DMF paper: Southeast Asia team explores SRM impact on rainfall

borneo indonesia palm oil
Palm oil plantations in East Kalimantan, Indonesia – Copernicus Sentinel-2 (2019) Credit: ESA, CC BY-SA 3.0 IGO.

A DMF-funded team in Indonesia with members from across Southeast Asia – including Malaysia and Vietnam – have published new research on the impacts of solar radiation modification (SRM) on floods and droughts in the region.

The paper’s lead author is Prof. Mou Leong Tan, from Universiti Sains Malaysia, who started working on SRM after meeting Dr Heri Kuwanto (a DMF principal investigator) at a Degrees workshop in Bali in 2019. Professor Tan, is a researcher for the Indonesia team and is also now leading his own separate DMF team in Malaysia, the first ever SRM research project in the country.

The new paper sheds light on how SRM might affect weather extremes in the Kelantan River Basin. Modelling shows that climate change will likely cause more frequent and intense floods there, especially under the RCP 8.5 high-emission scenario. However, no research had previously been conducted to assess how SRM could influence that risk.

The findings suggest that if SRM were deployed to maintain global temperatures at 2020 levels under an extreme scenario of global warming, it could reduce the amount of intense precipitation under a high emission scenario, but could also reduce precipitation in the driest months. The paper found “decreases of monthly precipitation under SRM could be useful in reducing the flood risk but may also make the water shortage problem worse.”

The paper suggests this study should be repeated in other tropical river basins, as well as in Southeast Asia, so that a fair comparison can be made to better understand the impact of SRM. It also said: “additional SRM research on the water supply and agricultural sectors, i.e., oil palm and paddy are needed in the future, since different crops have different responses to the changes in precipitation and temperature.”


Impacts of Solar Radiation Management on Hydro-Climatic Extremes in Southeast Asia – Water, M. L. Tan, L. Juneng, H. Kuswanto, H. Xuan Do, and F. Zhang