Synthesizing and communicating climate change impacts to inform coastal adaptation planning

Air temperatures have increased throughout BC by ∼1.3 °C over the past century (from 1900 to 2013; 0.12–0.13 °C per decade (Rodenhuis et al. 2006; PCIC 2013a; BCME 2016; Vadeboncoeur 2016), slightly more than the global average during the same period (IPCC 2014b) but less than the rest of Canada (Warren and Lemmen 2014b). Most of this warming trend has been observed during the winter months (average increase of 2.2 °C per century), and in the north (3–3.8 °C per century) and south-central (2.6–2.9 °C per century) areas of BC (Rodenhuis et al. 2006; BCME 2016). Average daily minimum temperatures have increased the most (increased 2.3 °C this century) across the province, while average daily maximum temperatures have increased by 0.7 °C per century (BCME 2016; Chandler et al. 2017). Both daily average and daily minimum air temperatures in BC reached record high levels in 2016; monthly temperatures in the winter of 2016 were more than 5 °C higher than the baseline period of 1971–2000 (Chandler et al. 2017). These higher temperatures negatively as well as positively affect ecosystems and human activities. Increasing air temperatures have been associated with decreased heating requirements over the past century in BC, especially in northern BC (BCME 2016), while the energy demand for cooling infrastructure has increased, especially in the southern interior of BC (BCME 2016). BC is expected to experience more warming than the global average (Pike et al. 2008; Spittlehouse 2008); air temperatures are projected to increase by 1.8 °C by the 2050s and 2.7 °C by the 2080s, and could reach of 3–5 °C by the end of the 21st century (Pike et al. 2008; Spittlehouse 2008; Mote and Salathé 2010; PCIC 2013b; Fig. 3).

Average annual sea surface temperatures have warmed between 0.6 and 1.4 °C per century across the coast of BC (BCME 2016), as monitored at lighthouse stations along the BC coastline. This rate is similar to the global average of 1.1 °C per century (IPCC 2013; BCME 2016), although some areas have warmed by up to 2.2 °C per century (e.g., Strait of Georgia, Entrance Island) (BCME 2016). In BC waters, recent sea surface temperature trends have been the result of climate change warming, El Niño effects (2015–2016), and the “warm blob” phenomenon (2013–2016) where a large area of very warm water (3 °C warmer than usual) settled off the BC coast (Bond et al. 2015; DiLorenzo and Mantua 2016). In 2016, average sea surface temperatures were 1–2 °C warmer than the historical average within the Northeastern Pacific Ocean (Chandler et al. 2017). Sea surface temperatures are likely to increase by between 0.5 and 2.0 °C by the end of the century (Foreman et al. 2014; Fig. 3).

Globally, ocean acidification is projected to increase by 100% or more by 2100, but there is large uncertainty and variation among regions and climate scenarios (IPCC 2013; Haigh et al. 2015; Weatherdon et al. 2016a). Ocean acidification is occurring faster as higher latitude areas, due to the effects of temperature on carbon dioxide absorption (Byrne et al., 2010; Doney et al., 2012; Gerber et al., 2014). In the Northeastern Pacific Ocean, ocean acidification is one of the most urgent threats to both marine ecosystems and human communities as these waters are already among the most acidic of the world’s ocean regions, due to ocean currents and upwelling of deep ocean waters (Okey et al., 2014; Haigh et al., 2015). Within the NSB, acidification is projected to continue to increase as carbon dioxide emissions continue to rise. The existing state of knowledge for ocean acidification is limited, and other than global data sets, there are currently no projections at the scale of the BC coast (Hunter et al. 2015). This is partly due to a lack of empirical data as model inputs. Sampling for alkalinity and dissolved organic carbon has occurred as a regular part of Fisheries and Oceans Canada (DFO) surveys since 1992 and 1986, respectively, but the data have been fragmented and inconsistent (Hunter et al. 2015). Ongoing efforts to model changes in ocean chemistry (nitrogen, carbon, and oxygen) will improve the overall understanding of coastal biochemical processes and nearshore acidification and hypoxia levels (K. Hunter, Fisheries and Oceans Canada, personal communication, July 2017). In addition, further efforts to model changes and extremes in pH (Hunter and Wade 2015; Ianson and Monahan unpublished data) will improve the understanding of projected changes in acidification and the associated impacts.

Across the NE Pacific Ocean, dissolved oxygen levels have been declining over at least the past several decades, at a range of depths from 100 to 1000 m deep down to the sea floor, and oxygen levels between 100 and 400 m depth have decreased by 22% over the past 50 years (Okey et al. 2014). Oxygen levels are likely to continue to decline in the northeast Pacific Ocean, and coastal shelf and slope marine ecosystems are likely to lose well oxygenated habitats (Whitney et al. 2007; Fig. 4). Seafloor habitats in the North Pacific could experience a reduction of 0.7%–3.7% in oxygen levels by 2100 (Sweetman et al. 2017).

In BC, the average sea level between 1910 and 2014 has risen along most of the coast, at a rate of 13.3 cm/century at Prince Rupert, 6.6 cm/century at Victoria, and 3.7cm/century at Vancouver (BCME 2016). Sea levels at Prince Rupert and Victoria continue to increase, while off the west coast of Vancouver Island tectonic uplift offsets sea level rise such that water levels appear to be declining (removing this uplift would result in a sea level increase of 13.5 cm per century) (BCME 2016; Chandler et al. 2017). Changes in sea level threaten coastal systems through coastal erosion, seawater inundation, and contamination of freshwater systems, and they can affect food crops grown in low lying areas. Relative sea level across the coast of BC is projected to rise by an average of 20–30 cm by 2100 (Fig. 3). However, there are many uncertainties in the projections for sea level rise, and local ocean currents, tidal patterns, and river discharge rates will influence the observed rate of sea level rise to particular areas. For instance, some models project higher observed sea surface height (SSH) values along the northern coast of BC during the next century in winter and spring related to wind patterns and increasing river discharge (Foreman et al. 2014).

Ocean salinity is declining globally, along the BC coast, and within the Northern Shelf Bioregion (Chandler 2017). Empirical data from lighthouse station monitoring stations in 2016 reflect a long-term trend towards decreasing sea surface salinity across the BC coast, except within the Strait of Georgia (Chandler 2017). Longer-term data from lighthouse station monitoring shows the same freshening trend; however, this is not associated with longer-term climate trends but with local freshwater sources (Cummins and Masson 2014). Freshwater discharge from glaciers is a significant contributor to the nearshore waters of BC. Glacial coverage in BC has declined since 1985, and the volume of glacial ice declined by an average rate of 21.9 km³ from 1985 to 2000 or by approximately 6.4% from 1985 to 2000 in the coastal region (BCME 2016). Coastal runoff contributes to maintaining the salinity levels along the coast, driven by glaciers as well as watersheds driven by fall and winter seasonal precipitation. Large river systems (Fraser River, Naas River, and Skeena River) drain large watersheds and experience pronounced spring freshets that affect coastal salinity levels more than large-scale climate changes (Cummins and Masson 2014).

Precipitation is a key indicator of climate change, and changes will affect all sectors, ecosystems, and communities. In BC, precipitation has increased over the last 50 years in all seasons by some estimates, or just in the summer months by other reports, with variation across the province (Rodenhuis et al. 2006; Walker and Sydneysmith 2008; Okey et al. 2014). Province-wide, annual average precipitation has increased by 12% per century (BCME 2016). However, these changes have been so far statistically insignificant and can largely be explained by the high natural variation in precipitation patterns across the province (PCIC 2013a; BCME 2016; Vadeboncoeur 2016). Winter warming trends led to higher snowpack density (wetter snow) across much of BC from 1950 to 2014, and as winter temperatures increase, winter snows are likely to continue to be wet and heavy or be replaced by rain (BCME 2016). Changes in the amount, type, and timing of precipitation in BC will certainly affect both terrestrial and marine systems, although the relatively high uncertainty in historical monitoring data—and the implications of these changes—means that estimating current precipitation trends and associated impacts is a challenge (BCME 2016).

Projected changes in precipitation in BC are expected to be relatively minor, especially when compared with the historical variability in the province (Fig. 3). Wetter winters are projected to lead to increased runoff in rivers and streams in the winter. Less precipitation will fall as snow in the winter, which is likely to result in a reduction of the spring snowpack by 55% by 2050 (Rodenhuis et al. 2006). Due to this reduction in snowpack, the spring freshet will likely occur earlier in the spring in many rivers. By the end of the century, spring streamflow will likely have increased significantly, while summer river levels will have decreased (Thomson et al. 2008).

Extreme precipitation events will likely increase during some seasons and in some areas of the province (Rodenhuis et al. 2006; Pike et al. 2008; Mote and Salathé 2010; Okey et al. 2014; Fig. 3). Heavy precipitation events in BC include phenomena known as “atmospheric rivers” where highly concentrated water vapour streams move moisture from tropical regions towards the poles. These occur frequently in the fall and winter in BC, and impact coastal areas with periods of intense precipitation and flood events (Rodenhuis et al., 2006; Pike et al., 2008; Nyland and Nodelman, 2017). More frequent atmospheric river events after 2040 (approximately double the current number per year) will affect ecosystems along the coast (Nyland and Nodelman 2017). Changes in wind and wave patterns may interact with other climate change projections such as sea level rise, but the projections of future winds and storm events are highly uncertain (IPCC 2014b). Storm intensities in the North Pacific increased during 1940–1998, and storm surge related winds and storms may become more frequent and intense as air and ocean temperatures increase (Dolan and Walker 2006; Thomson et al. 2008).

Increasing sea surface temperatures and declining oxygen levels have affected the northern Pacific Ocean, which has likely led to reduced habitat availability and decreased survival for many fishes and invertebrates (Whitney et al. 2007). The warm blob (2014–2016), a mass of water characterized by water temperatures from 1 to 3 °C above the 30-year average, developed off the west coast of BC, affecting phytoplankton community composition, ocean stratification, and associated with abnormal and dramatic species range shifts (Chandler et al. 2017). Harmful algae blooms during the warm blob event could also be associated with climate warming (Perry and Peña 2016). During that event, warm water zooplankton were much more abundant than cold water species in 2016, with potential implications for fish as warm water zooplankton species have lower nutrient quality (Perry and Peña 2016). Other unusual biological events during that anomalously warm water period included low chlorophyll levels (2014), potentially due to increased stratification and reduced nutrients (Whitney 2015). Species sightings that could indicate dramatic species range shifts include ocean sunfish and warm water sharks off Washington State and Alaska, high catches of albacore tuna off the Washington and Oregon coasts, juvenile pompano sightings near the Columbia River, and widespread stranding of Velella velella off the coast of BC throughout the summer of 2014 (Bond et al. 2015). Warm ocean temperatures have affected the waters off the west coast of Vancouver Island, and the zooplankton community has shifted to more gelatinous species (overall lower nutrient food) and less crustaceans, leading to poor forage conditions for juvenile fish and seabirds (Galbraith and Young 2017). Further increasing sea surface temperatures are likely to affect zooplankton biomass, contributing to overall biomass declines of lower trophic level species (Hunter and Wade 2015). 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 (Cleary et al. 2016; Galbraith and Young 2017). Phytoplankton species composition is also likely to change, which could also affect higher trophic levels who depend on high-quality zooplankton (Ainsworth et al. 2011; Johnson et al. 2011; Perry and Peña, 2016; Galbraith and Young 2017). 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 (Okey et al. 2012). Projected changes to climate variables are likely to interact to affect the likelihood of species invasions in BC waters, as habitats and oceanographic conditions change to facilitate the establishment of warm water species through species range expansions (Bond et al. 2015; Cheung et al. 2015). Marine diseases are also likely to increase in frequency and intensity, as species already stressed due to direct climate changes such as rising ocean temperatures are also more susceptible to infection (Okey et al. 2014). The biological interactions and additive effects of disease and invasive species, such as green crab which is already invading BC waters (Gillespie et al. 2015), are highly uncertain (Clarke Murray et al. 2014; Okey et al. 2014; Jones and Cheung 2017).

Ocean acidification will certainly continue to affect coastal BC, although there are significant knowledge gaps in terms of the effects of ocean acidification on marine organisms (Haigh et al. 2015). Where data exist, it is more reliable for commercially viable shellfish species (e.g., oysters) and issues that may affect human health (e.g., harmful algae blooms) (Haigh et al. 2015). Already, the ocean below 300 m 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 (Cummins and Haigh 2010; Haigh et al. 2015). 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 (Sweetman et al. 2017). 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 decreasing 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 (Sweetman et al. 2017). 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, require further research (Haigh et al. 2015; Hunter et al. 2015).

The expansion of low oxygen zones will affect ecosystem structure and function, especially in the deep sea (Sweetman et al. 2017) and in the deep coastal fjords of the northern coast of BC due to their geomorphological and chemical conditions (Okey et al. 2014). Deoxygenation at deeper depths may drive mobile marine species to seek refuge in shallow water; yet, those habitats will be more likely to be too warm. This interactive effect may result in physiological stress or species interactions. The combination of warming temperatures in shallow depths and deoxygenation at deeper depths may lead to habitat compression, unless species can adapt by migrating along continental slopes into more oxygenated environments, where they exist (Sweetman et al. 2017).

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, with downstream effects on freshwater habitats and linked marine systems (Foreman et al. 2014; BCME 2016). This is likely to negatively impact the reproductive capacity and survival of fish and other aquatic species (Rand et al. 2006; Okey et al. 2012). The sheer increase in freshwater volume entering coastal marine waters will also affect salinity and stratification of ocean surface waters. Changes in the timing of spring currents are also likely to affect biological interactions such as plankton availability, in turn affecting larval fish and invertebrates (Hunter and Wade 2015). The specifics of this impact of species recruitment are currently unknown (Hunter and Wade 2015).

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 (Hunter and Wade 2015). The increase in freshwater volume entering coastal marine waters may also decrease sea surface salinity and increase 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 (Hunter and Wade 2015). Changes in salinity can affect both sexual reproduction and vegetative propagation of seagrasses (Hunter and Wade 2015; Rahman et al. 2017). 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 (Sweetman et al. 2017).

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 (Hunter and Wade 2015). 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 (Biffard et al. 2014).

For many coastal communities and First Nations, fishing is a way of life that cannot be measured by the contribution to the economy alone, as social and cultural values play a large role. The fishing industry has already declined significantly across the province because of multiple factors including overfishing and fleet restructuring; since the 1980s, the fishing fleet has shrunk by 60% and there are 70% fewer fishers employed in the industry (Foundation TBSE 2015). Existing stresses and impacts on BC’s coastal fisheries are expected to be exacerbated by climate change, in particular for those species that are highly vulnerable to warming conditions (e.g., salmon; Healey 2011; Cheung et al. 2015; Weatherdon et al. 2016b). Some of the effects of climate change on fisheries in this region are reflected in projected species range shifts: the abundance of current target species is projected to decrease, and the species currently available across the region are likely to change (Ainsworth et al. 2011; Cheung et al. 2015; Teh et al. 2016; Weatherdon et al. 2016b). 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 (Weatherdon et al. 2016b). Fisheries and Oceans Canada has an ongoing project to model climate change vulnerabilities in some fisheries, and other work is focused on modeling the impacts of warming river temperatures on juvenile salmon (K. Hunter, Fisheries and Oceans Canada, personal communication, July 2017).

In southern BC, the impacts of warming freshwater and marine water temperatures have been observed, leading to declining productivity and diminished returns of Fraser River sockeye salmon (Walker and Sydneysmith 2008). Low returns of Fraser River sockeye salmon have been observed (e.g., returns in 2016 were the lowest on record) (Grant et al. 2017), and Fraser River sockeye were recently recommended for listing with the Species at Risk Act (Semeniuk 2017). While observations and field evidence are still limited, the interacting effects of ocean temperature and acidification are also of critical concern for many taxa (e.g., molluscs, corals, and calcareous algae). Ocean acidification has affected calcifying organisms, especially larval survival in the oyster aquaculture industry (e.g., Strait of Georgia; Hunter et al. 2015; Ianson et al. 2016a, 2016b). Melting glaciers across BC may also be releasing historical pollutants into freshwater ecosystems, also affecting freshwater fish and downstream marine areas (Whitney 2017). Increasing rates of ocean acidification are likely to negatively affect calcifying organisms, many of which are important for aquaculture and traditional food resources, including molluscs, bivalves, sea urchins, and sea cucumbers (Haigh et al. 2015; Ianson et al. 2016a).

Further fisheries responses to climate change impacts will vary both regionally and by species (Walker and Sydneysmith 2008; Table 1). Species particularly vulnerable to increasing ocean temperatures include Pacific salmonids (Crozier et al. 2008; Healey 2011; Martins et al. 2011; Muñoz et al. 2014). For example, there is a 17%–98% chance of “catastrophic” loss of a Chinook salmon population by 2100, depending on the emissions scenario (Muñoz et al. 2014). Many fish species may expand their range northward (at an average rate of 10–18 km/decade), and in many cases, their abundance may decline precipitously (Walker and Sydneysmith 2008; Ainsworth et al. 2011; Weatherdon et al. 2016b). These impacts are more severe at higher latitudes, so that the relative catch potential is projected to decline more in the North Coast, Haida Gwaii, and Central Coast than southern BC waters (Weatherdon et al. 2016b). Pelagic fisheries that may be especially affected by increasing sea surface temperature include Pacific herring, Pacific sardine, and Pacific salmon (Hunter and Wade 2015; Weatherdon et al. 2016b). Warming ocean surface temperatures will also likely decrease the habitable range of sessile species such as shellfish, which are less likely to be able to move northward at the rate of climate change. However, species’ responses to climate change will also depend on species-specific adaptive capacity and sensitivity; assessing species-specific responses to climate change is highly limited by the lack of data on species traits and potential adaptive responses (Jones and Cheung 2017).

The effects of ocean acidification on fisheries are largely unknown, including on the important salmon and Pacific halibut fisheries (Haigh et al. 2015; Hunter et al. 2015; Table 1). In tropical fish, ocean acidification affects behavior and results in increased mortality, but species responses in temperate regions are unknown (Haigh et al. 2015). 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 (Haigh et al. 2015). The effects of ocean acidification on shelled organisms, however, are much more understood (Cooley et al. 2009; Gazeau et al. 2013; Ekstrom et al. 2015; Haigh et al. 2015). Acidification will affect fisheries through negative impacts on food web dynamics and lower trophic level organisms (Lynn et al. 2013). Shellfish are likely to be affected across life stages, and this decline in economically important species (oysters, scallops, abalone, and mussels) will affect the economies of coastal communities in the region. In the Northern Shelf Bioregion, aquaculture is of great interest to coastal communities and First Nations. Ocean acidification is likely to negatively affect shellfish aquaculture (Gazeau et al. 2013), and changes to oceanographic conditions including acidification are likely to affect finfish aquaculture as well (Haigh et al. 2015). The specific effects of ocean acidification on shelled molluscs vary by species, and a recent review suggested that acidification most negatively affects survival and shell growth (calcification), followed by respiration and clearance rates (Gazeau et al. 2013).

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 deep water habitat seems to already be decreasing by 2–3 m per year as deoxygenated strata increase (Cummins and Haigh 2010). Declining oxygen levels, and increasing hypoxia, will also likely affect aquaculture operations for vulnerable species, such as Dungeness crab and spot prawns (Hunter and Wade 2015). Some hypoxia tolerant species (e.g., squid and jellyfish) may increase in abundance and (or) distribution, potentially outcompeting less tolerant species (e.g., finfish) (Doney et al. 2012; Sweetman et al. 2017).

The associated impacts of sea level rise on land erosion and increased runoff is likely to directly affect nearshore species. Existing shellfish beds are likely to be affected, which will have implications for many species that depend upon the intertidal ecosystem for habitat and food, especially as juveniles (salmon, crab, eelgrass, algae, clams, and humans) (Lynn et al. 2013). 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 (Hunter and Wade 2015). This may be particularly problematic for Pacific herring as coastal marine algal species and habitats used for spawning may be lost as sea levels rise (Hunter and Wade 2015).

Coastal First Nations and non-First Nations communities depend on the ocean and nearshore environments for economic, social, and cultural values. The coastal economy of British Columbia is largely based on the recreational tourism (33%), transport (29%), and seafood (12%) sectors (Foundation TBSE 2015, 2017). These communities are at risk for land loss, damage to coastal infrastructure, and changes to resource availability, all of which will affect coastal values (Walker and Sydneysmith 2008). Especially for First Nations communities, access and availability of traditional foods has decreased as ecosystems have been exploited or converted to other uses, and the productivity of remaining intact ecosystems has been impacted by factors including pollution, management actions, or invasive species. An example of an observed impact of climate change on community food security is the changing timing of wild plant ripening and harvest (Turner and Clifton 2009; Lynn et al. 2013). Increasing ocean temperatures will impact coastal communities that are reliant on fisheries and other marine species for food security and economic activities. Many species that are currently important to coastal communities (First Nations and non-First Nations) are projected to shift northwards from their current species range (at rates of 10–18 km/decade) and also decline in relative abundance (up to ∼40% decline depending on the species and climate scenario) (Weatherdon et al. 2016b). Decreased access to these traditional foods also has implications for human health and culture (CIER 2006).

Increasing storm surge events have been observed along the BC coast, along with an increasing frequency of “king tide” events. First Nations cultural sites may be impacted by rising sea levels, storm surge, and king tide events. For example, cultural sites near Prince Rupert and Metlakatla are experiencing erosion and loss of cultural artifacts (A. Paul, personal communication, 24 November 2017). First Nations communities have observed changes to seasonality of local food gathering practices (Turner and Clifton 2009). Increasing sea levels may be affecting coastal built infrastructure (Walker et al. 2006; Sales 2009), and increasing frequency and intensity of storm events may affect marine infrastructure (at sea and near-shore; Walker and Sydneysmith 2008). Increasing intensity and frequency of storms is likely to increase inundation risk (flooding) and erosion risk to marine infrastructure, especially for low-lying communities (Barnard et al. 2015). 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 (Andrey and Palko 2017). Extreme precipitation events may damage fixed coastal infrastructure such as airports (e.g., Sandspit Airport on Haida Gwaii) and ports (e.g., Port of Prince Rupert) (Andrey and Palko 2017; Nyland and Nodelman 2017).

Most communities within the NSB are highly dependent on marine infrastructure. The greatest threats to marine infrastructure in the NSB are likely to be sea level rise and increasing extreme weather events. Sea level rise will not affect areas along the BC coast equally because of differences in vertical land movement (Warren and Lemmen 2014b). Notable cases include the northeastern coast of Graham Island, Haida Gwaii, an area which is amongst Canada’s most sensitive coastlines to climate change (Walker and Sydneysmith 2008). In addition, groundwater quality could decline due to saltwater intrusion as sea levels rise (Walker and Sydneysmith 2008). Sea level rise already threatens coastal infrastructure, and the added risk of storm surge flooding increases the vulnerability of coastal infrastructure across the province (Lemmen et al. 2016; Nyland and Nodelman 2017).

Overall, climate-related impacts to marine infrastructure are likely to be high, especially as many communities in coastal BC already have infrastructure deficits that will require increased investment (Foundation TBSE 2015, 2017). Future winter and spring SSH levels, which can be due to the expansion of warming waters, are also projected to be consistently higher, which will further exacerbate the flooding impacts of sea level rise (Foreman et al. 2014). 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. Over time, increased sea levels may mean that vessels with deeper draughts will be able to enter existing ports (Andrey and Palko 2017).

Climate change impacts are likely to continue to unevenly affect communities along the coast because of different exposures to those impacts. An added dynamic is that any climate-related impact has a cumulative effect on nonclimatic issues already affecting these communities, such as declining resource industries, economic or social restructuring, and ongoing land claims agreements in the case of First Nations. Other impacts on human communities include changing energy demands for heating, which have declined for buildings across BC, especially in northern BC, as average air temperatures have increased (BCME 2016). It is likely that increasing air temperatures, especially during extremely high temperature events, will lead to greater incidence of heat stroke and potential mortality (Henderson et al. 2013). However, increasing air temperatures may attract more tourism for a longer summer season, which will have positive economic implications for coastal communities. In general, rural and remote communities in BC tend to have a lower socio-economic index, indicative of economic hardship, education, health, and other risk factors (Huang et al. 2012; Islam et al. 2014). These trends suggest low adaptive capacity to manage large stressors like climate change (Foundation TBSE 2015).

As fish distributions and abundances shift with climate change, fisheries will have to adjust by changing target species, fishing areas, fisheries openings, and processing locations (Pinsky and Mantua 2014; Morrison and Termini 2016). Scenario planning exercises can help to identify management options to move the spatial extent of fisheries or add value to fishery products if landings are projected to decline. For instance, adjusting fisheries regulations and harvest licensing prior to species shifting their range could allow fishers to target new species and exotics as opportunities arise (Walker and Sydneysmith 2008; Johnson and Welch 2009; Morrison and Termini 2016). As the distribution of target species changes, it is also important to adapt fisheries infrastructure and increase the flexibility of processing and supply chains for fisheries to reduce the impact on local fishing-based economies (Morrison and Termini 2016). Insuring fishers to provide stability in low income years and decrease ratcheting up and overfishing, analogous to crop insurance, could help to support fishing-based communities. Marine conservation tools such as MPAs can also be adapted to climate change by protecting both the current and future habitats of priority species, or by using dynamic reserves where the boundaries change over time (e.g., dynamic ocean management) (Hobday et al. 2013; Creighton et al. 2016). Fisheries management that promotes the adaptive capacity of target fish species and populations can also help to support fisheries adaptation. Specific examples include population-based fisheries management, which depends on understanding the genetic diversity of fish species and population distributions, to protect weak populations or populations on the edges of species distributions (Perry et al. 2010; Pinsky and Fogarty 2012). Fisheries management can also aim to protect fish population age structure to increase resilience to changing environmental conditions by using size limits, modifying fishing gear (e.g., net size and reducing post-release mortality of nontarget individuals; Morrison and Termini 2016).

In some cases, reactive management approaches may be suitable or successful given that predictive modeling of future environmental conditions and associated fisheries may be uncertain (Johnson and Welch 2009; Miller et al. 2010; Morrison and Termini 2016).

Reactive management approaches for fisheries and fishing-based communities include flexible and adaptive management systems that reward innovation, coordination, and collaboration between regions and management bodies. Increased monitoring and use of indicators can help to prepare managers and planners as conditions change and management needs shift, for example to manage dynamic spatial closures to adjust fishing activity based on real-time data on environmental conditions and fish distributions. Adjusting fisheries reference points to reflect changes in species or stock abundance depends on high-quality monitoring data of fisheries and environmental variability but would be effective in supporting fisheries abundance as target species ranges and abundance shifts (Botsford et al. 2009; Morrison and Termini 2016; Young et al. 2019). If species distributions or abundances have already changed, adjusting fisheries allocations can support adaptive fisheries management, but this depends on high-quality monitoring and modeling of species distributions and abundances and clearly defined allocation rules based on indicators of change (Young et al. 2019). Finally, adjusting fishing practices or fishing gear once fish communities change is also a reactive adaptation strategy. As fish species distributions and abundances change in response to climate impacts, fishers will adjust their fishing practices or gear to reduce interactions with nontarget stocks or protected species. This strategy can have negative tradeoffs based on economic costs and changes to social structure of communities (Johnson and Welch 2009; Young et al. 2019). It also depends on involving fishers early in management discussions (Yates 2014). First Nations may have fewer options for adaptation, especially given their dependence on marine resources for food security and cultural values (Walker and Sydneysmith 2008; Turner and Clifton 2009; Weatherdon et al. 2016b). In these cases, Indigenous knowledge may offer examples of adaptive strategies to enhance food security and thus community resilience in these systems. As an example, recent research on clam garden mariculture illuminated the historical importance of First Nations aquaculture on this coast (Pinkerton et al. 2014; Jackley et al. 2016). Learning from these traditional techniques may offer adaptive strategies for communities now and in the future.

Building adaptive capacity and resilience in remote communities is dependent on a variety of factors, including: (i) existing local and regional institutional capacity, (ii) local socio-economic development, (iii) infrastructure development and condition, and (iv) local experience with extreme weather events and other environmental or socioeconomic stress (Pelling and High 2005; Butler et al. 2015). Other factors that can contribute include social networks and cohesion, income diversification, and self-reliance (Walker and Sydneysmith 2008). However, current social and economic stressors are likely to reduce the capacity for remote communities to undertake or even consider climate change adaptation. Many coastal communities within the region already experience economic hardship and are limited in their capacity to undertake new initiatives or projects, even if the long-term benefits are relevant. Building on initiatives that are already in place to address environmental and economic changes and incorporating considerations of the impacts of climate change should be more effective for those communities (Walker and Sydneysmith 2008).

In BC, the provincial government has conducted vulnerability assessments for highway systems and continues to monitor sea level rise. The British Columbia Ministry of Transportation and Infrastructure is one of the first jurisdictions to require infrastructure design work for the ministry to include climate change implications. However, infrastructure operators in BC have primarily been responding reactively, rather than anticipating and proactively preparing for projected changes or impacts (Nyland and Nodelman 2017). This approach typically results in impacts being more costly or severe than if proactive adaptation actions had been taken (White and O’Hare 2014). 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 (Lemmen et al. 2016). 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 (Yumagulova and Vertinsky 2017). 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 (Withey et al. 2016). Regional models of sea level rise and seasonal climatic variability patterns would improve the ability of coastal managers to predict flood hazards and associated risk factors for the region.

Adaptive capacity building at the community level should be supported by national, regional, and sub-regional institutions and policies. Regional and sub-regional management should understand how local communities and local institutions function and are managed to support local adaptation actions and community resilience to major change. A transparent knowledge- and data-based climate change adaptation process can enhance existing adaptive capacities (Pelling 1997; Pelling and High 2005; Berke et al. 2008; Miller et al. 2010; Murphy 2014). Particularly, by empowering First Nations, socio-economic groups that may be already vulnerable can be included in decision-making processes (Green et al. 2006; Cutter et al. 2008). Especially for First Nations communities, past experiences with historical social, cultural, or economic changes can offer lessons for adapting to climate change. Key attributes of social adaptive capacity such as social capital and community networks are often already evident in place-based communities and community ties. However, climate change impacts and adaptation needs to be seen as relevant for present-day local community planning and management (Walker and Sydneysmith 2008; Reid et al. 2014). While attributes of resilience may exist inherently, the impacts of climate change challenge long-term adaptive capacities through rapidly rising sea levels and coastal storms, new impacts that threaten coastal communities who are dependent on vulnerable infrastructure and may lack essential relief services (Walker and Sydneysmith 2008). Additional financial support to cope with these increasing impacts, with land use planning that considers climate change, can improve the adaptive capacity of coastal communities.

To date, most climate change related adaptations documented in British Columbia have been reactive responses to unpredicted events, such as extreme forest fires or the mountain pine beetle epidemic (Parkins and MacKendrick 2007; Baynham and Stevens 2014; Government 2017). Planning for climate change seems to compete with a host of other priorities for the limited capacity of local and regional governance, as only one of the many stressors that affect the ecosystems, industries, and communities of British Columbia. For these reasons, cumulative impacts assessment (Halpern et al. 2008; Ban et al. 2010; Clarke et al. 2015a, 2015b) may be highly applicable for regional (and (or) sub-regional) adaptation planning. Proactive adaptation examples for coastal marine infrastructure include investments in early warning systems, particularly for storm surge related activities. Additional options include planning for emergency management, such as alternative routes for evacuations, identifying infrastructure under risk (roads, docks, rail routes, etc.), and programs to either mitigate impacts, or retreat and relocate if necessary.