Hurricane Katrina showed the vulnerability of the Louisiana city on the Gulf of Mexico.
2 Venice: By 2032 the Italian city is predicted to sink by 3.2in, which could be devastating.
3 Bangkok: The Thai capital suffered massive floods in 2011 and the tropical seas are rising steadily.
4 Shanghai: The Chinese city at the mouth of the Yangtze River is vulnerable.
5 Miami: Probably the most threatened US city due to porous bedrock beneath it.
6 Amsterdam: Sea defences are in place to keep many Dutch cities safe.
7 Dhaka: Bangladesh suffers massive flooding every year, threatening to displace millions of people.
8 New York: The Hudson River Valley may experience waters rising by 12 to 13in by 2080.
10 Cancun: The popular Mexican resort could disappear unless sea defences are put in place.