Salish Sea Rising

Coastal communities need to plan for one-metre higher seas within a century – and it turns out there are a tonne of resources to help them do that.

by Delores Broten

Vancouver, British Columbia

Thirty years ago, I was running the tiny Friends of Cortes Island office out of the community hall at Manson’s Landing. This led to many interesting and sometimes passionate conversations. One regular visitor was Basil Seaton, veteran of the internment camps for British soldiers in Burma during World War Two. Basil took it as his mission to educate me about climate change. I remember in particular a floppy disk he brought that contained various climate change scenarios.

Fast forward thirty years. My computer is more like a Ferrari than a horse and cart, and the Province of British Columbia advises communities to plan for one metre of sea level rise by 2100, and two metres by 2200. But the predictions are still all over the place, depending on the modelling used and the assumptions made.

It is indeed complicated.

We can start with the long long view. Over geologic time, sea level has fluctuated by at least 300 metres, largely dependent on the amount of water locked into the Antarctic ice caps. Changes in land formations and water temperature are also major factors.

But what about the here and now? The sea is slowly rising, but on the West Coast the land has also been rising for 11,500 years as the weight of the glaciers was lifted, and from the movement of the tectonic plates. The Educating Coastal Communities About Sea-level Rise (ECoAS) Project, a collaboration between the Ecology Action Centre in Halifax and Fisheries and Oceans Canada cautions: “Depending on your local conditions, the rate of sea-level change in your location can be substantially different from the rate of sea-level change globally and in other locations. In fact, sea-level in Charlottetown is rising almost two times the rate of global sea-level rise each year and relative sea-level projections for Halifax for 2010-2100 (relative to 1986-2005) are 28% larger than global values for the same time interval.” Rates of sea level rise for Haida Gwaii are predicted to be around 50-60 cm by 2100, and for Southern Vancouver Island, 50-70 cm.

ECoAS also notes that “Sea levels in BC during the El Niño cycle between 1976-2008 were on average 0.30-0.40m above normal.”

The Department of Fisheries and Oceans’ Canadian Extreme Water Level Adaptation Tool (CAN-EWLAT), created for small craft harbours, provides a map with projections of sea level rise and wave climate for 650 wharf sites on the coasts. For example, predicted levels for the Cortes Island wharves by 2100 seem to range between 0.13 and 0.4 metres, depending, of course, on what humans do in the next decade or two to limit the greenhouse gases we are packing into the atmosphere. However, with the Arctic permafrost melting and the taiga on fire in Siberia, it is now a question of adapting as much as possible.

To that end, the Islands Trust has prepared a document for the small islands in the southern Salish Sea, Climate Projections for Islands Trust Area, March 2020. The Islands Trust report divides its impact projections – such as length of growing season, precipitation, and ocean impacts – into four regions: Southern Gulf and Saltspring Islands, Gabriola & Thetis Islands, Howe Sound, and the Northern Gulf Islands.

Over the entire region, the hottest day is predicted to increase to 36 degrees celsius by 2080, growing season will lengthen, but so will summer droughts. Farmers and gardeners will have to adapt accordingly.

Certainly of concern to coastal people who love seafood are the projections for ocean stability: “Since the industrial revolution, ocean pH has dropped from 8.2 to 8.1, and is expected to decrease to an average of ~7.7 pH level by 2091-2100,” on the pH scale of 0-14 with anything under 7 being acidic.

Oxygen levels in the water are also falling: “Changes to oxygen levels are occurring rapidly in the North Pacific Ocean, where oxygen has already decreased by 22% at depths of between 100 and 400 m during the last 50 years.”

The impact to species other than humans is predicted to be quite severe, stressing both sensitive habitats and biological diversity, species ranges, and species health. The Islands Trust report is largely based on data from the Pacific Climate Impacts Consortium (PCIC) hosted by the University of Victoria. Along with much technical information, science publication reviews, databases, links to even more information, and up-to-date seasonal anomaly maps, PCIC has just launched a completely revamped tool for community planning, called Plan-to-Adapt.

This provides data, including map representations of predicted changes for every region of BC, and is simple and fun to use. For a deeper dive, the Fraser Basin Council hosts a site called ReTooling for Climate Change, with detailed manuals on planning for climate impacts on everything from transportation to natural resources.

The BC government also has a nifty guide for community planners, Sea Level Rise Adaptation Primer: A Toolkit to Build Adaptive Capacity on Canada’s South Coasts, with inclusion of the Atlantic resources such as legislation.

Sea Level Rise Adaptation Primer

The toolkit runs through planning tools, regulatory tools, land use change, structural tools such as hard armouring shorelines and soft armouring by activities like restoring wetlands, and rehabilitation of beaches or creation of dunes, to provide an adaptive buffer to sea level rise.

The authors caution “Adaptation tools included in this Primer should be considered in the context of information gathering, public education and community engagement, all crucial to informed decision-making processes within our democratic system.”

One can see a fine example of the attempt to engage community in adaptation planning in the City of Campbell River’s “Together for Climate: Managing Risk through Community Collaboration” project, where workshops, resources, and opinion polls are being used to help citizens shape the coming years in that city.

All these considerations need to become everyday life in urban, rural, and personal planning because one thing is certain, “the tides they are a-changing.”

Watershed Sentinel Oct Nov 2020 CoverThis article appears in our October-November 2020 issue.

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