Hurricane Sandy was an historic storm, especially for low-lying New York City. Its impact serves as a wake up call to cities around the world near water.

In Asia, many cities are growing rapidly along coastal regions. As the waters rise, how well will these megacities take a blow from a superstorm? AFP reports:

“These cities are undergoing very rapid expansion and they are not only exposed to sea-level rise, they are also exposed to tropical cyclones,” said Bob Ward, director of policy at the Grantham Research Institute on Climate Change and the Environment in London.

“It is clear there isn’t any urban planning going on, and they have a lot of poor people living in very low-quality housing who are going to be especially vulnerable and exposed.”

That’s not good news for a large number of highly populated coastal cities. In 2007, OECD came up with a list of the cities most at risk from coastal flooding by 2070. Of the top 20, 15 of those cities are in Asia. The top five including Calcutta, Mumbai, Dhaka, Guangzhou, Ho Chi Minh City. Others on the list are Shanghai, Bangkok, Tokyo, and Jakarta. Many of these cities have populations that rival New York City.

Superstorms don’t give much warning. Around the world, it’s time to start preparing.