| The changing risk profile of key coastal cities around the world
Over 130 key port cities worldwide were analyzed to investigate the likely impact of climate change alongside subsidence, population growth, and urban economic development. The study focuses on the exposure of people, property, and infrastructure to a 1-in-100 year flood event now and in the future, and could have significant public policy implications for where to focus adaptation strategies to climate extremes. Key findings include: * Population exposed to coastal flooding in large cities is likely to increase more than threefold to 150 million by the 2070s due to climate change, subsidence, and urban development. * Total property and infrastructure exposure is predicted to increase from US$3 trillion today – 5 percent of current global GDP - to US$35 trillion in the 2070s – 9 percent of the projected global GDP. * Miami is projected to have the highest property and infrastructure exposure by the 2070s, with more than US$3.5 trillion of exposed assets, followed by Guangzhou in China, with US$3.3 trillion and New York, with US$2.1 trillion. * Findings highlight the opportunity and a necessity for the insurance industry to promote climate change adaptation measures. Property and infrastructure exposure The cities with the highest value of property and infrastructure assets exposed to coastal flooding caused by storm surge and damage from high winds today are primarily in developed countries. The top ten cities, which contain 60 percent of the total exposure, are from only three wealthy countries (US, Japan, and the Netherlands), with Miami ranked as top. Miami remains at the top of the 2070 rankings, with exposed assets rising from approximately US$400 billion today to over US$3.5 trillion. However, the rapid economic development expected in the nations under development means that in the future the highest exposure becomes more concentrated in Asian cities, with eight of the top ten situated 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, respectively. “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,” said Dr. Celine Herweijer, principal scientist of future climate at RMS. “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.” Population exposure The study shows that around half of the total population exposure to coastal flooding caused by storm surge and damage from high winds is contained in just ten cities. Today, the ten most exposed cities are fairly evenly split between developed and developing countries, with Mumbai having the highest exposure to coastal flood. Looking ahead to the 2070s, exposure rises most rapidly in developing countries, with nine of the top ten cities in Asia. Kolkata (Calcutta) is most vulnerable, with the exposed population expected to increase over seven times to more than 14 million people, largely driven by the rapid population growth of 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, Kolkata is closely followed by Mumbai, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai, Bangkok, and Rangoon (Myanmar). Miami is in ninth place and would be the only top ten city situated in a currently developed country, while Hai Phong (Vietnam) is ranked tenth. “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,” said Prof. Robert Nicholls, IPCC author and director of research at the University of Southampton. “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.” The annual probability of a 1-in-100 year event affecting one major city globally is as high as 74 percent and almost 100 percent over five years. “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,” said Stéphane Hallegatte, economist at Météo-France and CIRED. “Adaptation strategies need to be underpinned by solid governance, to help key cities understand and proactively manage current and future flood risk.” “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, senior policy advisor on climate change at the OECD. “Mitigation will slow and limit the exacerbating effects of climate change on coastal flood risk, at a minimum bringing precious time for cities to implement adaptation measures.” The study report, ‘Ranking of the World's Cities Most Exposed to Coastal Flooding Today and in the Future,’ is part of a series planned by the OECD on the theme of Cities and Climate Change. Further work will look at the effectiveness of flood defence measures and the vulnerability of key cities globally. On December 10, Dr. Herweijer will present the results of the study at the United Nations Framework Convention on Climate Change. Read the executive summary (PDF).
•Date: 7th Dec 2007• Region: Various •Type: Article •Topic: BC general
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