12,000-15,000 feet (3.6-4.5km), which did not contain much rain anyway.

“Cumulonimbus clouds that are as high as 10km are too difficult and too risky to reach,” he said. “For a large area like Jakarta where floodwaters also come from other areas, don’t ever think of relying on weather modification technology to prevent flooding.”

Mahally Kudsy, an official at the Centre for Weather Modification Technology, said salts dropped from 3.6km can reach clouds at greater heights because they strengthen the upward current of moist air.

Whether or not cloud seeding proves capable of diverting rain, it can only be part of the solution, said Syamsul Maarif, head of the government’s National Disaster Management Agency.

“Cloud seeding is only a supplementary method in our flood prevention efforts. Maintaining the drainage system, dredging rivers and strengthening dams and dykes should be the main priority.”


This article was produced by IRIN News while it was part of the United Nations Office for the Coordination of Humanitarian Affairs. Please send queries on copyright or liability to the UN. For more information: https://shop.un.org/rights-permissions

Share this article
Join the discussion

Hundreds of thousands of readers trust The New Humanitarian each month for quality journalism that contributes to more effective, accountable, and inclusive ways to improve the lives of people affected by crises.

Our award-winning stories inform policymakers and humanitarians, demand accountability and transparency from those meant to help people in need, and provide a platform for conversation and discussion with and among affected and marginalised people.

We’re able to continue doing this thanks to the support of our donors and readers like you who believe in the power of independent journalism. These contributions help keep our journalism free and accessible to all.

Show your support as we build the future of news media by becoming a member of The New Humanitarian. 

Become a member of The New Humanitarian

Support our journalism and become more involved in our community. Help us deliver informative, accessible, independent journalism that you can trust and provides accountability to the millions of people affected by crises worldwide.