Simon Challis, Reuters 4 Dec 07;
Even being optimistic that flood protection levels will be high everywhere in the future, the large population and asset exposure is likely to translate into regular city-scale disasters across the globe.
LONDON (Reuters) - As many as 150 million people in the world's big coastal cities are likely to be at risk from flooding by the 2070s, more than three times as many as now, according to a report released on Tuesday.
Climate change, population growth and urban development will mean the number at risk will rise from the current 40 million while total property and infrastructure exposure is forecast to rise to $35 trillion -- 9 percent of projected global GDP.
The report from the Organization for Economic Co-operation and Development, put together by disaster modeling firm Risk Management Solutions and leading scientists, is the first part of the largest ever study on urban coastal flood exposure.
The report analyzed the vulnerability now and in the future of 130 port cities to a major flood, on a scale likely to occur once in 100 years.
Miami in Florida will remain the city with the highest value of property and infrastructure assets exposed to coastal flooding caused by storm surge and damage from high winds, the report said.
The city has exposed assets of $400 billion today. Those are projected to rise in value to over $3.5 trillion by 2070.
But with rapid economic development in Asia, Guangzhou in China will be the second most exposed city in terms of assets in 2070, followed by New York, Kolkata, Shanghai, Mumbai, Tianjin, Tokyo, Hong Kong and Bangkok, the report said.
GROWTH AND GROWING RISK
Population growth and urban development in coastal cities will increase the exposure, exacerbated by the effects of climate change and subsidence, the report said.
Scientists believe global warming will cause sea levels to rise and bring more frequent and severe storms and other natural disasters.
"This report raises crucial policy considerations, and highlights the urgency for climate change mitigation and risk-informed adaptation strategies at a city level," said Jan Corfee-Morlot, the OECD's senior policy advisor on climate change.
Policies to mitigate climate change will bring "precious time" for exposed cities to implement strategies to adapt to and protect themselves from the higher risk of flooding, said Corfee-Morlot.
Projects to protect cities from flooding, such as the Thames Barrier built to protect central London from a major flood, typically take up to 30 years, said the report.
Policymakers from around the world are meeting this week in Bali to try to hammer out a successor agreement to the Kyoto Protocol to cut man-made emissions of carbon dioxide that are believed to lead to global warming.
Insurers, who end up paying a large part of the bill from any damage caused by climate change, should encourage policyholders to adopt methods to adapt to effects of global warming, the report said.
(Editing by Matthew Tostevin)
City-scale flooding disasters predicted by 2070
Paul Eccleston, Telegraph 4 Dec 07;
Millions more people across the world are going to be at risk from flooding in the future because of climate change and population increases.
And as many as 150m people in the world's major cities - more than three times the 40m currently - will have to rely on flood defences for protection by 2070, according to a major new study.
But even then city-scale disasters are likely to become regular events across the world.
The gloomy forecasts come from the first stage of the largest study on urban coastal flood exposure ever undertaken.
More than 130 key port cities worldwide were analysed to investigate the likely impact of climate change alongside subsidence, population growth, and urban economic development.
The study focused on the exposure of people and property and infrastructure to a 1-in-100 year flood event now and in the future. The cities most exposed to coastal flooding today and in the future were ranked into a league table.
London was ranked 41 in a list for population exposed in 2070 and 27th for property and infrastructure assets exposed.
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The study found nine of the 10 cities with the highest population at risk will be in Asia. Calcutta was ranked highest, with 14m people exposed by the 2070s.
Property and infrastructure at risk worth $3 trillion today, 5 per cent of current global GDP, will become $35 trillion by the 2070s - 9 per cent of the projected global GDP.
Miami will have the highest exposure with assets worth $3.5 trillion at risk followed by Guangzhou in China, with $3.3 trillion and New York, with $2.1 trillion.
The study was carried out by the Organisation for Economic and Co-operation Development (OECD) and jointly prepared by Risk Management Solutions (RMS) and academics representing the University of Southampton, the Tyndall Centre, Météo-France and the Centre International de Recherche sur l'Environnement et le Développement (CIRED).
The study revealed that around half of the total population exposed to coastal flooding caused by storm surge and damage from high winds is contained in just 10 cities split between developed and developing countries with Mumbai (Bombay) being the most threatened by coastal flood.
The risk will increase as the century progresses particularly in the developing countries and by 2070 nine of the 10 cities most at risk will be in Asia.
Calcutta will be the most vulnerable, with the exposed population expected to increase over seven times to more than 14m million people, largely driven by rapid population growth in the city.
Over the coming decades, the unprecedented growth and development of the Asian mega-cities will be a key factor in driving the increase in coastal flood risk globally. In terms of population exposure, Calcutta will be closely followed by Mumbai, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai, Bangkok and Rangoon. Miami is in ninth place and would be the only top 10 city situated in a currently developed country, while Hai Phong (Vietnam) is ranked tenth.
The cities with the highest value of property and infrastructure assets exposed to coastal flooding today are primarily in developed countries.
The top ten cities, which contain 60 per cent of the total exposure, are from only three wealthy countries, America, Japan, and The Netherlands, with Miami ranked top.
But the rapid economic expansion expected in developing nations means that in future the highest exposure will become more concentrated in Asian cities, with eight of the top 10 in this region. Guangzhou is the second most exposed city in terms of assets, followed by New York, Kolkata, Shanghai, Mumbai, Tianjin (China), Tokyo, Hong Kong, and Bangkok.
Dr Celine Herweijer, principal scientist of future climate at RMS, said: "Population growth and development are clearly key drivers of the increase in exposure, particularly in Asia, but climate change and subsidence acutely magnify the problem.
"These findings deliver a clear message to businesses that invest, or are planning to invest, in highly exposed cities to start implementing pro-active risk management strategies that consider how risks will evolve over time,"
"For the insurance industry, there is both an opportunity and a necessity to promote adaptation. Crucially, rising hazard does not have to translate into increased risk if the right measures are taken."
Prof Robert Nicholls, IPCC author and director of research at the University of Southampton, said: "The concentration of flood exposure in rapidly developing cities urgently underscores the need to integrate climate change implications into both national coastal flood risk management and urban development strategies.
"Given the aggregation of people and assets in port cities and their importance to global trade, failure to develop effective adaptation strategies would inevitably have not just local, but international economic consequences."
Stéphane Hallegatte, economist at Météo-France and CIRED, said: "Even being optimistic that flood protection levels will be high everywhere in the future, the large population and asset exposure is likely to translate into regular city-scale disasters across the globe.
"Adaptation strategies need to be underpinned by solid governance, to help key cities understand and proactively manage current and future flood risk."
Asia's delta cities top flooding risk list
Straits Times 5 Dec 07;
Out of 10 cities expected to be most exposed to massive storm floods in 2070, nine are in Asia
PARIS - ASIA'S massive delta cities have the most to fear from catastrophic storm floods driven by climate change, according to a report published here yesterday.
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, the Organisation for Economic Cooperation and Development (OECD) said in the report.
Publication of the report coincided with the 11-day United Nations conference in Bali, Indonesia, aimed at shaping a long-term response to the climate peril.
Today, about 40 million people around the world are exposed to coastal flooding in large port cities, according to the report.
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 was US$3 trillion (S$4.3 trillion) - or around 5 per cent of the global gross domestic product (GDP) in 2005, it said.
Miami, Greater New York, New Orleans, Osaka-Kobe, Tokyo, Amsterdam, Rotterdam, Nagoya, and Tampa-St Petersburg and Virginia Beach, in the US states of Florida and Virginia respectively, are the most valuable pieces of real estate at risk.
'Climate change is already happening, and concerted action is needed now to prevent its worst impacts,' OECD secretary-general Angel Gurria said at the meeting in Bali, which started on Monday and will run until Dec 14.
'A range of economic policy options is available, and political commitment is needed to implement them,' he said.
The report was authored by OECD experts working with scientists from Britain's University of Southampton, US company Risk Management Solutions and France's Meteo-France and Centre for International Climate and Environmental Research.
They estimated that by the 2070s, the total population exposed could more than triple, to around 150 million people.
Of the 'Top 10' coastal cities expected to be most exposed in 2070, nine are in Asia.
The total value of assets exposed by the 136 cities in the 2070s was put at US$35 trillion, or 9 per cent of projected global annual GDP.
Ranked according to assets exposed to flooding, the 2070 list is headed by Miami, Guangzhou, Greater New York, Kolkata, Shanghai, Mumbai, Tianjin (China), Tokyo, Hong Kong and Bangkok.
The assessment projected 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 raise sea levels and likely make storms more powerful.
In its estimate, the OECD assumed that sea levels would rise 0.5m as a result of thermal expansion 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 said sea levels would climb between 18cm and 59cm by 2100.
But in a summary of the overall report, issued in Valencia, Spain, last month, it said it could no longer put an upper limit on this projection because of uncertainties about ice sheet loss.
The OECD report did not factor in the effectiveness of flood defences in its calculations, saying that exposure to a flood 'does not necessarily translate into impact'.
AGENCE FRANCE-PRESSE
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