New Orleans, Miami, New York and China's Guangzhou will be the four coastal cities hit hardest by flood damage over the next 37 years, according to a study conducted through the Organisation for Economic Co-operation and Development and published in the journal Nature Climate Change. Worldwide, damages to major coastal cities will reach $1 trillion by 2050, of which those four cities -- due to location and lack of adequate preparation -- will shoulder over 40 percent of the burden.

The rise in annual costs, from $6 billion in 2005 to a projected $52 billion by mid-century, is attributed to rising sea levels and extreme weather. Yes, coastal cities are inherently at risk from this sort of thing, but global warming increases the odds quite a bit. Population and economic growth also help to explain how the study's authors arrived at such large numbers: As cities grow, they'll have more to lose.

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Also vulnerable are Mumbai, Nagoya, Tampa-St. Petersburg, Boston, Shenzen, Osaka-Kobe and Vancouver, according to the study. Guangzhou, China; Guayaquil, Ecuador; Ho Chi Minh City, Vietnam; and Abidjan, Ivory Coast, are at risk of losing the highest percentage of their overall wealth.

We hear climate scientists bemoaning the lack of data on global warming's specific impact. Well, a ranked list of expected damages is about as specific as it gets. There's going to be loss no matter what, say the researchers, but getting a head start on "early warning systems, evacuation planning, more resilient infrastructure and financial support to rebuild economies" could end up being highly cost-effective, not to mention lifesaving.