Huge swathes of land are closer to sea level across Southeast Asia than previously realised, highlighting the flood dangers faced by millions, according to a new study using advanced satellite imagery. In low-lying countries vulnerable to sea level rise and with land prone to sinking due to subsidence, like Indonesia, Thailand, Vietnam and the Philippines, it means more of the population will face annual extreme sea level events that are progressively getting worse due to climate change. Past coastal flood risk assessments and projections have been let down by a lack of accuracy in satellite radar data that measures land elevation levels. However, researchers from Dutch-based research institute Deltares were able to perform the first global elevation model using new satellite Light Detection and Ranging (LiDAR) data, providing a more accurate picture. As a result, in Indonesia, the land area below 2m detected by LiDAR is more than 14 times what was previously thought, compared to the more commonly used Shuttle Radar Topography Mission (SRTM) data. In Thailand, the amount is about five times SRTM estimates, and seven times in the Philippines.

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Channel News Asia