Climate change a threat to islanders, says geographer

  • Feb. 18, 2005 12:00 p.m.

By Mariah McCooey–The UVic professor studying the impact of climate change and sea-level rise on the islands says our way of life here is seriously threatened by these trends. Dr. Ian Walker gave a presentation in Skidegate last Tuesday night about his project, which has been underway for two and a half years.
Specifically of concern are the two airports (both barely above the high tide mark), the Old Massett cemetery, and Highway 16. Dr. Walker is not convinced the current solution-more rip-rap -is effective. The highway is a critical link, he said, and it clearly needs some better protection.
“The ocean will move those rocks,” he said, “you can’t stop the ocean. Maybe it’ll last 10 or 15 years, but another storm like that (Christmas Eve 2003) and it will breach.”
He said the reality is that the highway is too low, too close to the ocean, and with erosion happening at an astounding rate of 1-3 metres per year, it’s not going to last long. “And I don’t have a problem with saying that,” he added.
Dr. Walker is unimpressed with the work now underway. “I get a little upset,” he said, “I’m not a fan of shoreline hardening.” The steepness of the rip-rap barriers will do little to diffuse the energy of large waves, he said. Unlike a long, low slope, which slowly dissipates the wave’s energy, a steep face will get slammed with the full force of the wave, and its energy will bounce back, increasing the power of the next one. In addition, armouring one section of shoreline means that another section farther up the coast will sustain even more damage. The typical approach is to use “big stuff” he said, but it would be much more effective (although impractical) to use a long, low-angle slope which could be planted with vegetation. “But you’d have to build a dune right over the coffee shop,” he said. “It’s a very hazardous spot. Let’s just say that if I lived in Tlell, I would retreat.”
As far as options go, there aren’t many – harden, retreat, or adapt. “I don’t know what you could do at Tlell,” he said, “move the highway? I don’t know if that’s feasible or sustainable.” A more realistic approach, he said, is to focus on getting better services on the islands, so that the potential effects of rising sea levels wouldn’t be quite so devastating.
“People here are incredibly resilient,” he said, and part of the solution lies in building on already existing strengths of the community.
The east coast of Graham Island has already been identified as one of the most sensitive coastlines in Canada, along with parts of PEI and Nova Scotia, and the McKenzie River Delta in the north. In particular, northern sections of Naikoon Park and Rose Spit are eroding at a breathtaking rate of up to 10 metres per year, and this will only get worse, if the recent trends of rising sea levels are any indication. In 100 years, it is estimated that the global average sea level will increase by up to 90 centimetres. Although this may not sound like a lot, it doesn’t take into consideration factors like tides and waves, which will compound this amount.
The ocean is rising for several reasons: the increasing temperature of the water, which expands the molecules; melting glaciers; and declining salinity of the water. The waters around the islands have already increased by 1-2 degrees. But changes in the sea level are nothing new. Studies have shown that 12-13,000 years ago, the sea level around the islands was 150 metres lower than today. And aerial photographs show ancient shorelines kilometers inland from where they are now. But back then, Mr. Walker said, people were more self-sufficient. And they didn’t rely on roads, or electricity.
Now, because of our reliance on road and air transportation, we are in a much more vulnerable position. Fortunately, the Christmas Eve storm peaked at low tide, which was nearly miraculous.
“It could have been much worse,” he said. Surprisingly though, in the 100 year record, there are no instances of storm surges occurring on a high tide. Although this is anecdotally known among mariners, Mr. Walker has not yet discovered any scientific basis for it. “It could be pure luck, or just a matter of timeÂ… the right combination of things, or maybe the wrong combination of things.”
Professor Walker is convinced that climate change and rising sea levels are real, and that they will have real consequences, including increased frequency and ferocity of storms and more extreme weather. Whether or not we can do anything about it is somewhat dubious though – even if we halted all greenhouse gas emissions, there is already a process in place that is irreversible. What is important now is the development of locally relevant strategies to adapt to ongoing climate change, so that impacts are minimized.
“You can’t control the ocean,” he said, “it’s incredibly difficult and expensive.”