Rising sea levels are a global issue, but research shows the danger is greater closer to home.
Karen Kohfeld, SFU assistant professor and Canada Research Chair in Climate Resources and Global Change explained, “We can expect a global sea rise of 70 to 100 centimeters if we do nothing to change our carbon emission. If we do something about it, we can reduce it to about 40 to 60 centimeters.”
Vancouver is one of the more threatened cities, and mayor Gregor Robertson is calling for more aid from the federal and provincial governments to help save the coastal city from the impacts of rising sea levels.
According to Global News, a local study estimates $25 billion worth of real estate will be at risk from sea level rise in Vancouver by the end of the century.
“The low-lying areas will be most affected,” Kohfeld said. “If we look at just our global topography in places like Vietnam, any place that has a major industrial port by the sea, will be affected by this. The southern coast of North America and the east coast of North America will be affected.”
Preventative work is already underway in some places around the world. Kohfeld continued explaining that, for example, New York and Tokyo are likely to spend billions to erect dikes and other defenses.
However, not all cities can afford this. Kohfeld said, “[For] other places in the world, island nations around the globe, this a serious concern. Whenever we have international climate treaty meetings sponsored by the UN, the island nations are always there because part of the problem is it is not just looking out and seeing the sea level rise. It is that when the sea level goes up, and you have any kind of storm coming over top of that, that’s when you see the large problems.”
Recent findings have shown that a key glacier in west Antarctica is melting, which researchers suggest will contribute to an additional sea level rise that may reach a couple of feet in this century.
According to Kohfeld, the outlook seems bleak: “One of the studies suggest it is beyond the point of return for this particular glacier. The concern there is that where that glacier is located, it is kind of a lynch pin for all of western Antarctica, that ice sheet. The question is, ‘How stable is the ice sheet behind that glacier?’”
In particular, for BC, the extensive dike system would have to be modified. “If we are to account for a one metre sea level rise, one option would be to raise those dikes. That is very costly,” Kohfeld warned.
Kohfeld reflected on mistakes of the past and asked, “What should we have done already?”
I believe it’s reasonable to expect a four-meter rise in sea levels within a few centuries based on recent studies of the pending, perhaps inevitable collapse of the West Antarctic Ice Sheet. The inherent instability of that ice plus natural variations in global temperatures have led to its collapse repeatedly over geologic history – Look up recent stories on “meltwater pulse 1A” for more information.
There are precedents for a sea level of about four meters higher than present based on climate studies of recent interglacial periods, in particular the last one spanning from about 130,000 to 114,000 years ago. During the present interglacial, which began about 13,000 years ago, the climate has warmed rapidly just as it did during at least the previous several cycles of roughly 100,000 years. The record is clear based on studies of ice cores taken in Greenland and Antarctica.
It’s not a coincidence that we are having conversations about global warming now – The present warming cycle opened up large areas of Europe and North America to human habitation and helped make our civilization possible. Most of the present warming occurred before the invention of written language.
Vancouver is fortunate to be in a modern, resource-rich nation with plenty of minds and bodies to put to work on the problems that will come with what should be regarded as inevitable sea level rise. I frankly think it’s unrealistic to believe that the increase could be limited to 40 to 60 centimeters with what we know now about Antarctic ice and recent peak interglacial climates, even if humans were to completely stop burning fossil fuels right now. Plan for four meters, and we should have several generations in which to prepare for and deal with it.
The comment by David just below is well founded. To use a meter as a worst case for SLR this century is quite misleading and to state that if things go well that it will only be 40 – 60 cm, is similar.
The major studies like the IPCC, do not include figures for catastrophic collapse of ice sheets in Antarctica, exactly the kind of scenario that has been described in scientific journals in the last few weeks. This is a common misunderstanding even in the scientific and research communities. Essentially they are answering the question “How much SLR will we get this century that we can quantify from known sources to a high degree of confidence”.
Even though we can see the signs of possible collapse that could cause several meters of SLR, they do not count that because it cannot be quantified at this time.
With risks where we have experience and statistics, like fire and earthquakes, we look at probabilities. We can’t do that with ice sheet collapse. The last time it happened was fourteen thousand years ago. Bach then sea level rose 20 meters in four centuries. We are warming MUCH faster now. We need to talk honestly about the range of scenarios for what could happen in the next half century.
We can do great things if we are realistic about framing the range of scenarios and challenging ourselves.