New study triples global estimates of population threatened by sea level rise

October 29, 2019

Climate Central research finds hundreds of millions more people than previously known live on land at risk from coastal flooding linked to climate change; largest vulnerable populations concentrated in Asia

By 2050 sea level rise will push average annual coastal floods higher than land now home to 300 million people, according to a Climate Central study published in Nature Communications. And high tide lines could permanently rise above land occupied by some 150 million, including 30 million in China. Without augmented or new coastal defenses, populations in these areas may face regular flooding or permanent inundation within 30 years.

These findings are based on CoastalDEM, a new digital elevation model developed by Climate Central. Researchers used machine learning methods to correct for systematic errors in the principal elevation dataset used until now for international assessment of coastal flood risks, NASA’s Shuttle Radar Topography Mission (SRTM). CoastalDEM-derived estimates of the global population at risk are three times greater than values produced using SRTM elevation data.

CoastalDEM is not the most accurate source of elevation data for the U.S. Climate Central has previously published more accurate risk zone maps for U.S. coastal locations based on publicly accessible, lidar-derived elevation data.

The published study as well as a research brief from Climate Central detail findings from individual assessments of 135 countries across multiple climate scenarios and years. Climate Central also used its new elevation data to produce interactive maps, enabling neighborhood-level exploration of threatened areas around the world.

Report: Web Version and PDF