New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding

Most estimates of global mean sea-level rise this century fall below 2 m. This quantity is comparable to the positive vertical bias of the principle digital elevation model (DEM) used to assess global and national population exposures to extreme coastal water levels, NASA's SRTM. CoastalDEM is a new DEM utilizing neural networks to reduce SRTM error. Here we show - employing CoastalDEM-that 190 M people (150-250 M, 90% CI) currently occupy global land below projected high tide lines for 2100 under low carbon emissions, up from 110 M today, for a median increase of 80 M. These figures triple SRTM-based values. Under high emissions, CoastalDEM indicates up to 630 M people live on land below projected annual…

• NS
  National Science Foundation

  Award: 1663807
• NA
  National Aeronautics and Space Administration

  Award: 80NSSC17K0698
• VK
  V. Kann Rasmussen Foundation
• SF
  Schmidt Family Foundation
• NS
  Nuclear Safety and Security Commission