Fifth National Climate Assessment
27. Northwest

In the Northwest, a history of disenfranchisement and systemic neglect of specific populations has influenced their geographic and occupational exposure to climate-related hazards.^59,60 Long-lasting effects of settler colonialism, racially restrictive covenants, and exclusionary laws have pushed Indigenous communities, communities of color, and low-income communities into areas that are more vulnerable to climate change.^59,61,62

Additionally, economic, political, and social systems play critical roles in distributing the costs and benefits of climate action (KM 20.3), limiting frontline communities’ socioeconomic mobility and, thus, their capacity to adapt. As a result, these communities not only experience disproportionate climate burden but also have the fewest resources with which to respond and adapt to climate change.⁵⁹

While many types of frontline communities exist—such as unhoused individuals, young children, older adults, and people with preexisting health conditions—this section highlights three communities: low-income urban communities of color, rural and natural resource–dependent communities, and Tribes and Indigenous communities.

Low-Income Urban Communities of Color

Redlining, restrictive housing covenants, and other historical policies have reinforced racial and economic discrimination and exacerbated inequitable exposure to contemporary climate impacts (KM 20.3).⁶³ Formerly redlined communities in Portland, Tacoma, Seattle, and Spokane are still economically and racially segregated and continue to be deprived of equitable access to environmental amenities that protect against the consequences of climate change.^64,65,66 Formerly redlined areas can be up to 13°F warmer than the city’s average surface temperature (KM 27.4), intensifying some impacts for residents such as heat exhaustion (Figure 27.2).^67,68 Incidences of heat-related illness and death are on the rise and are expected to increase as the climate changes.⁶⁹ Extreme heat poses the most consequential health risks for older adults, low-income households, outdoor laborers such as agricultural workers and construction workers, people who are unhoused, and others who have limited access to adaptive resources such as affordable cooling options (KM 27.5).

Previously redlined communities also have reduced diversity of plant and animal species due to land-use decisions that facilitated industrialization, reduced tree cover, and increased the severity of the urban heat island effect.^68,70,71 Furthermore, the same factors contributing to urban heat islands—a higher proportion of water-impervious surfaces and lack of green spaces—also increase the chances of urban flooding during extreme precipitation events.^72,73

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Economically and racially segregated urban communities are inequitably exposed to climate change impacts, including extreme heat.

Figure 27.2. The map shows satellite-derived land surface temperature (in °F) for July 14, 2017. Areas in Portland, Oregon, that were historically redlined—that is, areas that received Home Owners’ Loan Corporation (HOLC) grades of D, or “hazardous”—experience more intense heat island effects than areas that received HOLC grades of A or B. Residents are disproportionately exposed to extreme heat in these areas, where surface temperatures are up to 13°F warmer than the city’s average surface temperatures.⁶⁸ Figure credit: Portland State University and NOAA NCEI.

Rural and Natural Resource–Dependent Communities

Many rural communities depend on natural resources and therefore are particularly vulnerable to climate change (KM 27.3).⁷⁴ Workers in natural resource and outdoor-based industries will experience heightened exposure to heatwaves and wildfire smoke,^75,76 and outdoor construction workers face higher rates of traumatic injuries when exposed to extreme heat.⁷⁷ Washington and Oregon have high numbers of agricultural workers, especially Latino migrant workers, many of whom live in areas with low community resilience to climate-related hazards.

Structural inequities limit low-income, migrant, and agricultural workers’ access to clean air and drinking water, adequate living conditions, healthcare, and other social services, compromising their ability to adapt to climate-related risks.⁷⁸ As natural resource economies adapt, shifts in the seasonal availability of work and the diversification of local economies yield both positive and negative outcomes, including new economic opportunities, improved equitable occupational health and safety policies, and job security for outdoor workers and rural communities.^79,80,81 Weather- and climate-service providers supply these communities with tools and resources—such as communication materials or user-friendly models—to help them be more resilient.^82,83,84 Effective climate services that are inclusive of diverse perspectives and communities that also contextualize extreme weather events within long-term climate changes can reduce maladaptation and improve community resilience to climate change.^{3,74,85,86,87}

Tribes and Indigenous Communities

Tribes and Indigenous communities experience disproportionate climate impacts and systemic barriers that limit their ability to adapt to climate change (KM 16.1).^88,89 Due to historical policies of land allotment, many landscapes have heterogeneous management across Tribal and non-Tribal jurisdictions, which can amplify wildfire or flooding risk to Tribal structures and limit the adaptation options for Tribal members. These policies complicate the ability of Tribes to access structures and spiritual locations during or after climate-related events.^90,91 For example, some coastal Tribes, such as the Quinault Indian Nation, are adapting to coastal flooding by reacquiring fractionated land to relocate housing and key facilities.⁹² Even when Tribes manage contiguous areas of lands, limited access to funding, among other challenges, hinders planned or community-led relocation efforts (KM 9.3).^92,93

Climate change also affects cultural and traditional foods and other resources, leaving Tribes without traditional sustenance and medicines for religious or ceremonial purposes (KM 27.6).^94,95 Climate change can shift resources outside usual and accustomed areas into adjacent non-Tribal jurisdictions or cause phenological shifts that affect cultural harvesting practices.⁹⁵ For example, shifts are expected in huckleberry habitat and the timing of huckleberry flowering and fruit ripening, affecting Tribes who rely on huckleberries for cultural and economic uses.⁹⁶

Climate Action and Social Equity

Climate solutions designed without input from frontline communities can result in maladaptation, increasing vulnerability and cost burden.^97,98 For example, measures to lessen the impacts of extreme heat, like green infrastructure, have increased real estate values in cities such as Portland and Seattle, a phenomenon known as green gentrification.^59,99,100 As utilities transfer the costs related to extreme events and the transition to renewable energy directly to consumers, utility bills are expected to become unaffordable for low-income households.¹⁰¹ Inequitable adaptation exacerbates displacement risks for low-income urban populations and can lead to cascading development pressures in rural areas (KM 27.6).^102,103,104 The rising cost of living, alongside socioeconomic disparities, limits temporary relief and long-term recovery options for those who are affected by climate-intensified extreme weather events, such as the 2021 heat dome event.

In response to grassroots advocacy and community-led efforts, state and local climate policies in the Northwest are increasingly recognizing the importance of climate justice. These policies are prioritizing strategies such as subsidizing adaptation, redistributing benefits, and reducing harm to frontline communities.^105,106 Despite facing disproportionate risks from climate change impacts, frontline communities have emerged as leaders in climate action, elevating policies that center social equity and confer resilience to communities across the region.⁹⁷

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Ecological Effects of Climate Trends and Extreme Events

Long-term changes in climate and the frequency and magnitude of extreme events, such as droughts, floods, and heatwaves, affect species and ecological processes (Figure 27.3).^{107,108,109,110} High temperature records set in the Northwest from 2015 through 2021 were associated with many short-term or long-term ecological transformations, such as mortality or physiological damage to numerous native species of plants and animals, changes in water availability, and wildfire dynamics. Ecological effects and responses to climate change are not uniform, even among closely related species.^111,112

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Long-term climate changes and extreme events threaten Northwest ecosystems.

Figure 27.3. (top) Flooding on November 16, 2021, in the Nooksack River is shown. Flooding is expected to become more frequent and severe as a result of more intense rainfall and rain-on-snow events. (middle left) Non-native invasives such as the European green crab (Carcinus maenas) disrupt food webs as their distribution expands with warming coastal waters. (middle center) Postfire debris flows are expected to become more common with increased wildfire and precipitation intensity. (middle right) Large areas across the Northwest—such as in Idaho—are prone to increased risk of wildfires. (bottom left) Aspen is sensitive to high air temperature, leading to more dying aspen groves. (bottom center) Increases in the distribution and density of non-native invasive grasses, such as cheatgrass (Bromus tectorum), exacerbate wildfire risk. (bottom right) Seedlings are more sensitive than mature trees to heat stress and drought. Satellite image: (top) Lauren Dauphin and Joshua Stevens, NASA Earth Observatory. Photo credits: (middle left) ©Emily Grason; (middle center, middle right, bottom left) ©Charlie Luce; (bottom center) ©Erica Fleishman; and (bottom right) Colorado State Forest Service.

Terrestrial Ecosystems

People in the Northwest rely on forests for diverse goods, services, and cultural purposes (KMs 7.2, 27.2). Warming temperatures and decreased summer precipitation over the past four decades have contributed to increases in the size and maximum elevation of wildfires in Northwest forests, and those trends are expected to continue.^113,114,115 Because concurrent heat and drought are becoming more common,¹¹⁶ the volume of stressed or dead vegetation is increasing, which is increasing fuel load and wildfire risk. Across the western United States, many previously burned forests are reburning.¹¹⁷ Some low-elevation and dry areas are converting from forest to shrubland after wildfires, and these transitions are expected to continue in the Northwest.^118,119

In arid woodlands and shrublands throughout the Northwest, the distribution and abundance of non-native and highly flammable cheatgrass (Bromus tectorum) continue to increase before and after wildfires.^120,121 Cheatgrass establishment is associated with relatively high precipitation during autumn and spring¹²⁰ and with ground disturbance from wildfire, livestock grazing, and other types of land uses.^121,122 Changes in human activities such as recreation, development, transportation routing, and energy transmission will also continue to affect wildfire frequency (KM 27.4).¹⁰⁴ The length of the wildfire season and the potential for human-caused ignitions in all Northwest ecosystems are expected to increase as drought frequency, duration, and intensity increase.¹²³

Art × Climate

Lisa Harrington
A Vision of Fire
(2023, digital)

Artist’s statement: This piece, 'A Vision of Fire,' was created with several layered and manipulated photographs, the key one being a photo of healthy forest in Oregon in 2018. By layering it over flame and dust-colored photos, a view of the potential fate of the forest was achieved. This work follows several years of drought and catastrophic fire in the Pacific Northwest. It also follows my career as a geography professor, where I focused on human-environment relations, climate change, and rurality. This work connects such academic views with imagination and emotion.

View the full Art × Climate gallery.

Artworks and artists’ statements are not official Assessment products.

Climate change can affect the distribution and population dynamics of native and non-native species. When some non-native species become effective competitors with native and other non-native species, they are considered to be invasive in natural and human-dominated systems, including forests used for timber harvest or recreation. Some of these invasive species are expected to become more prevalent in response to projected increases in temperature, especially minimum winter temperature, and increases in the frequency, duration, and severity of drought across the Northwest.^117,124

Additionally, some insects in the Northwest that harm or kill conifers are native herbivores that are prone to outbreaks. For example, densities of native mountain pine beetles (Dendroctonus ponderosae) generally are low, but outbreaks can result in 60% stand-level mortality over vast forest areas.¹²⁵ The Douglas-fir beetle (Dendroctonus pseudotsugae), another insect native to the Northwest, can damage both stressed and healthy Douglas firs (Pseudotsuga menziesii). The effects of outbreaks on trees generally are greatest during hot, dry summers when trees may be water-stressed.¹²⁶ Additionally, warm winters may decrease beetle mortality, increasing the likelihood of an eruption.^126,127

Aquatic Ecosystems

Hydrological and thermal changes will prompt shifts in species composition of native and non-native fishes, especially where their habitats have been impaired by land use, including stream modifications and water withdrawals.^{128,129,130,131} For example, rising temperatures, disease spread, and competition threaten the native bull trout (Salvelinus confluentus) and cutthroat trout (Oncorhynchus clarkii).¹³² Non-native invasive species such as smallmouth bass (Micropterus dolomieu), which thrive in warmer waters, continue to expand in the Columbia River basin, competing with and consuming native salmonids.^133,134 Increased intensity of precipitation and occurrence of rain-on-snow events will increase flood severity and frequency, endangering salmon eggs and juveniles.^{135,136,137,138,139}

Increases in wildfire size and intensity are expected to lead to local extinctions of resident fishes,¹⁴⁰ warmer stream temperatures,¹⁴¹ and increased sediment transport, turbidity, and fine sediments in streambeds.^142,143 Habitat connectivity can ameliorate local extinctions following wildfire and postfire debris flows, although local extinction can be permanent if habitat patches are small and are isolated by temperature or road culverts.¹⁴⁴

Coastal and Marine Ecosystems

The 2014–2016 marine heatwave had numerous effects in the highly productive California Current marine ecosystem,^145,146,147 including the first documented domoic acid poisoning of sea lions, with detectable levels of domoic acid in dolphins, whales, and seals off the Washington coast.¹⁴⁸ These toxins are now detectable year-round in sea lions, not just during algal blooms.¹⁴⁹ Changes in the ecosystem during the heatwave also caused mass mortality of seabirds, such as Cassin's auklets (Ptychoramphus aleuticus)⁴⁸ and common murres (Uria aalge)¹⁵⁰ and led to extensive closures of crab and shellfish fisheries.⁵⁴ Many salmon populations also contracted sharply after the heatwave.¹⁵¹ Preliminary evidence indicates that, following extreme heat in June 2021, numerous shellfish species became thermally stressed or died.¹⁵² The frequency and intensity of marine heatwaves are expected to increase.¹⁵³ These marine heatwaves are expected to have broad-ranging impacts on marine ecosystems¹⁵⁴ and increase the incidence of human–wildlife conflict, such as entanglement of whales in fishing gear.¹⁵⁵ While the impacts of future marine heatwaves on species will vary—some species will decline, others will increase, and others will shift their distributions—current regulations and practices may not adequately respond to these impacts, potentially leading to disruptions in fisheries (KM 27.3).¹⁴⁵

Salmon abundance, age at maturation, and size at maturity are widely correlated with climate trends (Figure 27.4).^{156,157,158,159} Idaho’s Snake River spring and summer Chinook and sockeye salmon are at particularly high risk across multiple future temperature scenarios (Box 27.1).^{160,161,162,163,164,165} Increasing temperatures are expected to increase the duration and spatial extent of enabling conditions for harmful algal blooms,^166,167 increasing threats to marine mammals, fish, and shellfish. Population instability increases volatility in fisheries and the extinction risk for species that are already at low abundance.^168,169

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Stressors stemming from interactions between human activities and natural systems affect freshwater and marine ecosystems and reduce salmon resilience to climate change.

Figure 27.4. Human activities and climate change alter the physical environment in concert, often amplifying their impacts through cumulative effects over the salmon life cycle. They also directly and indirectly alter freshwater and marine systems. Natural systems respond to changes in their environment through both evolutionary and ecological processes. The sum of these many different processes has led to declines in many populations of salmon over decades and reduced their ability to cope with future climate change. Figure credit: NOAA Fisheries.

Ability of Ecosystems and Species to Adapt to Climate Change

Historic and contemporary land use interacts with climate change to affect species’ adaptive capacity—their genetic, physical, and behavioral ability to respond to environmental change.^186,187 Many different strategies to adapt and build resilience within Northwest ecosystems include ecological protection and management, assisted migration, market-based mechanisms, and conservation of genetic diversity.^188,189,190

Protection and restoration of natural water bodies and processes that maintain water availability and quality can offset some effects of land use, including the growing demand for irrigation that reduces streamflow and freshwater habitat quality.¹⁶ Similarly, modification of natural or built flood-control structures can reduce adverse downstream effects of changes in hydrology, sedimentation, and shoreline erosion and improve water quality and capacity for groundwater drainage in agricultural systems.¹⁹¹ These efforts can lead to cascading benefits for habitats, supporting salmonids, other fishes, shellfish, and shorebirds.^192,193

Restoration of floodplains that provide habitat for salmon¹⁹⁴ also benefits humans by reducing the current and future exposure of agriculture and infrastructure to flooding from the combined effects of higher sea levels, storm surge, and stream runoff.^195,196 As several dams and other barriers to historical spawning areas have been removed in recent decades, fishes have rapidly recolonized newly accessible habitat in some cases.^{197,198,199,200}

Reintroduction of fire and thinning of non-fire-resistant vegetation reduce wildfire severity and risk in some Northwest forests and woodlands, especially dry forest types where vegetation has accumulated due to past fire exclusion policies.^201,202 These forest management practices also have the potential to reduce drought-related mortality.²⁰³ Burning and forest thinning may not decrease wildfire severity and risks in wet or cold forest types^204,205 but can increase plant and animal diversity.

Wetlands offer some protection against extreme weather events.²⁰⁶ Wetland mitigation banks create or enhance wetlands in a given location as compensation for loss or degradation of other wetlands. The number of these banks has increased across the region,²⁰⁷ but long-term evaluations of created wetlands²⁰⁸ or the effectiveness of wetland mitigation banks²⁰⁹ are uncommon. Market-based approaches, such as temporary water-right leases or permanent transfers, have the potential to support ecosystem functions, such as instream flow augmentation for fish health, with payments to users of competing resources.²¹⁰ However, market and political bottlenecks affect the efficacy of these approaches.²¹¹

The ability of species to adapt to climate change is varied, and the likelihood of adaptation depends in part on the amount of genetic variation in a population or species, which is often related to the number of individuals and their relatedness.¹⁸⁸ Evolutionary responses to recent climate change have generally been less than what might be expected, and these constraints are not fully understood.^212,213 The feasibility of quantifying abundance, relatedness, and genetic variation varies among populations and species, and these measures have not been estimated for many populations and species.

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Agricultural Industries and Livelihoods

The Northwest encompasses 138.8 million acres of public and private cropland, grassland, pasture, rangeland, and forests,²¹⁴ and agricultural production totaled $6.28 billion in 2021 (in 2021 dollars).²¹⁵ The agricultural economy includes farms and ranches that have been in operation for multiple generations and is dependent on a seasonal migrant workforce, mostly from Mexico and Central America (KM 27.1).

Climate change affects crop production quantity and quality, and multiple competing effects depend on crop and region, causing increases and decreases in projected yields (Box 27.2; KM 11.1).²¹⁶ Chill accumulation—exposure to cold temperatures during dormancy—is key for fruit set and fruit quality in perennial crops and is expected to decrease in the southern parts of the Northwest and increase in the northern parts.²¹⁷ Increased exposure to extreme temperatures can induce cosmetic effects (e.g., sunburn in apples) that make crops increasingly unmarketable.²¹⁸ Pest pressures are expected to increase due to climate change; however, preliminary research indicates that the efficacy of non-chemical control of pests can also increase, providing opportunities for reduced pesticide use and environmental benefits.²¹⁷ Warmer autumns have been linked to potential increased risk of honeybee (Apis mellifera) colony failure in the following spring even in the absence of other stressors,^219,220 thereby affecting the specialty crop industry that relies on managed honeybees. While increasing temperatures in some regions may present new economic opportunities, such as winegrape growing in Puget Sound,²²¹ other climate-related impacts such as wildfire smoke may impede these emerging industries.²²²

Drought conditions have also affected the region’s agricultural lands and rangelands. Across the region, the 2021 drought resulted in reduced access to irrigation water and yield loss for several crops.²²³ Significant yield declines between 2020 and 2021 in winter wheat, spring wheat, and barley were also attributed to drought.²²⁴ Droughts have also decreased forage availability and productivity, affecting livestock operations and management of habitat for other species.²²⁵ Market approaches such as temporary leasing of water can alleviate drought impacts on agricultural productivity and the regional economy to a certain extent.²²⁶ Similarly, grass banks, which allow landowners to lease forage space for ranchers in exchange for implementation of conservation projects by ranchers, can allow ranchers to better manage forage shortages caused by drought and are gaining popularity in the western United States.^227,228

Increasing trends in crop insurance loss payments—an indicator associated with economic disruption of agricultural production due to extreme events and impacts—reflect the region’s warming temperatures and declining snowpack (Figure 27.5).^229,230 Agricultural producer perceptions of climate risk affect the efficacy of place-based adaptation and resilience efforts, and operations that adapt to extreme weather and changing climate conditions may see improved productivity and resilience (KMs 6.1, 27.1).^{3,82,83,87,231}

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Increasing trends in crop insurance loss payments reflect the economic disruption of agricultural production due to extreme events including droughts.

Figure 27.5. These county-level maps compare all crop insurance indemnity payments from the US Department of Agriculture Risk Management Agency (left) with those specifically due to drought, from 2006 through 2020 (right). All indemnity payments reflect both biophysical and socioeconomic impacts from weather- and climate-driven events, including major droughts, on important commodities such as wheat and potatoes. Figure credit: USDA. See figure metadata for additional contributors.

Forest Industries and Livelihoods

Northwest forests provide multiple ecosystem and economic services. Rising temperatures and increased frequency of ecological disturbances may affect forest structure and growth (KM 27.2),²³² leading to reductions in the quantity and quality of forest products and commercially important timber species.^{233,234,235,236} For example, these impacts could lead to the increase in density and distribution of ponderosa pine at higher elevations in the Blue Mountains ecoregion and the expansion of western Cascade Range Douglas fir into higher elevations, affecting timber supply and carbon sequestration potential.^234,237,238 Dry coniferous forests and woodlands in lower to middle elevations—such as those on the east side of the Cascade Range, the Palouse Prairie–forest ecotone in Idaho, and drier areas of the Rocky Mountains—will experience large increases in wildfire frequency, extent, and severity, threatening forest and timber management initiatives.^117,239,240

Climate impacts to forest industries will affect the livelihoods of communities dependent on timber and non-timber forest products.^234,237 While rural timber-based economies face additional economic risks from wildfires and drought, they also have local knowledge and insight to effectively reduce some of these risks (KM 27.1).²⁴¹ Despite this, climate impacts to forest product industries can lead to economic depression within some communities, resulting in migration away from these communities (KM 27.6).²⁴¹ However, localized species shifts could induce industries and private landowners to make new financially beneficial adaptation choices.^235,242 Other emerging opportunities, such as cross-laminated timber, can support local timber economies while providing sustainable and less carbon-intensive alternatives for construction.²⁴³

Reforestation and afforestation are expected to benefit ecosystem functions, such as increasing water quality, long-term carbon storage capacity, and viability of some native species (KM 7.2).²⁴⁴ Tribal forest enterprises use harvest and conservation techniques reliant on Indigenous value systems to support improved forest management.²⁴⁵ For example, the Confederated Tribes of the Colville Reservation are employing innovative drone technologies to conduct forest inventories, enabling them to improve their forest and timber management efforts, air and water quality, wildlife habitat, preservation of cultural areas and practices, and carbon sequestration potential.²⁴⁶

Commercial Fisheries and Livelihoods

Climate change has affected fisheries in the Northwest (KMs 27.2, 10.2). Marine heatwaves and harmful algal blooms have led to climate-induced fishery losses on the West Coast, accounting for a $641.1 million (in 2022 dollars) reduction in commercial fishing revenue.²⁴⁷ Climate change can also intensify stressors such as decreasing catch and landing rates and accelerating the graying of the fleet phenomenon—the increasing average age of commercial fishers.^248,249 Fishery losses and closures can affect fishing-adjacent industries, such as hospitality, and the cultural identity of residents who directly or indirectly rely on fishing.²⁵⁰

Tribes account for over half of federal fishery loss requests.²⁴⁷ Further population declines, especially of Pacific salmon, will have additional consequences for Tribal communities reliant on fish for subsistence, ceremonies, and health.^95,251 Ocean acidification, hypoxia events, and algal blooms are also hurting Tribal Dungeness crab fisheries.²⁵² It is not always feasible for Tribes to secure loans and equipment and to thrive in competitive market systems. However, many Tribes are utilizing Indigenous approaches and Tribal–federal partnerships to increase the resilience of their commercial and subsistence fisheries.²⁵³

Tourism, Recreation, and Customer Service Industries

The outdoor tourism and recreation industry in the Northwest supports $51.9 billion (in 2022 dollars) in annual expenditures and employs more than 588,000 individuals.²⁵⁴ The economic impacts of climate change on the recreation industry will vary.⁷⁹ The snow season is projected to decrease by nearly half by the end of the century in parts of the Cascade Range.²⁵⁵ Snow-based recreational industries such as skiing have already lost revenue due to the decrease in snow days, and future impacts to snowpack are expected to further harm snow-based recreational industries.^256,257 In contrast, earlier spring snowmelt and increasing temperatures can increase access to hiking trails and campgrounds, thereby extending these seasons. However, a regional shift from a snow- to a rain-dominated system (KM 27.6)^16,258 may present new operational and maintenance challenges from increased flooding and erosion.²⁵⁹ Recently burned areas typically are closed as a safety precaution, and poor air quality from wildfire smoke can deter outdoor activities and recreation.^79,260

Higher temperatures may increase the demand for water-based and warm-weather activities such as boating, cycling, and fishing (KM 27.6).^79,261 For example, economic gains for cycling activities in Washington are expected to increase due to the declining numbers of cold days.²⁶² However, climate change can reduce the quality and aesthetics of recreational sites, affecting user preference and leading to reduced visitation rates.⁷⁹

Changes in recreation management may produce inequitable outcomes. Rising costs to access recreation sites and limited ability to travel to alternative destinations will disproportionately affect low-income visitors. Increased cost of living in high-amenity areas such as ski resort towns will also stress workers and adjacent communities (KM 27.6).²⁶³ Outdoor activities such as skiing and hiking can improve overall health and thereby reduce healthcare costs; however, decreased access to such activities can lead to increased risk of chronic diseases, mental health impacts, and loss of cultural heritage and connection to place (KM 27.6).²⁶⁴

Just Transition and Community Livelihoods

As local economies in the Northwest shift to low-carbon industries and climate-adaptive practices, historically overburdened workers will face higher exposure to climate-related hazards as well as risks of being excluded from economic shifts to a green economy (KM 27.1).^76,97,269 Local governments, Tribes, labor unions, and community groups across the region are evaluating and adopting policies and programs that support a just transition (KM 20.3).⁹⁷ Efforts toward a just transition in the Northwest region include investments in low-carbon sectors, local economic diversification plans, training and skills development for workers in resource-dependent and fossil fuel–dependent industries, financial assistance for impacted communities, and worker protections.^270,271 Despite progress in specific sectors, efforts that account for historically overburdened workers can reduce potential livelihood disruptions caused by economic shifts associated with decarbonization.^97,272

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Infrastructure systems are threatened by extreme events such as drought, wildfire, heatwaves, floods, and landslides (KM 12.2).²⁷³ Climate change has revealed vulnerabilities in infrastructure planning and design, which are typically based on historical conditions and do not account for recent increases in the frequency or severity of extreme events. Isolated communities and those without alternatives if infrastructure fails are among the most vulnerable. Designing resilient infrastructure requires accounting for interdependencies among the built environment’s physical and social elements.^274,275,276

Water Infrastructure

Droughts in the last decade in the Northwest demonstrated water supply vulnerabilities, such as depletion of reservoirs across central and eastern Oregon and southern Idaho.^277,278 Some water sources, infrastructure, and operations that treat and convey water were resilient during these droughts. However, some water providers were forced to access alternative sources, institute mandatory or voluntary conservation measures, or otherwise modify their operations. Small rural water providers are vulnerable because they usually depend on a single water source or sources with limited capacity and because operators generally have limited resources for planning, upgrades, and emergency response (KM 27.1). Wildfires in 2020 and 2021 damaged physical elements of the water delivery and treatment systems, disrupted electricity systems, and increased the amount of sediment in waterways and reservoirs.^142,279 These vulnerabilities will increase as droughts and wildfires become more frequent and severe.

About 30% of Northwest households use septic systems to treat their wastewater.²⁸⁰ Sea level rise, high temperatures, extreme precipitation, and high streamflows reduce the function of septic systems.^281,282 For example, saturated soils impede wastewater treatment in drainfields.²⁸³ Failures of wastewater storage and treatment will negatively affect human health and increase nitrogen loads in waterways.²⁸⁴

Emerging data and technologies can make drinking water and stormwater systems more resilient to climate change. For example, projections of changes in storm duration, intensity, and frequency²⁸⁵ provide information needed to upgrade stormwater systems to reduce stresses from extreme precipitation.^286,287 Water utilities can reduce water losses during delivery and alleviate stress to the system during hotter summers and more severe droughts by upgrading distribution lines and minimizing water losses during treatment.²⁸⁸ Water-efficient appliances, sprinklers with soil moisture sensors, drought resilient plants, and conservation education and incentives can also reduce water demand.²⁸⁸

Energy Infrastructure

Climate change impacts nearly every aspect of the energy system, with interdependencies and cascading effects in other critical sectors (KMs 5.1, 12.2, 31.1; Focus on Compound Events). For instance, less snow, earlier snowmelt, and more frequent and intense droughts will alter the seasonal capacity of hydropower, a primary source of regional energy, to meet electricity demand.^{278,289,290,291} Earlier snowmelt is also increasing the need for water storage in Idaho reservoirs.¹¹ Removal of dams may support salmon recovery but can reduce resilience in the regional power system (Box 27.1).²⁹²

Increasing temperatures and heatwaves are shifting the seasonal timing and spatial footprint of electricity demand.^291,293 Cooling degree days, a metric associated with energy demand for cooling, are increasing across the Northwest, and the region’s population increases will also affect the electricity demand, potentially leading to energy shortfalls (Figure 27.6).²⁹⁴ Population growth and droughts are expected to amplify competing claims to the water supply by irrigators, Tribes, power plants, and other water rights holders,^295,296 highlighting the interdependencies of energy, water, and agricultural systems. Strategies such as demand-side management (voluntarily shifts in power loads) and ongoing additions of solar power, such as that being pursued by the Nez Perce Tribe,²⁹⁷ can increase the resilience of energy infrastructure.

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Hydropower generation is currently meeting the number of cooling degree days but might not continue to do so as temperatures and heatwaves increase in the future.

Figure 27.6. Cooling degree days—the annual cumulative number of days on which the average temperature is greater than 65°F—are typically used to measure cooling energy demand. During 1990–2020, the annual number of cooling degree days (orange lines) increased, whereas annual hydropower generation (in millions of megawatt-hours, gray bars) decreased slightly. Hydropower generation may not meet projected future cooling demand, especially during summer. Figure credit: Boise State University and Cascadia Consulting Group.

Electricity transmission and distribution grids are both a source of wildfire risk and are also at risk from wildfire, particularly in hot, dry, and windy conditions. Electric utilities and land management agencies are evaluating potential actions that they can take to reduce future wildfire risk and impacts on electricity systems (Box 27.3). Some Northwest electric utilities are exercising public safety power shutoffs or “fast trip” programs that trigger outages when faults are detected.²⁹⁸ Such shutoffs can reduce the likelihood of ignitions from the electric grid when complemented by other risk-mitigation measures but can also negatively affect local economies and human health (Focus on Western Wildfires). Risks to electric grid infrastructure from wildfires may also be higher in remote areas, as monitoring capacity is less robust.

Carbon emissions have been increasing on an absolute basis in the Northwest (Figure 27.7). The shift to low-carbon energy systems can be complex, and there are varied trade-offs and co-benefits between technological innovations that can enhance the viability of clean energy sources and increase the resilience of both infrastructure systems and the communities and industries dependent on them (KM 5.3).^300,301

Transitions to low-carbon energy may be perceived as requiring substantial time to accomplish, yet research has shown that considerable low-carbon transitions can occur in less than 15 years.³⁰² Considering these conditions, states, local governments, and utilities have begun to develop low-carbon and decarbonization plans and pathways. Oregon passed legislation to eliminate carbon emissions from the power grid by 2040, and Washington passed legislation to reduce carbon emissions by 95% from 1990 levels by 2050. In Idaho, cities such as Boise and utilities such as Idaho Power have carbon reduction plans.^105,303 Agencies and utilities are utilizing diverse strategies including energy conservation and efficiency investments; design approaches such as buildings with southern-facing windows to reduce cooling needs; harnessing renewable gas from farms and municipal landfills; and exploring and utilizing alternative energy sources while investing in decarbonization technologies.^{300,304,305,306}

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Carbon dioxide emissions from fossil fuel consumption vary widely by sector and state.

Figure 27.7. These graphs show carbon dioxide (CO₂) emissions (in millions of metric tons) from fossil fuel consumption by state (top) and sector (bottom). Carbon dioxide emissions from fossil fuel consumption are greatest in Washington, followed by Oregon and Idaho. Transportation emits more CO₂ than other sectors across Idaho, Oregon, and Washington. Figure credit: Boise State University and Cascadia Consulting Group.

Transportation Infrastructure

Atmospheric rivers in 2021 illustrated existing understanding of how landslides and flooding can disrupt transportation routes.^307,308 The disruption of transportation routes can lead to injury or death due to a lack of evacuation routes and cutoff from critical emergency services, healthcare, and other goods and services.^29,309 In extreme cases, the loss of transportation routes and social services may displace households and reduce regional labor supply.³¹⁰ Much of the Northwest’s transportation infrastructure, such as railroads, bridges, and highways, is aging and thereby increasing vulnerability to climate-related hazards. For example, the average age of all surveyed bridges in Oregon is 46 years old, and the typical design life is 75 years.³¹¹ Some state transportation agencies, such as Washington State Department of Transportation and Oregon Department of Transportation, have assessed climate risks to their routes and highways and various adaptation options (KM 13.1).^312,313

Transportation is the largest source of greenhouse gas emissions in the Northwest (Figure 27.7), and utilities and transportation agencies across the region are exploring electrification options to reduce emissions. However, efforts to electrify the transportation sector will increase electricity demand and place additional stress on the regional energy system (KM 13.1).^314,315,316 Electric vehicles’ energy efficiency and electricity sources will affect the potential magnitude of reduction in transportation-related emissions (KM 13.4).^314,316

Housing and Land Use

The majority of the land in urban areas is devoted to residential housing, which provides shelter to people during extreme events but can also exacerbate exposure to harmful impacts. The specific location of urban housing structures can directly affect the severity of local climate impacts. Urban areas are warmer than their surrounding landscapes, a phenomenon known as the urban heat island effect, and some urban neighborhoods can experience temperatures upwards of 13°F warmer than other areas of the same city (KMs 27.1, 12.2). Residential density in urban areas is increasing more in historically lower-income neighborhoods, reducing the availability of green space and increasing the extent of impervious surfaces, thereby worsening heat island effects.^68,100 Urban trees and other vegetation could provide shade, but there are trade-offs between mitigating heat islands and conserving water.³¹⁷ Creating incentives or requirements for water-efficient landscaping (xeriscaping) while also providing shade and stormwater absorption could help reduce adverse impacts from extreme heat and storms.

Similarly, the location of housing beyond urban centers also interacts with the impacts from climate change. For example, housing in the wildland–urban interface (WUI)—or locations where wildland vegetation and houses meet—has increased over the past several decades and increases the risk of wildfire impacts on housing structures (KM 27.6).^102,318

Furthermore, the quality of materials and types of amenities in both urban and rural housing design and construction affect exposure to some impacts, such as wildfire smoke. Households with access to HVAC and air filtration systems can improve indoor air quality and reduce wildfire smoke exposure;^319,320 however, they may be insufficient to mitigate anticipated increases in the number of wildfire smoke days and associated high concentrations of fine particulate matter and other pollutants.^321,322

Climate change will also affect digital infrastructure, such as internet infrastructure systems. For example, fiber conduits and nodes in the greater Seattle area are at risk of inundation from sea level rise by the 2030s,³²³ jeopardizing telecommuting strategies that some jurisdictions are using to reduce vehicle-miles traveled by employees and associated transportation-related emissions.

Because land-use laws determine how human activity is distributed in space and how infrastructure is built, they affect mitigation of and adaptation to climate change.³²⁴ While each state has a different set of land-use policies, state-level land-use planning guidelines can limit or expand opportunities for local land-use plans to respond to climate change (KMs 6.2, 12.3). Nevertheless, land-use laws and policies can facilitate adaptation in multiple ways, including protection (protecting existing structures from climate-related hazards via engineered structures), accommodation (continued use in hazardous locations, like flood zones, by improving design or development standards such as raising foundations or creating natural floodplains), or retreat (restricting new development in hazardous locations).^{324,325,326,327}

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Multiple public health challenges have been associated with climate change. Those whose livelihoods are dependent on the weather—like outdoor day laborers and wildland firefighters—and people with preexisting health conditions and limited coping capacities face some of the gravest challenges (KM 15.1). COVID-19 has overextended the public health sector since 2020 and strained traditional approaches to reducing public health impacts from climate-induced disasters (such as cooling or warming shelters), because convening groups in large areas has been prohibited or limited (Focus on COVID-19 and Climate Change).

Physical Health Impacts of Climate Change

Climate change amplifies health risks, especially for those with underlying health conditions, and leads to physical health impacts such as premature mortality from heatwaves, compromised respiratory health due to wildfire smoke, infectious and vector-borne diseases, exposure to mold and environmental health hazards, diseases in some foods and natural resources such as shellfish toxins (KMs 27.2, 27.6), and exposure to toxicants (KM 15.1). Heatwaves and extreme heat, which are increasing in frequency and intensity, kill more people annually than any other natural hazard.^328,329 Increasing frequency of wildfires will increase the number of poor air quality days.⁷⁵ Together, heat and wildfire smoke have caused thousands of deaths in the Northwest since 2018. The greatest number of deaths occurred in summer 2021 (Figure 27.8)³³⁰ when almost a thousand people perished during an extraordinary heatwave that was partially attributed to climate change.^331,332 Although it is unknown whether events such as the 2021 heat dome are an anomaly or will become increasingly frequent in the Northwest,³³³ future heat-related morbidity and mortality across the Northwest are expected to increase across all scenarios.^69,334 Many of these deaths were preventable and happened because communities were maladapted to the level of heat, which disproportionately affected women, people of color, and people with chronic illnesses and placed additional strain on the Northwest’s healthcare system.^69,330

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Heatwaves, such as the heat dome event in the summer of 2021, place strains on healthcare systems.

Figure 27.8. The graph shows the number of heat-related emergency department visits for US Department of Health and Human Services (HHS) Region 10 (which includes Alaska, Oregon, Idaho, and Washington), relative to the rest of the country, from May 1–June 30 in 2019 and 2021. There was a sharp increase in emergency department visits for heat-related illness during the 2021 heat dome event in HHS Region 10, relative to the heat-related emergency department visits for the region in 2019. HHS Region 10 also experienced relatively more heat-related emergency department visits during the 2021 heat dome event compared to the rest of the country over the same time period. Adapted from Schramm et al. 2021.³³⁵

Wildfire smoke can be severe in the region, particularly in highly populated areas, Idaho, and eastern Washington and Oregon.^321,336 In the western US, smoke events from 2004 through 2009 were associated with a 7.2% increase in respiratory hospital admissions among adults over 65, compared to the previous decade. In Washington, smoke-related mortality increased during the 2020 wildfire season, when the ambient total particulate matter concentration changed from near zero to 100 micrograms per cubic meter (µg/m³) over the course of a summer.³²² Increased particulate matter (PM_2.5) due to wildfire smoke in the West has been associated with a predisposition to COVID-19 and higher COVID-19 case rates and mortality.³³⁷ Future wildfire seasons—and increases in PM_2.5 associated with those wildfire seasons—is projected to increase excess asthma incidences by the 2050s under a very high scenario (RCP8.5; Figure 27.9); Washington, Oregon, and Idaho are expected to see an increase of 25.7, 41.9, and 29.4 wildfire smoke–related emergency department visits per 10,000 persons, respectively.³³⁶ The anticipated financial burden of healthcare costs associated with wildfire smoke exposure is expected to significantly increase across the Northwest.^336,338,339

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Excess asthma burden associated with wildfire smoke is expected to disproportionately affect the Northwest.

Figure 27.9. Northern Idaho, coastal Oregon, and southwest Washington are expected to face some of the highest wildfire smoke–related asthma burden in the Northwest. Excess asthma incidences related to wildfire smoke are expected to increase across the Northwest. The figure shows the average expected total number of excess asthma events per 10,000 people per wildfire season by the 2050s under a very high scenario (RCP8.5). Adapted from Stowell et al. 2022³³⁶ [CC BY 4.0].

Additional health-related impacts are associated with heatwaves and wildfire smoke.³⁴⁰ Lower birth weight and premature birth are attributed to these events,^341,342 although empirical evidence from the Northwest is still emerging. Similarly, evidence of an association between repeated long-term exposure to wildfire smoke and cancer incidence is emerging.³⁴³

People with access to air-conditioners or air purifiers, along with the financial capacity to operate these systems, will fare better than those whose homes are poorly insulated and allow for a greater concentration of ambient pollutants to enter indoor spaces. Young children and older adults are particularly vulnerable, as are those who live in trailer parks, recreational vehicles, or historically disinvested urban areas. Discriminatory policies such as redlining also contribute to greater exposure to heat and other climate-induced events, such as urban flooding (KM 27.1).

Mental Health Impacts and Climate Change

Each extreme event has its own set of observed mental health consequences, including some overlapping disorders such as post-traumatic stress, anxiety, depression, and suicide.^344,345 Negative mental health outcomes have been observed before and after a climate-related extreme event.³⁴⁶ For example, wildfire smoke can limit outdoor activities, reducing individuals’ ability to exercise, recreate, and relieve stress, leading to additional mental health consequences (KM 27.6). Mental health consequences of climate change may resolve quickly; however, long-term impacts can be delayed and, in the case of post-traumatic stress, can even affect future generations.^347,348

Idaho, Oregon, and Washington have a higher prevalence of mental illness relative to the rest of the country.³⁴⁹ The mental health impacts of climate change will continue to be uneven. Youth concerned about climate change, Tribal communities losing cultural resources at a rapid pace, and houseless individuals who experience increased exposures to climate change have a higher prevalence of climate-related mental illnesses compared to other populations.^{345,350,351,352}

Community Health and Well-Being Impacts

Climate change impacts community health and well-being in many ways. Increased temperatures are associated with an increase in violence and self-harm, including suicide.^344,353 The magnitude and duration of droughts in the Northwest are projected to increase and potentially disrupt agricultural production and exacerbate food insecurity,³⁵⁴ which can cause psychological distress.³⁵⁵ Extreme events will continue to disrupt medical care and services, and injury and illness from such events are expected to exceed the capacity of the healthcare system. Strengthening community and social cohesion can improve community health outcomes and increase preparedness for disasters and extreme events.^356,357

Tribal Well-Being Impacts

Climate change is disrupting Tribal communities’ access to traditional foods, compounding legacy effects of settler colonialism that have led to increased consumption of processed foods, which is associated with higher rates of diabetes, heart disease, and obesity for Tribal communities.^358,359,360 Algal blooms have contaminated shellfish to the point that they cannot be consumed during traditional seasons (KM 27.2). Increasing temperatures have created more favorable conditions for transmission of parasitic and invasive species among food sources such as deer and fish.^361,362 The continued effects of climate change on the phenology of important species and access to cultural resources are expected to disrupt multiple cultural and ceremonial activities, compounding mental, cultural, and physical well-being issues for Tribes.^265,352,363 Impacts to these cultural resources and sites disrupt intergenerational teachings, an important component of Indigenous health and a method to address intergenerational trauma (KM 27.6).³⁶⁴

Climate Action Can Benefit Human Health and Address Inequities

Historically, the intersection of climate change and health has been unclear, leading to insufficient capacity and resources for health agencies to properly respond and prioritize climate change actions.³⁶⁵ However, because of the health consequences of recent extreme events, public health responses to climate change have become an essential part of climate adaptation, and health resilience frameworks, such as the CDC’s Building Resilience Against Climate Effects (BRACE) or Oregon’s Climate Equity Blueprint, are becoming more common.³⁶⁶ Many strategies—such as setting universal climate and health goals and providing adequate resources to communities and populations to reach these goals—offer promise for avoiding negative public health outcomes due to climate change and can advance regional resilience (KM 27.1).³⁶⁷ For example, investments to increase electric vehicle adoption and active transportation (e.g., walking, biking) are expected to lead to greenhouse gas emissions reductions, improvements in air quality, and reductions in fatal traffic accidents.³⁶⁸ Investments in cooling options—such as shade coverage from trees, cross-ventilation in apartment units, and air-conditioning capacity—can support communities, particularly formerly redlined communities, in adapting to extreme heat events (KM 27.1).³⁶⁹

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The heritage of the Northwest is intertwined with the diversity of landscapes, economies, and quality of life (Figure 27.10). Climate change affects all these core characteristics of the Northwest, with impacts on the quality of life and sense of place—the attachment or relationship that people feel to their locations and environment—for all communities and the ability to share the familiar parts of where one lives with others and across generations.³⁷⁰ While there are differences among cultures’ relationships, there are deep commonalities. Supporting the continued emotional and cultural well-being of residents across the region will require a mutual appreciation from multiple perspectives across diverse communities.

Sense of Stability and Security

Climate change can negatively affect peoples’ sense of security and stability due to disruptions to supply chains and food systems, which underpin economies and communities (KM 18.2; Focus on Risks to Supply Chains).^371,372 For example, a forest products industry requires regular inputs of timber and cannot thrive on supplies that increasingly come in pulses or waves due to drought, wildfires, and insect infestations.³⁷³ Climate change impacts to natural resource economies will affect residents’ financial security and livelihoods (KM 27.3) and will have cascading impacts across regional to international economic systems (KM 19.2).

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The heritage of the Northwest is intertwined with the diversity of landscapes, economies, and quality of life.

Figure 27.10. These photos illustrate different heritages, cultural traditions, and amenities at risk from climate change. (top left) Coastal change is threatening beaches and shellfish habitat for the Swinomish Tribe, threatening cultural activities like the Swinomish Clam Bake. (top right) Fire retardant drops protect vulnerable homes in the wildland–urban interface. (center left) Culturally important foods, such as camas, will be affected by climate change. (center right) Climate change is affecting salmon, potentially affecting the ability of some Tribes to roast and smoke salmon. (bottom left) Wildfire smoke days are increasing, affecting school recreation opportunities. (bottom right) Warmer winters, such as the winter of 2015, will lead to less winter snow, affecting ski resorts such as Mount Baker Ski Resort, Washington, which had no snow on February 15, 2015, during the height of ski season. Photo credits: (top left) ©Richard A. Walker; (top right) National Interagency Fire Center; (center left and bottom left) ©Charles Luce; (center right) ©Samantha Chisholm Hatfield; (bottom right) ©Duncan Howat.

Many in the Northwest have moved from city centers to an expanding wildland–urban interface (WUI) (Figure 27.11),^102,103,104 increasing community exposure to wildfires and floods.³⁷⁴ Homes dependent on shallow wells are at risk from more frequent and intense drought conditions (KM 27.4).³⁷⁵ Increases in the frequency of algal blooms or outbreaks of forest diseases and pests reduce the value of homes with water frontage or surrounded by forest (KM 19.3).^376,377,378 The decline of home values, aggregated across communities, can lead to local economic and community instability by reducing the desire or ability to rebuild after fires and floods.^379,380 Although insured households may be able to rebuild, climate risks can increase insurance costs and decrease insurance availability, affecting which residents and businesses thrive in the future.³⁸¹

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The growth of homes in the wildland–urban interface puts an increasing number of people at risk of wildfire and flooding.

Figure 27.11. The maps show growth in the wildland–urban interface (WUI; dark purple) areas, which are associated with increased wildfire and flooding risks, between 1990 and 2020 near Bend, Oregon (a); Spokane, Washington (b); and Boise, Idaho (c). Bend and Spokane have experienced fast rates of development and population growth that have led to new areas being developed as WUI. Figure credit: USDA Forest Service, NOAA NCEI, and CISESS NC.

Environmental Amenities and Sense of Place

Northwest residents value the region for its environmental amenities like good air and water quality and proximity to recreational opportunities.^263,382 Climate change has already started and will continue to disrupt many kinds of outdoor recreational activities.^79,383 Multiple recreational seasons have simultaneously shortened and shifted. Skiing and snowmobiling seasons have started later and become shorter over much of the region, especially in the Cascades,^13,384 affecting winter recreation businesses (KM 27.3). Loss of spring snowmelt will shift opportunities for rafting, kayaking, and canoeing into rainy winter months, when rapidly fluctuating flow conditions are less safe. Water-based recreation demand is expected to increase in spring and summer months; however, reduced water quality and harmful algal blooms are expected to restrict these recreation opportunities.⁷⁹

Many previously forested trails and camping areas have already lost forest cover due to wildfires and drought.³⁸⁵ As the frequency of disturbances increases, so will the number of dead and downed trees,³⁸⁶ closing roads, trails, and campgrounds and potentially causing injuries or death for recreationists.³⁸⁷ Greater flooding risk in winter months will pose risks to recreational facilities and users.³⁸⁸ More frequent smoke and extreme heat events will increase risks to outdoor summer recreationists, especially for high-exertion activities.³⁸⁹ State health agencies, such as the Idaho Department of Health and Welfare, have developed recreation guidelines for K–12 and adult fitness activities and sports in response to increasing wildfire smoke days and decreased air quality.³⁹⁰

Climate change will also affect recreational and subsistence hunting, gathering, and fishing activities. Although some game species may benefit from increased shrub cover and reduced winter mortality, increasing populations can lead to other challenges, affecting managed resources and increasing pathogen spread.^391,392 Algal blooms and increased toxin levels will lead to shellfish harvest closures, sometimes lasting entire seasons. While these impacts will affect recreational hunters and fishers, impacts will be greater for households and communities that are nutritionally dependent on these resources, such as Tribal communities and households reliant on subsistence diets.³⁹³

Amenity migration, or movement of people to areas with higher environmental quality or increased access to amenities, will be affected by climate change in various ways.^394,395 For example, people moving to the WUI to be closer to environmental amenities will experience increased risks of wildfires and, in some cases, landslides (Figure 27.11). Additionally, there are compounding challenges for communities that are receiving an influx of amenity migrants, especially rural and low-income communities where established residents provide the labor force but may become priced out by increasing costs of housing and other necessities.^396,397 Interacting stresses between socioeconomic and development impacts associated with migration and climate change will affect communities in high-amenity areas in the Northwest, such as ski communities in the Cascade Range or island communities in the San Juan Islands.³⁹⁸

Tribal Cultures and Connection to the Land

Climate change has affected Tribal harvesting, hunting, and ceremonial practices.³⁹⁹ Climate change will impact Pacific salmon (KM 27.2) and other cultural resources such as Pacific lamprey, deer, elk, bear, berries, eel, flounder, sturgeon, shellfish, and seaweeds.⁴⁰⁰ Plant die-offs and range shifts can disrupt and impede Tribal access to traditional foods, thereby affecting Tribes’ and Indigenous Peoples’ sense of place and connections (KM 27.5).³⁶³ Extreme weather events and extreme heat and cold can prevent Tribal members, especially elders, from participating in Tribal ceremonies. Access to ceremonial sites can also be disrupted or damaged by flooding, landslides, and wildfires, exacerbating degradation associated with other land-use decisions (KM 27.1).

Indigenous Knowledges can be utilized to increase resilience to climate change for Tribes.²⁵¹ Tribal landscape management is one method for maintaining connections to landscapes and preserving ceremonial sites, medicinal plants, and gravesite locations for future generations.^401,402,403 However, federal, state, and local jurisdictions have prevented some Tribes from utilizing Indigenous management techniques such as prescribed burning, which can remove underbrush to reduce fire risk and establish wildlife corridors (KM 27.2), thereby limiting Tribes’ ability to exercise their sovereignty and to maintain a sense of place for future generations.^{404,405,406,407,408} Western adaptation options of replacement, fortification, or relocation (KM 27.4) may not be possible or appropriate, as some sites (e.g., gravesites and ceremonial sites) do not have one-to-one exchange equivalents. Despite these limitations, federal–Tribal partnerships can increase landscape resilience to future climate change risks.^409,410

Maintaining a Sense of Place and Heritage for the Northwest

Climate change poses an existential threat to the ability of Northwest communities to maintain their sense of place and heritage for future generations. Many cultures rely on nature-based experiences to transfer knowledge and form cultural identity. For example, the Swinomish Tribe holds cultural clam bakes, where community elders transfer Traditional Knowledges about the natural world that are vital to maintain their cultural well-being and heritage.³⁹⁹ However, recent shoreline changes and projected beach loss threaten access to these culturally important shellfish harvest areas, reducing opportunities to hold cultural clam bakes.⁴¹¹

Communities across the Northwest pride themselves on their environmental values and actions, such as promoting conservation or voluntarily employing sustainable practices. Leveraging these community values can lead to innovative climate adaptation and mitigation policies at the local level,^412,413 furthering regional climate mitigation and adaptation goals (KM 27.4) to ensure that the heritage and the communities of the Northwest persist for future generations.

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