Rising sea levels due to climate change threaten to drown most of Richmond, Delta and New Westminster, but government officials and the real estate market appear to be guided by obsolete data.
Rising ocean levels will threaten low-lying areas by the end of the century, acknowledges the B.C. government. The only question is exactly how much and how fast sea levels will rise.
Latest authoritative research suggests B.C. officials may be underestimating the coming deluge.
The most recent reports by the British Columbia Ministry of Water, Land and Air Protection, one published in 2002 and another this year, conclude that B.C. should expect a mean rise in sea level anywhere between nine cm and 88 cm by 2100. Moreover, weather events such as storms cause temporarily high sea levels, currently at an average of about 20 cm above the norm. The report suggests the frequency of "storm surges" and resulting spikes in sea level will increase over the next century.
An 88 cm rise in sea level would place Vancouver International Airport mostly under water, and elevated storm surge levels would easily breach existing dykes around Richmond, flooding the delta in a matter of a few hours.
As sea level rises, vulnerable coastlines will be exposed to increased erosion. Coastal erosion in areas such as Tsawwassen, Point Grey and North Vancouver would seriously threaten coastal properties, and industries ranging from shipping companies to industrial chemicals would be forced either to build expensive walls or relocate.
And yet this scenario may no longer be grim enough to be accurate, according to a study published in Science magazine this March.
Paleoclimatologists Jonathan Overpeck of the University of Arizona and Bette Otto-Bliesner of the National Center for Atmospheric Research in Boulder, Colorado studied the effects of a variety of factors on the global mass of ice sheets. They forecast an accelerating surge in ocean levels.
The researchers factored in natural forces, such as the tilt of Earth's axis and the intensity of solar radiation, as well as human-caused factors such as CO2 levels, and concluded the melting rate was not linear over time, contrary to the B.C. ministry's estimates. Rather, as temperatures rose with CO2 levels, the amount of melting reached a critical point at which feedback mechanisms kicked in and the rate of change increased exponentially.
The researchers say sea levels could be expected to rise by four to six meters by 2100 as part of a long-term trend towards five to ten meters. A six meter rise in sea level would put 91 per cent of Richmond, and 76 per cent of Delta underwater; the entire airport and ferry terminal at Tsawwassen would be lost to the sea; and the current erosion counter-measures around Point Grey and North Vancouver would be overwhelmed, threatening to plunge much of UBC into the ocean.
Some of the feedback mechanisms mentioned by Overpeck and Otto-Bliesner have started showing up already. The most common example of a feedback loop is the simple solar absorption model. Ice reflects more solar radiation and heat than water, so as the sea ice melts and more surface area is covered by water, more heat and light is absorbed. The increased absorption warms the water, which directly melts more water-based ice, and indirectly contributes to greater land-based ice loss, creating a cycle of warming that quickly takes off.
Modest plans for dykes
Thousands of hectares of land in the GVRD are protected by an extensive system of dykes, and the City of Richmond is in the process of updating these dykes to account for changes in the weather and sea level.
But city officials are basing the needed upgrades on a sea level rise of less than half a meter, significantly below even the B.C. ministry's top range of predictable rise. According to the Flood Protection Management Strategy, which provides the model for upgrading the dykes, these low figures are "considered the best information available at the time."
To protect the city from a one in 1,250-year flood -- a level of upgrade more in line with the higher B.C. government estimates of sea level rise -- the city would have to raise the barrier dykes by up to one meter, which would cost at least $90 million. Instead, the city is moving ahead with plans to protect only parts of the GVRD from a one in 200-year event based on the highest recorded water level in 1894, adequate only if the sea level rises by a mere half-meter.
Not just cost but a jigsaw puzzle of official responsibility is slowing attempts to prepare for the challenge. "I can't say 'let's raise the dykes by five feet' without all these departments signing off," said Terry Crowe, the manager of the policy planning division at the City of Richmond.
"Given the uncertainty," Crowe said, "why put money where you don't need to?"
When asked about the possibility of a higher level of sea level rise, Crowe said, "We did give it some serious thought and acknowledged that we needed to do more work."
Uninsured property worth billions
In the meantime, those living in places at high risk of flooding can expect to have few financial options.
In Canada, flood insurance is simply not available for places such as Richmond. The insurance industry reasons that if residents build their homes on a floodplain, such as Delta or Richmond, at some point the house will be flooded. This is considered by the insurance industry to be "uninsurable peril."
Currently, the British Columbia government offers Disaster Financial Assistance (DFA), a fund offering some reimbursement to homeowners who have suffered from uninsurable loss. However, the current plan is limited to a maximum of $300,000 per home and the average three-bedroom home in Richmond is now valued at close to half a million dollars. If Richmond and its surroundings were to flood, available DFA funds wouldn't begin to cover forecasted damages, and the additional cost to taxpayers could be huge. Property values in Richmond now top $30 billion.
Peter Nemetz, a professor at the Saunders School of Business at UBC, said of the latest rising sea predictions: "This is a legitimate signal to the people on the floodplain that they should consider the risks and rewards of building there."
Yet Richmond is one of the fastest growing areas in the GVRD. A rail-based rapid transit line linking Richmond to Vancouver is scheduled to begin operations in 2009, expected to fuel further development in these high-risk areas.
So far, real estate prices in Richmond and other low-lying coastal zones of B.C. do not seem to reflect the threat of sea level rise. But some industry watchers expect that to change, noting that people are unlikely to sink savings into property they know may be underwater within their children's lifetime. And they are asking whether government has a duty to warn potential buyers of the trends and even discourage development in such zones.
"Accelerated glacial melting and larger changes in sea level...should be looked at as probable events, not as hypothetical possibilities," state Brooks Hanson and Donald Kennedy, editors of Science.
Sea level rise is being brought about by a combination of factors: thermal expansion contributes most of the current rise in sea level and is supplemented by melting glaciers and ice sheets. Simply the fact that ice is melting is not enough, either. Ice is more voluminous than water, so the melting of water-based ice floating in the ocean has a negligible effect on water levels. When land-based ice, such as the Greenland Ice Sheet, parts of Antarctica, and land-based glaciers slide or melt into the ocean, however, the volume of the world's oceans increases substantially.
The global rate of loss for land-based ice increased dramatically over the past few decades. In Greenland alone, the rate has doubled since 1995 to approximately 225 cubic kilometres of melting and loss annually.
Differences in the way that ocean basins distribute heat and mass, as well as tectonic forces and other geological processes, cause sea level rise to differ across the planet and even regionally. Prince Rupert, for instance, experienced nearly three times as much rise in sea level over the last few decades as did the GVRD, which itself experienced more than the global average.
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