The previous section included climate change projections and impacts at the scale of the BC coast and MaPP region. Here, we include additional projections and impacts that are specific to MaPP sub-regions, while emphasizing that all regional level projections and impacts are still relevant at the sub-regional level. Please reference the sub-regional tables for further details on sub-regional projections and sectoral impacts. Note that for many climate change variables, sub-regional resolution (finer scale) information is lacking or inconsistent (see section on knowledge gaps and recommendations).
Cape Caution, British Columbia, Canada | Photo by Scott Harris
Air temperatures on the north portion of Vancouver Island are expected to increase by 2050 to the same range as currently experienced in Vancouver [10,42], which reflects approximately 1.4°C warming relative to a 1960s-1990 baseline. Increasing air temperatures threaten fisheries and aquaculture through associated ocean warming which is likely to affect seasonality of traditional food resources as the summer season extends and frost-free days increase. There are potential benefits to tourism, an important sector in this sub-region, as the summer season lengthens and becomes warmer and more appealing.
Winter precipitation is predicted to increase in this sub-region, leading to increasing spring freshwater discharge that will also contribute to stronger flows in Queen Charlotte Sound [21,42,73]. Increased precipitation and stream discharge will increase flood risk to communities, while decreased summer precipitation will increase drought potential in summer months. Tourism may benefit as summer precipitation levels decrease, potentially attracting foreign visitors to outdoor recreation opportunities. However, winter snowfall is likely to decrease by as much as 33%, which could affect winter tourism and recreation.
Sea level rise projections are quite uncertain at the scale of MaPP sub-regions. Sea level rise will potentially not impact this sub-region as much as other sub-regions. By 2100, sea levels are projected to increase by approximately 14cm (range of 4.5 – 32.4cm), but may rise as much as 0.6m to 0.9m [21,44]. Rising sea levels are likely to impact the extensive aquaculture infrastructure in this region (finfish and shellfish), and producers will likely have to adjust the locations of some of their nearshore facilities. Commercial forestry, fisheries, and marine shipping sectors should take sea level rise projections (see North Vancouver Island Sea Level Rise maps) into consideration when planning future processing sites and harbor infrastructure. Commercial tourism facilities such as fishing lodges and marinas will also have to adjust their docks and other near-shore infrastructure to account for rising sea levels and increased storm surge events.
Sea surface temperatures will likely increase, and salinity will likely continue to decrease across the coastline and within this sub-region [55,82]. Average sea surface temperature is projected to increase on average by 1.8°C by the end of the century compared to 1961-1990 baseline [21,22]. Sea surface salinity will decline by ~1% to ~3% with by the end of the century 1961-1990 baseline as the ocean freshens with increased precipitation, terrestrial runoff, and melting glaciers [21,36]. Increasing sea surface temperatures will threaten fisheries productivity, especially for finfish which are sensitive to temperature, and lead to shifts in marine species distribution [92]. Rising temperatures and changing species distributions and abundance is likely to affect marine based food security for local communities. The commercial fishing industry is likely to continue to experience declining catch, particularly for temperature sensitive species such as salmon ([92,96,111]; Appendix 2 Table 1), and the extensive finfish aquaculture in this sub-region may also be affected .
Changes in ocean properties are also expected for the North Vancouver Island region. Ocean acidification is projected to continue, and average projections suggest that that ocean pH will fall to ~7.95 pH -7.68 pH under the IPCC high emissions scenario (RCP 8.5) by 2100 [32].
Some specific impacts at the scale of the North Vancouver Island sub-region are related to sea level rise and extreme weather events. There are numerous cultural and historic sites that may be particularly sensitive to rising sea levels based on recent shoreline sensitivity analyses (see North Vancouver Island Regional Shoreline Sensitivity Map). In particular, lower elevation foreshore or nearshore areas throughout the area are more likely to experience flooding and erosion.
Annual air temperatures in the Central Coast sub-region are expected to increase by approximately 1.6°C by 2050, which is similar to the current temperatures experienced in Vancouver [10,36,42] (see Central Coast Sub-regional Table). Summer precipitation is also predicted to increase in this sub-region, leading to increasing freshwater discharge will also contribute to stronger flows in Hecate Strait [21,42,73].
Changing precipitation patterns means that streamflow patterns are likely to change, such that summer stream flow is lower, with associated impacts to salmon and other anadromous or freshwater fish. It is possible that low flow conditions within the watershed could occur over the entire year, though generally they are likely to occur during the late fall and early winter. Within the context of future climate changes and related vulnerabilities of freshwater habitats, changes in the frequency, timing, and magnitude of such low flow conditions may have greater effects on salmon migration, spawning, and incubation than at present.
Sea levels are projected to increase within the Central Coast sub-region, but not as much as other sub-regions. Some specific impacts at the scale of the Central Coast sub-region are due to sea level rise and extreme weather events. Sea levels near Bella Bella are projected to rise by approximately 9 cm by 2100 (range -5.4 to 22 cm) (Thomson et al. 2008). However, localized land uplifting (+2.3mm per year) means that overall, the Central Coast sub-region is not likely to experience net negative impacts from sea level rise in the foreseeable future [44].
There are some cultural and historic sites that may be particularly likely to be affected by rising sea levels based on recent shoreline sensitivity analyses and locations of historic First Nations sites (see Central Coast Archaeological Sites Shoreline Sensitivity Map).
Sea surface temperatures are expected to increase by ~1.9°C by the latter portion of the century, with impacts to fisheries and communities through loss of fisheries landings and adjustments in fishery target species. Ocean acidification will increase, affecting calcifying organisms and the aquaculture industry. These changes will likely affect coastal communities, especially First Nations communities who rely on bivalves and other shellfish for food security and income.
Air temperatures in the North Coast region are projected to increase by up to 2.6°C by 2080, and the sub-region will experience more growing degree days, more frost free days, and higher winter minimum temperatures [73] (see North Coast Sub-regional Table). Rising temperatures will potentially decrease energy requirements for heating in the winter months, and potentially increase energy requirements for cooling in the summer months. Precipitation is projected to increase in the North Coast region by up to 20% in summer months, and by 10-25% in winter [73]. The increase in freshwater volume entering marine waters in this sub-region is likely to be greater than in other sub-regions due to large rivers, including the Skeena River, feeding into the marine area. This increase in freshwater volume will affect marine temperature, salinity, and stratification of nearshore surface layers[29,55]. Increasing freshwater discharge will also contribute to stronger flows in Dixon Entrance [21].
Relative sea level rise is projected to rise the most in the North Coast sub-region, specifically off Prince Rupert Harbour. Mean sea level rise projections for the port of Prince Rupert by 2100 suggest that sea levels will increase by approximately 25cm (range 13.2 – 37cm) with extremely high projections reaching 0.95-1.16m [6,44,68]. Sea level rise impacts are likely to be much higher for the North Coast when compared to southern BC, due partially to increasing precipitation in this sub-region [41,44,73].
Increasing sea levels and high water events are linked to beach erosion in this region; this impact has already been observed over the past two decades [107]. Models based on highest sea level events over the past century project that the frequency of storm-related high water events are likely to increase at twice the rate of the relative mean sea level trend for Prince Rupert, and the frequency of storm winds are also likely to significantly increase [107]. These projections will likely affect coastal communities through changes to food security,
Given the relationships among the PDO, ENSO, and low river flows, it is likely that climate-induced changes to hydrology will also occur in North Coast watersheds. Low flow conditions within the watershed can occur over the entire year, though generally are more prevalent during the late fall and early winter after summer drought. Within the context of future climate changes and related vulnerabilities of freshwater habitats, changes in the frequency, timing, and magnitude of such low flow conditions may have greater effects on salmon migration, spawning, and incubation than at present [41,112].
There are some cultural and historic sites that may be particularly likely to be affected by rising sea levels based on a recent shoreline sensitivity analysis overlaid with locations of historic First Nations sites (see North Coast Archaeological Sites Shoreline Sensitivity Map).
The average air temperatures in Haida Gwaii may increase by 1.4°C by the 2050s and by 2.2°C by the 2080s. The number of growing degree days will increase and frost free days will increase, as winter minimum temperatures may increase by up to 4-9°C by 2080 [10,42,70,71,73]. The average annual precipitation is likely to increase by 7% on average by the 2050s, and by closer to 9% by the 2080s ([73]; see Sub-regional Table, Haida Gwaii). Rising air temperatures and changing precipitation patterns are likely to threaten fisheries related tourism, yet may also provide potential benefits to the tourist season as the summer becomes warmer and longer. Increasing precipitation poses flooding risks to local communities in Haida Gwaii, which may affect access to traditional food gathering places. Increased spring runoff could damage coastal infrastructure, especially in the case of earlier freshet floods.
Sea level rise is projected to impact Haida Gwaii, especially low-lying areas along the east coast of Graham Island [21,25,85]. The coast of Haida Gwaii, especially the east coast of Graham Island, is highly dynamic; with sea level rise, the area is likely to erode as beaches and sand dunes migrate onshore. This sediment transfer is likely to cause shoreline retreat along coastal beaches (Walker and Barrie 2006). Previous projections by the Geological Survey of Canada have identified that area as among the top 3% most sensitive coastlines in Canada, due to the combination of low lying shoreline and easily eroded shorelines with large tidal ranges [69,107]. The ecosystems of Haida Gwaii are highly exposed to rising sea levels and increasing sea surface temperatures. Rising sea levels increase the risk of permanent inundation of important coastal habitats and can lead to loss of wetlands which are critical for bird and fish species. In addition, increasing sea surface temperatures are likely to diminish ecosystem health and alter coastal habitat composition [6]. There are also many cultural and historic sites that may be affected by rising sea levels based on a recent shoreline sensitivity analysis (see Haida Gwaii Archaeological Sites Shoreline Sensitivity Map).
Extreme storms and associated storm surge events are expected to intensify in this region due to the cumulative impacts of El Niño, the PDO, and sea level rise [69]. Previous El Niño events led to sea level rise and erosion along the same shoreline, and high water levels have since increased significantly [25]. Increasing winter winds are projected to increase seasonal currents and eddies near Rose Spit, Middle Bank, and Goose Island Bank [21]
Climate change impacts on fisheries in the area of the Queen Charlotte basin are somewhat uncertain [25]. While projections suggest declining species abundance and changing species compositions [92], the effects of warmer waters, altered production regimes, and exotic species have not yet produced obvious declines of herring and salmon in this area [25].
Climate change will impact the social, economic and environmental exposure of Haida Gwaii’s coastal communities. Particularly, sea level rise, and wind, wave and storms will have the highest direct impacts. Indirectly, changes in the ecosystems and fisheries and aquaculture will result in negative social and economic impacts on Haida Gwaii communities due to the high dependence to resource based life. Coastal communities and cultural and historical sites along the low-lying coastal areas of Haida Gwaii are the most exposed to rising sea levels, and winds, waves and storms. This is due to the increased likelihood of coastal flooding and erosion, and increased frequency, strength, and duration of storms and wind/wave action [31,42,107]. Increasing maintenance and insurance costs associated with the sea level rise and storm damages will also affect all Haida Gwaii communities [25].
Due to its geographic positioning, Haida Gwaii highly depends on its marine infrastructure for delivery of and access to goods and services, fishing and harvesting practices, and provisioning of utilities. Marine infrastructure in Haida Gwaii is increasingly exposed to climate change impacts, particularly to rising sea levels, and to increasing wave and wind actions from storms. The risk of marine transportation interruption is increasing due to increase in intensity, frequency and duration of storms, which will directly impact the delivery of goods and services, and access to the mainland [25].
Besides the marine transportation links and lanes, the infrastructure that supports the marine and land transportation is also likely to be affected by rising sea levels and heavy wind and wave actions. For example, the likelihood of damage to fixed coastal infrastructures, such as the Sandspit Airport, is likely to increase over time [74]. In addition, roads, utilities, power, communication, and flood protection infrastructures will experience inundation and/or structural damages with the increased risk of flooding, erosion and damage caused by rising sea levels, and wind and wave actions [25,42,113].
Haida Gwaii, British Columbia, Canada | Photo by Matthew Justice
Written by Charlotte K. Whitney and Tugce Conger
Whitney, Charlotte, and Tugce Conger. 2019. “Northern Shelf Bioregion Climate Change Assessment: Projected Climate Changes, Sectoral Impacts, and Recommendations for Adaptation Strategies Across the Canadian North Pacific Coast.”
Written by Charlotte K. Whitney, Tugce Conger, Natalie C. Ban, and Romney McPhie
Charlotte K. Whitney, Tugce Conger, Natalie C. Ban, Romney McPhie, and Steven J. Cooke. Synthesizing and communicating climate change impacts to inform coastal adaptation planning. FACETS. 5(1): 704-737. https://doi.org/10.1139/facets-2019-0027
