New estimates from Climate Central estimate that 340 million to 480 million people would be affected by flooding in coastal areas due to sea level rise, a threefold increase up from previous estimates. The study used CoastalDEM, a digital elevation model developed from NASA’s Shuttle Radar Topography Mission (SRTM) which uses neural networks to reduce vertical error. This has resulted in a more accurate modeling of sea level rise related flooding along coastal areas by reducing the overestimation in elevation for coastal areas. The algorithm was able to factor in trees, bridges, and buildings in order to recalculate land elevations. In previous elevation models, the presence of trees and buildings caused an oversestimation of elevations which meant that sea level flooding would affect less of a land area. To calculate the estimate affected population. the researchers used 2100 population predictions to calculate how many people might be affected by climate change driven sea level rise along coastal areas.
Kulp, S. A., & Strauss, B. H. (2019). New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding. Nature communications, 10(1), 1-12. doi:10.1038/s41467-019-12808-z