Most estimates of global mean sea-level rise this century fall below 2m. 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 190M 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 630M people live on land below projected annual flood levels for 2100, and up to 340M for mid-century, versus roughly 250M at present. We estimate one billion people now occupy land less than 10m above current high tide lines,
including 230M below 1m.
Climate Central, Palmer Square #402, Princeton, NJ, 08542, USA
Copyright: https://doi.org/10.1038/s41467-019-12808-z. © The Author(s) 2019