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Vancouver named one of top cities at risk from sea-level rise

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A man walks along the Stanley Park seawall in Vancouver, one of the areas most vulnerable to sea-level rise.

Rising sea levels due to climate change are a major threat to coastal cities around the world, and according to a new study, Vancouver ranks near the top of the list of cities most at risk.

This study, which is part of an ongoing research project by the Organisation for Economic Co-operation and Development (OECD), specifically looks at the largest coastal cities around the world, with their existing coastal protections, and estimates the present and future global cost of flooding due to sea-level rise. Of the 136 cities from around the world included in the study, those most at risk include: Guangzhou (China), Miami (US), New York (US), New Orleans (US), Mumbai (India), Nagoya (Japan), Tampa-St. Petersburg (US), Boston (US), Shenzen (China), Osaka-Kobe (Japan), and Vancouver (Canada).

In 2005, the global cost of damages due to sea-level rise was estimated at roughly $6 billion per year. Continued updates to the project, estimating a sea-level rise of only between 20-40 centimetres, have shown that this cost could increase to $52 billion per year by the middle of this century, and possibly reach in excess of $1 trillion per year by the end of the century if nothing is done.

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According to the research, the main reason for these staggering costs is that current flood protection plans are based on what has happened in the past. With conditions changing due to global warming, and the resulting climate change (melting ice-caps), there is an urgent need for us to change the way we think and the way we make policy, to anticipate the events to come. Also, we need to even look at areas that are not considered vulnerable today, as conditions may elevate their risk in years to come.

In January, the B.C. government released a Sea Level Rise Adaptation Primer which stated the severe risk that Vancouver faces due to sea-level rise: "The Lower Mainland, consisting of Metro Vancouver and the lower Fraser River Valley, is very vulnerable to sea level rise because of a 127 kilometre system of dikes, which were not built with sea-level level rise factored into the design. This area also has very expensive real estate subject to flood risks."

Vancouver does have plans in place, though. In November of 2012, the city became the first in Canada to have a climate change adaptation strategy. The strategy, detailed in a 58-page document, deals with issues such as stormwater management, coastal flood risk assessment, flood-proofing policy and even developing policy for having back-up power in case of emergencies. The report notes that the minimum level of sea rise that OECD project used (20 cm) has already been reached over the past century, and that the rate of sea-level rise is increasing, having nearly doubled over the past 30 years or so.

"I think it's another strong message about why that work is so urgent, but I don't think there's any stronger message than the floods that we saw in Calgary this past year, and in Toronto," Vancouver City Councillor Andrea Reimer told CBC News.

"You might be able to argue with a report. It's very hard to argue with the weather, and the observed impacts of extreme weather."

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According to the researchers, the cost estimate for improving flood management and defenses in the 136 cities examined in the study is roughly $50 billion per year. That is, certainly, a lot of money. However, looking at this in the long term, once we get past the year 2050, the estimated cost of the damages caused by coastal flooding is set to quickly outstrip that amount. Given the potential losses if we do nothing, this seems like a very wise long-term investment.

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