Future Flood Losses in Major Coastal Cities

This article, published in the journal Nature Climate Change, quantifies present and future flood losses in the world’s largest 136 coastal cities. The researchers conclude that the world’s coastal cities cannot afford to ignore adaptation measures and policies in the face of increasing climate-related flood losses.

Current aggregated average annual flood losses in the sample cities come in at approximately US$6 billion per year. To analyze future risk, the researchers utilized four main scenarios combining types of socio-economic and environmental change such as subsidence and sea-level rise. These projections indicate that these flood losses will climb to an estimated US$52 billion by 2050. Although existing adaptive and protective measures will maintain flood probability, they must be updated immediately to counter sea-level rise and subsidence. Maintaining today’s standard of flood probability is an insufficient strategy to reduce coastal flood risk. Although improving flood protection standards can decrease the number of floods, the magnitude of losses from the floods which still do occur will increase. In order to reduce risk, adaptation policy must reduce flood probability rather than maintain it at a constant level.

According to the report, although adaptation can be expensive, it is far less costly than aggregate damage losses sustained without adaptive measures. The researchers recommend that local, national, and international authorities prepare for larger floods by strengthening early warning and evacuation systems, instituting comprehensive insurance schemes, and improving post-disaster rebuilding capabilities.

The researchers also single out Miami, New York City, and New Orleans, stating that these three cities explain an astounding 31% of global aggregate losses from the 136 cities studied due to their low levels of protection and high wealth.



Publication Date: August 2013

Authors or Affiliated Users:

  • Stephane Hallegatte
  • Colin Green
  • Robert J. Nicholls
  • Jan Corfee-Morlot


Resource Category:

Resource Types:

  • Academic research paper
  • Climate science


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