A recent study has revealed that rapid climatic changes, combined with increasing population, economic growth and land subsidence, could cause global flood losses worth 52 billion dollars by 2050.
''Future Flood Losses in Major Coastal Cities'' is part of an ongoing project by the Organisation for Economic Co-operation and Development (OECD) to explore the policy implications of flood risks due to climate change and economic development.
Average global flood losses in 2005 that was estimated at about US 6 billion dollars per year could see more than nine-fold increase in the global risk of floods in large port cities between now and 2050 with projected socio-economic change, the researchers said.
The cities that were ranked most ''at risk'' today among those of 136, as measured by annual average losses due to floods, includes: Guangzhou, Miami, New York, New Orleans, Mumbai, Nagoya, Tampa-St. Petersburg, Boston, Shenzen, Osaka-Kobe, and Vancouver.
The United States and China were among the countries at greatest risk from coastal city flooding, the study added.
Miami, New York City and New Orleans are the three American cities that were held responsible for 31 per cent of the losses across the 136 cities due to their high wealth and low protection level.
Adding Guangzhou, the four top cities explained 43 per cent of global losses as of 2005.
The study has also found out that because flood defences have been designed for past conditions, even a moderate rise in sea-level would lead to soaring losses in the absence of adaptation.
Meanwhile, coastal cities will have to improve their flood management, including better defences, at a cost estimated around US 50 billion dollars per year for the 136 cities.
According to Dr Stephane Hallegatte, from the World Bank and lead author of the study, ‘There is a limit to what can be achieved with hard protection. Populations and assets will remain vulnerable to defence failures or to exceptional events that exceed the protection design.’
Hence, policy makers should consider early warning systems, evacuation planning, more resilient infrastructure and financial support to rebuild economies and help cities deal with disasters, when they do hit.