Asia’s massive delta cities have most to fear from catastrophic storm floods driven by climate change.
   According to an OECD report, of 136 port cities assessed around the world for their exposure to once-in-a-century coastal flooding, 38 per cent are in Asia and 27 per cent are located in deltas. Today, around 40 million people around the world are exposed to coastal flooding in large port cities. The top 10 cities most at risk, in terms of exposed population, are Mumbai, Guangzhou, Shanghai, Miami, Ho Chi Minh City, Kolkata, Greater New York, Osaka-Kobe, Alexandria and New Orleans. The total value of assets exposed in the 136 port cities analysed is 3,000 billion (three trillion) dollars or around five per cent of the global gross domestic product (GDP) in 2005.
   Miami, Greater New York, New Orleans, Osaka-Kobe, Tokyo, Amsterdam, Rotterdam, Nagoya, Tampa-St. Petersburg (Florida) and Virginia Beach (Virginia) are the most valuable pieces of real estate at risk.
   By the year 2070s, the total population exposed could more than triple, to around 150 million people. Of the Top 10 most exposed coastal cities in 2070, nine are in Asia. The 10 are: Kolkata, Mumbai, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai, Bangkok, Rangoon, Miami and Haiphong (Vietnam). The total value of assets exposed by the 136 cities in the 2070s is put at 35 trillion dollars, or nine per cent of projected global annual GDP.
   Their assessment projects the damage that would be caused by an extreme but very rare weather event — a combination of storm surge and high winds that, in purely statistical terms, occurs once a century.
   The exposure rises in the 2070s because of coastal subsidence and further population growth in these port cities, and the risk increases due to climate change, which will boost sea levels and is likely to make storms more powerful.
   In its estimate, the OECD assumes that sea levels will rise 0.5 metres (19.7 inches), as a result of thermal expansion (when water warms, it expands) as well as from melting ice sheets.
   In the first volume of a triple report on global warming, published in February, the UN’s Intergovernmental Panel on Climate Change (IPCC) said sea levels would climb between 18 and 59 centimetres (7.2 and 23.2 inches) by 2100.
   While industrialised countries are largely to blame for global warming, least developed nations suffer most. Scientists have warned that damage to the Earth’s weather systems this century will doom poor countries to worse hunger, water stress and damage from violent storms, droughts and floods. According to Oxfam, current levels of aid to poor nations for climate change were an insult, with 50 billion dollars per year needed.
   ‘We believe the rich and the most polluting countries should pay the vast share of that money,’ said Oxfam campaigner Charlotte Sterrett.
   Tarequl Islam Munna
   Dhaka