Benjamin H. Strauss, Robert E. Kopp, William V. Sweet, Klaus Bittermann

Climate Central

Published date February 23, 2016

Unnatural Coastal Floods: Sea level rise and the human fingerprint on U.S. floods since 1950

  • States the link between sea level rise and increased nuisance floods, with local water level exceedance thresholds defined by the National Weather Service based on historically observed minor impacts, is straightforward and well established
  • Isolates and analyses the effect of human-caused sea level rise on flooding
  • Finds that across the 27 study gauges, only 33% (16-60%) of observed flood days since 1950 would still have exceeded local nuisance flood thresholds after deducting the human contribution to global sea level rise from water level records
  • Finds the number and fraction of flood days linkable to anthropogenic global sea level rise have climbed steadily by decade, from about 45% (11-69%) near the beginning of the study period (1955- 1964), to about 76% (56-89%) at its end (2005-2014)
  • Finds that for the most recent decade, it is extremely likely – there is a greater than 95% probability – that more than half of observed flood days would not have occurred without the human contribution to global sea level