Flood damage to cost up to $1 trillion per year by 2050

Flood damages for the globe’s 136 largest coastal cities could cost $1 trillion annually by 2050 if protective measures aren’t put in place.

In 2005, annual flood losses for the coastal cities came to $6 billion. A team of economists and scientists considered the impacts of factors such as sea level rise and economic and population growth, noting that floods will become increasingly costly. So even if cities beef up protective measures such as dikes and levees, total flood damage will cost $60 billion to $63 billion by 2050, the authors report August 18 in Nature Climate Change.

Five U.S. urban areas — Miami, New York-Newark, New Orleans, Tampa-St. Petersburg, and Boston — rank among the 20 cities with highest projected flood losses in 2050. At nearly $12 billion annually, Guangzhou, China ranks the highest. Most of the cities in the top 20 are in low-lying river deltas.

The team, led by economist Stéphane Hallegatte at the World Bank in Washington, D.C., recommends ambitious protective measures and disaster relief planning.