Human communities

BC has three major international ports, four regional ports, and 40 local harbours [74]. Within the MaPP region, Prince Rupert is the largest port with the capacity for shipping infrastructure and container ships.

Most communities within the MaPP region are highly dependent on marine infrastructure for transportation of goods and services; as support for the fishery and aquaculture industries; and for providing connections with other essential infrastructure and utilities such as roads, sewage systems, power and communications cables. The greatest threats to marine infrastructure in the MaPP region are likely to be sea level rise and increasing extreme weather events.

Sea level rise

Sea level rise already threatens coastal infrastructure, and the added risk of storm surge flooding increases the vulnerability of coastal infrastructure across the province [27,74]. Sea level rise is expected to inundate some of the critical infrastructure at the coastal areas. Some communities in BC have begun to take action to reduce the risk of sea level rise through investments in built infrastructure for shoreline protection as an adaptation measure [27]. Further adaptation examples can be found in urban areas near the Fraser River floodplain, an area that is highly vulnerable to sea level rise due to low lying geology and dense population.

A recent analysis found that the costs of sea level related damage to on-shore built infrastructure would be higher in coastal BC than any other coastal region in Canada [108].

Winds, waves, and extreme weather

Across the MaPP region, increasing intensity and frequency of storms is likely to increase inundation risk (flooding) and erosion risk to marine infrastructure, especially for low lying communities [109]. Properties along the coast also will experience increased risk of wave damage, which is associated with coastal erosion. It is highly likely that climate changes, especially during El Niño events, will lead to high coastal erosion across the entire eastern Pacific region [109].

Extreme weather events are expected to create disruptions to marine transportation lanes, potentially lead to wave and wind damage to infrastructure and utilities, and reduce access to critical services [110]. Extreme precipitation events in particular may damage fixed coastal infrastructure such as airports (e.g. Sandspit Airport on Haida Gwaii), and ports (e.g. Port of Prince Rupert), and well as affect marine transportation lanes [74,110]. Overall, climate-related impacts to marine infrastructure are likely to be higher than anticipated, as many communities in coastal BC already have infrastructure deficits that will require increased investment [91,103]. Future winter and spring sea surface height (SSH) levels are also projected to be consistently higher, which will further exacerbate the flooding impacts of sea level rise [21]. Large peak flows and storms can interrupt delivery of goods such as fuel and food to remote places. On the other hand, climate change may also offer some opportunities for the marine transportation sector: longer construction seasons and reduced winter maintenance could reduce costs and increase annual operating budgets. In the longer term, increased sea levels may mean that vessels with deeper draughts will be able to enter existing ports, perhaps an opportunity for marine shipping [110].

Fisheries and aquaculture are an especially important sector for coastal communities and First Nations. For many, fishing is a way of life which cannot be measured by the contribution to the economy alone, as the social and cultural values play a large role. Existing stresses and impacts on BC’s coastal fisheries are expected to be exacerbated by climate change, and in some cases (such as salmon), these impacts are already evident. The fishing industry has already declined significantly across the province: since the 1980s, the fishing fleet has shrunk by 60% and there are 70% fewer fishers employed in the industry [91]. The effects of climate change on fisheries in this region are reflected in projected species range shifts, in that the abundance of current target species is projected to decrease, and that the species currently available across the region are likely to change [12,17,92,93]. The impacts of these projected changes in fisheries catches could lead to or amplify other socio-economic impacts of climate change on fisheries and communities through reduced food security and economic loss [92].

Sea level rise

The associated impacts of sea level rise on land erosion and increased runoff is likely to directly affect nearshore species, especially filter feeders (shellfish) if water quality declines. Existing shellfish beds are likely to be affected, which will have implications for many species which depend upon the intertidal ecosystem for habitat and food, especially as juveniles (salmon, crab, eelgrass, algae, clams, humans) [94]. Spawning habitat for forage fish, and rearing habitats for invertebrates, could decrease or be lost due to erosion, subsidence, and submersion due to sea level rise [29]. This may be particularly problematic for Pacific herring, as that species prefers coastal marine algal species for spawning substrate, habitats that may potentially be lost as sea levels rise [29].

Sea surface temperature

The associated impacts of sea level rise on land erosion and increased runoff is likely to directly affect nearshore species, especially filter feeders (shellfish) if water quality declines. Existing shellfish beds are likely to be affected, which will have implications for many species which depend upon the intertidal ecosystem for habitat and food, especially as juveniles (salmon, crab, eelgrass, algae, clams, humans) [94]. Spawning habitat for forage fish, and rearing habitats for invertebrates, could decrease or be lost due to erosion, subsidence, and submersion due to sea level rise [29]. This may be particularly problematic for Pacific herring, as that species prefers coastal marine algal species for spawning substrate, habitats that may potentially be lost as sea levels rise [29].

Ocean Acidification

The effects of ocean acidification on fisheries are largely unknown, including on the important salmon and Pacific halibut fisheries [27,43; Appendix Table 2). In tropical fish, ocean acidification affects behaviour and results in increased mortality, but species responses in temperate regions are unknown [52]. Adult fish may be more tolerant of ocean acidification than early development stages, but there is limited research on life stage specific responses to pH for BC fishes specifically [52].

The effects of ocean acidification on shelled organisms, however, are much more understood ([52,99–101]. Aquaculture has the potential to improve food security and support remote economies. Across BC, capture fisheries landings are either in decline or somewhat stable, while aquaculture continues to grow (with some exceptions due to recent ocean acidification issues, e.g. Strait of Georgia, [102]). In the MaPP region, aquaculture is of great interest to coastal communities and First Nations. Currently, aquaculture operations in BC focus on salmon and other finfish, as well as shellfish including oysters and geoduck clams. Ocean acidification is likely to negatively affect shellfish aquaculture [99], and changes to oceanographic conditions including acidification are likely to affect finfish aquaculture as well [52]. The specific effects of ocean acidification on shelled molluscs varies by species, and a recent review suggested that acidification most negatively affects survival and shell growth (calcification), followed by respiration and clearance rates [99].

Ocean deoxygenation

Ocean deoxygenation will affect commercial fish species by reducing high quality fish habitat. Declining oxygen levels across the Pacific Ocean will contribute to the general decline and potential collapse of sessile (immobile) marine species, or sediment-dwelling organisms, as well as any other species who are intolerant of low oxygen levels. Declining oxygen levels are likely to especially affect groundfish species, whose habitat seems to already be decreasing by 2-3m per year, potentially related to declining oxygen levels [4]. Declining oxygen levels, and increasing hypoxia, will also likely affect aquaculture operations for vulnerable species, such as Dungeness crab and spot prawns [29]. Some hypoxia tolerant species (e.g. squid, jellyfish) may increase in abundance and/or distribution, potentially outcompeting less tolerant species (e.g. finfish) [54, 77].

Climate change will affect ecosystems throughout the region. The vulnerability of marine species to the cumulative effects of climate change depends on intrinsic adaptive capacities and sensitivities (based on biological or ecological traits), and extrinsic threats (impacts), such as increasing sea surface temperature or ocean acidification [86]. The cumulative effects of climate change on the food webs of the northeast Pacific may lead to a 30% reduction in total ecosystem biomass [17].

Air Temperature and Precipitation

Air temperatures are projected to increase at 0.3⁰C per decade in BC [72], still less than is expected across the country as a whole [43]. Melting glaciers will result in higher spring time water discharge into streams and rivers in the short term, while over time glacial retreat will likely lead to reduced water levels in glacier-fed streams, particularly during summer [10].

Due to the reduction in snowpack associated with decreased winter precipitation and warmer air temperatures, the spring runoff (freshet) will likely occur earlier in the spring in many rivers. This will have downstream effects on freshwater habitats, and linked marine systems [10,21], which will already be warmer and less oxygenated. These changes are likely to negatively impact the reproductive capacity and survival of fish and other aquatic species [6,87]. The sheer increase in freshwater volume entering coastal marine waters will also affect salinity and stratification of ocean surface waters.

Increased precipitation may lead to more runoff of contaminants and terrestrially derived nutrients – which, when combined with higher water temperatures, could increase the likelihood of toxic algae blooms in freshwater and marine ecosystems [29]. The increase in freshwater volume entering coastal marine waters may also decrease sea surface salinity and of ocean surface stratification. These stressors are likely to affect marine fishes and mammals that depend on nearshore habitats and are adapted to current oceanographic conditions [29].

Sea Level Rise

Sea level rise may affect coastal ecosystems through changes to habitat, especially for nearshore areas if important intertidal habitat becomes permanently sub-tidal, affecting nearshore plants, algae, and shellfish. Sea level rise is likely to cause an increase in the inland penetration of salt water in tidal systems. The abundance and species composition of coastal plants and algae, along with associated invertebrate habitats, could be altered if important intertidal habitat becomes permanently sub-tidal as sea levels rise [29].

Generally, coastal sensitivity to sea level rise depends on the physical geology of the coastline, and as such low-lying sandy regions will be most impacted. Most of the shoreline of BC has low sensitivity to sea level rise due to the rocky, fjordal coastline, but some areas (near Prince Rupert, Bella Bella, and most of Vancouver Island) are moderately sensitive (based on a recent provincial shoreline sensitivity analysis; [23]). Highly sensitive areas within the MaPP region include the northeast corner of Haida Gwaii [9,44]. For both the MaPP region and sub-regions, some moderate and high sensitive areas correspond with culturally important (First Nations) archaeological sites (see Map Section: Archaeological Sites Sensitive to Sea Level Rise Map, MaPP Region).

Sea Surface Temperature

Increasing sea surface temperatures are likely to affect zooplankton biomass, contributing to overall biomass declines of lower trophic level species [29]. Increasing ocean temperature and the northerly shift in the California Current may lead to higher abundance of low nutrient zooplankton, which would in turn affect juvenile fish species such as herring and salmonids [60,88]. Phytoplankton species composition is also likely to change, which could also affect higher trophic levels who depend on high quality zooplankton [17,58,60,89]. Kelps (giant kelp and bull kelp) and eelgrass (Zostera marina) are also likely to be negatively affected by warming sea surface temperatures; the cumulative impact of temperature along with decreasing salinity and increasing sedimentation from runoff will influence the productivity and distribution of these important habitat forming species [6].

Ocean Acidification

Ocean acidification will certainly continue to affect coastal BC [52], although there are significant knowledge gaps in terms of the effects of ocean acidification on marine organisms (Appendix 2 Table 2). Where data exist, it is more reliable for commercially viable shellfish species (e.g. oysters and other shellfish) and issues that may affect human health (e.g. harmful algae blooms) [52]. Already, the ocean below 300m depth is corrosive to aragonite shells, and it is likely that the saturation depth will continue to decrease, threatening shelled organisms and the fishes that feed on them, including Pacific salmon [4,52]. There is a strong likelihood that the negative impacts associated with ocean acidification could increase rapidly, and that the effects on marine species could potentially cause large shifts in species distribution and community assemblages across both latitude and depth [54].

Ocean acidification may affect habitat availability and the abundance of those species dependent upon calcifying organisms for structural habitats, and those whose larval stage is affected by a decrease in pH. For example, by 2100, cold water corals are projected to degrade due to ocean acidification, which will affect habitat availability for fish populations, therefore affecting fisheries productivity [54]. The effects of ocean acidification on trophic dynamics (food web interactions) and the synergistic effects of ocean acidification with other climate change projections, such as increasing ocean temperature and declining oxygen levels, are uncertain and requires further research [52,63].

Ocean deoxygenation

Ocean acidification will certainly continue to affect coastal BC [52], although there are significant knowledge gaps in terms of the effects of ocean acidification on marine organisms (Appendix 2 Table 2). Where data exist, it is more reliable for commercially viable shellfish species (e.g. oysters and other shellfish) and issues that may affect human health (e.g. harmful algae blooms) [52]. Already, the ocean below 300m depth is corrosive to aragonite shells, and it is likely that the saturation depth will continue to decrease, threatening shelled organisms and the fishes that feed on them, including Pacific salmon [4,52]. There is a strong likelihood that the negative impacts associated with ocean acidification could increase rapidly, and that the effects on marine species could potentially cause large shifts in species distribution and community assemblages across both latitude and depth [54].

Ocean acidification may affect habitat availability and the abundance of those species dependent upon calcifying organisms for structural habitats, and those whose larval stage is affected by a decrease in pH. For example, by 2100, cold water corals are projected to degrade due to ocean acidification, which will affect habitat availability for fish populations, therefore affecting fisheries productivity [54]. The effects of ocean acidification on trophic dynamics (food web interactions) and the synergistic effects of ocean acidification with other climate change projections, such as increasing ocean temperature and declining oxygen levels, are uncertain and requires further research [52,63].

Sea surface salinity

Changes in salinity can affect both sexual reproduction and vegetative propagation of seagrasses [29,90]. Declining salinity levels may affect the habitat, survival, and growth of marine fish and shellfish; in the Arctic, declining salinity has been shown to reduce phytoplankton size, which in turn affects productivity of higher trophic levels [54].

Other impacts

Changes in the timing of spring currents is also likely to affect biological interactions such as plankton availability, in turn affecting larval fish and invertebrates [29]. These changes could negatively affect marine fish and invertebrate recruitment, but the specifics of this impact are currently unknown [29].

Given the increasing rate of carbon emissions and the marginal success of global mitigation efforts, even higher rates of climate changes are expected in the future. Indeed, many of the impacts of climate change, including sea level rise, ocean temperature, and ocean acidification are likely to be worse than current projections [72]. Information on climate change projections, sectoral impacts, associated vulnerabilities and risks, and potential adaptation actions aim to inform policies that will ensure resilient communities and regions. A critical part of this process, therefore, is to include information on the social and economic status of the regions and communities. For example, information on climate change effects on the fisheries sector would be more meaningful if human dependencies on the fisheries sector is also known and included in vulnerability and risk analyses and recommendations of adaptation actions.

In the MaPP region, there is limited information on vulnerability and risk of predicted climate changes for human communities and sectors. While there is some information on exposure to climate impacts, data on adaptive capacity and sensitivity are largely not available across the region at this time. As such, based on the available literature and ongoing research, we comment on predicted climate change impacts from the climate change projections described in the previous section, and on probable exposure and risk to four key sectors: ecosystems, First Nations and non-First Nations communities, fisheries and aquaculture, and marine infrastructure. This information is provided at the MaPP regional scale and, where possible, further details are provided at the sub-regional scale. The MaPP regional level information is always relevant for the sub-regions, just at a coarse scale due to the quality of available data.