Growing exposure

December 7, 2007

An interesting report came out earlier this week ranking the world’s coastal cities in terms of their exposure to flood risk now and in the future.

The report, part of an Organization for Economic Cooperation and Development project on cities and climate change, listed Miami, New York, New Orleans, Osaka-Kobe, Tokyo, Amsterdam, Rotterdam, Nagoya, Tampa-St. Petersburg and Virginia Beach as the top 10 cities in terms of assets exposed to coastal flooding and damage from storm surge and high winds.

Interestingly, the top 10 cities come from only three countries:  the United States, Japan and the Netherlands. Together, though, they represent 60% of the $3 trillion in assets exposed to loss in the 136 port cities around the world with more than one million inhabitants examined in the study.

The ranking is somewhat different in terms of people exposed to coastal flooding in large port cities, with a top 10 of Mumbai, Guangzhou, Shanghai, Miami, Ho Chi Minh City, Kolkata (formerly Calcutta), New York, Osaka-Kobe, Alexandria and New Orleans. Across all the cities examined, approximately 40 million people are exposed to a one in 100 year coastal flood event, according to the report with the top 10 cities containing roughly half the exposure.

By 2070, that exposure could grow to 150 million people due to a combination of events including climate change, population growth and increased urbanization. Meanwhile, the growth in total assets exposed to coastal flooding in the port cities is even more dramatic, to $35 trillion by the 2070s, the OECD study says.

The top 10 cities in terms of exposures are projected somewhat differently for the 2070s. In terms of population, all the top 10 exposed port cities will be in Asia but for Miami, according to the OECD study, which ranked them as Kolkata, Mumbai, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai, Bangkok, Rangoon, Miami and Hai Phong.

In terms of assets exposed in 2070, the ranking is Miami, Guangzhou, New York-Newark, Kolkata, Shanghai, Mumbai, Tianjin, Tokyo, Hong Kong and Bangkok.