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- Permanent Link:
- http://dpanther.fiu.edu/dpService/dpPurlService/purl/FI15061848/00001
Notes
- Summary:
- This global screening study makes a first estimate of the exposure of the world’s large port cities to coastal flooding due to storm surge and damage due to high winds. This study also investigates how climate change is likely to impact each port city’s exposure to coastal flooding by the 2070s, alongside subsidence and population growth and urbanisation. The assessment provides a much more comprehensive analysis than earlier studies, focussing on the 136 port cities around the world that have more than one million inhabitants.
Most of these largest port cities are found in Asia (38%), and many of them (27%) are located in deltaic settings, again mainly in Asia. Cities in deltaic locations tend to have higher coastal flood risk as a result of their tendency to be at lower elevations and experience significant (natural and anthropogenic) subsidence.
The analysis focuses on the exposure of population and assets1 to a 1 in 100 year surge-induced flood event (assuming no defences), rather than the ‘risk’ of coastal flooding. This is, firstly, because knowledge about flood protection across the spectrum of cites is limited and can give misleading results for risk analysis. Secondly, flood protection does not eliminate risk as protection measures can fail and it is important to consider the implications of this residual risk. Exposure is a particularly useful metric for this type of comparative study. The potential for protection to influence risk is considered briefly based on known examples and relative wealth as an indicator of protection standard. Hence, global, continental and national results on exposure are provided, as well as the city rankings which indicate those cities most worthy of further more detailed investigation.
The analysis demonstrates that a large number of people are already exposed to coastal flooding in large port cities. Across all cities, about 40 million people (0.6% of the global population or roughly 1 in 10 of the total port city population in the cities considered here) are exposed to a 1 in 100 year coastal flood event. The exposure is concentrated in a few of the cities: the ten cities with highest population exposure contain roughly half the total exposure and the top 30 cities about 80 percent of the global exposure. Of these thirty cities, nineteen are located in deltas. For present-day conditions (2005) the top ten cities in terms of exposed population are estimated to be Mumbai, Guangzhou, Shanghai, Miami, Ho Chi Minh City, Kolkata, Greater New York, Osaka-Kobe, Alexandria and New Orleans.2
The ten cities with highest population exposure today are almost equally split between developed and developing countries. When assets are considered, the current distribution becomes more heavily weighted towards developed countries, as the wealth of the cities becomes important. The total value of assets exposed in 2005 is estimated to be US$3,000 billion; corresponding to around 5% of global GDP in 2005 (both measured in international USD). The top 10 cities in this ranking are Miami, Greater New York, New Orleans, Osaka-Kobe, Tokyo, Amsterdam, Rotterdam, Nagoya, Tampa-St Petersburg and Virginia Beach. These cities contain 60% of the total exposure, but are from only three (wealthy) countries: USA, Japan and the Netherlands.
By the 2070s, total population exposed could grow more than threefold to around 150 million people due to the combined effects of climate change (sea-level rise and increased storminess), subsidence, population growth and urbanisation. The total asset exposure could grow even more dramatically, reaching US $35,000 billion by the 2070s; more than ten times current levels and rising to roughly 9% of projected annual GDP in this period. ( English )
Record Information
- Source Institution:
- Florida International University
- Rights Management:
- Please contact the owning institution for licensing and permissions. It is the user's responsibility to ensure use does not violate any third party rights.
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