Linkage Between Observed Climate and Regional Risks

The Northwest provides for a diverse natural resource economy, from coastal fisheries, to Douglas fir plantations, to vineyards, to semiarid rangelands, to dryland and irrigated farms. The region is the Nation’s top producer of 28 agricultural products, one of the leading national producers of timber products, and is widely recognized for salmon and shellfish fisheries. The agriculture, forestry, and fisheries sectors accounted for over 700,000 jobs and more than $139 billion in sales in 2015 (in 2015 dollars; Figure 24.3).¹⁷

The outdoor recreation sector is another important contributor to local economies in the Northwest. The Outdoor Industry Association (2017)¹⁸ estimates that the region’s outdoor recreation economy generates $51 billion (based on 2017 data, dollar year not reported) in consumer spending each year and provides around 451,000 jobs. These economic benefits are particularly important in rural and tribal communities whose income base is largely dependent on natural resource economies and supporting industries (Ch. 10: Ag & Rural, KM 4; Ch. 15: Tribes). Outdoor activities, including skiing, boating, rafting, hunting, fishing, hiking, and backpacking, are impacted by climate variability, whether through less summer water, warmer streams, less snowfall, or loss of forests. Comparing high-snowfall to low-snowfall years in the Northwest between 1999 and 2009, each low-snowfall year resulted in more than 2,100 fewer employees and a $173 million reduction in ski resort revenues ($189 million in 2015 dollars) compared to the high-snowfall years.¹⁹ Impacts on the skiing industry were especially prominent during the warm 2015 winter, when snowpack was at record lows (see Box 24.7).

Both the natural resource commodity sector and the outdoor recreation industry are sensitive to short- and long-term climate variability. The record-setting 2015 drought and above-average temperatures were a challenge for agriculture. The reduced availability of water for irrigation coupled with heat stress impacted production and livestock health (see Box 24.7) (see also Ch. 10: Ag & Rural, KM 2 and 3; Ch. 3: Water, KM 3). In Northwest forests, tree mortality driven by wildfires, insects, and disease have been more prevalent over the last two decades due to drought conditions and increased temperatures (e.g., Hicke et al. 2013¹³), and timber managers are adjusting to increased risk of loss by shortening rotation rates, reducing investment in some areas, and changing planted species.^20,21

Commercial fisheries are also sensitive to climate variability. River temperatures increase during warm and dry years, resulting in fish kills of migrating and spawning salmon; these fish kills have consequences several years in the future.^22,23,24 In 2015, July water temperatures in the lower Columbia River and its tributaries were higher than in any other year on record, leading to a high rate of mortality for endangered sockeye and threatened Chinook.^25,26 The record temperatures in 2015 were part of a long-term trend of declining low flows²⁷ and warming streams.^28,29 Increasing ocean temperatures and acidity also impact fish survival, species abundance, and predator–prey distribution and timing.³⁰ In 2015, the increased ocean temperatures were part of an ocean heat wave coined “the Blob,” which fueled a coast-wide harmful algal bloom that affected commercial, recreation, and tribal subsistence fisheries (see Box 24.7) (see also Ch. 9: Oceans).¹⁰

Future Climate Change Relevant to Regional Risks

Shifts in timing of water supply, such as earlier snowmelt and declining summer flows, can adversely impact irrigated crop productivity, particularly where access to reservoir water storage and/or groundwater is limited (Ch. 10 Ag & Rural, KM 2).³¹ Planning studies for Northwest reservoirs suggest a significant increased need for reservoir storage to meet future summer irrigation demands under climate change scenarios.^32,33 Irrigation demands among farmers in the Columbia River Basin are projected to increase 5% in response to climate change by the 2030s; however, actual water demands will vary depending on adaptive management decisions and crop requirements.³⁴ For dryland wheat production, shifting planting dates and rising temperatures coupled with increased atmospheric carbon dioxide (CO₂) and associated increases in plant water use efficiency are projected to lead to improved wheat yields under both lower and higher scenarios (RCP4.5 and RCP8.5) through the end of the century.^35,36

Specialty crops, including apples and other tree fruits, are already experiencing changes. Higher spring temperatures have led to earlier flowering, which can lead to a mismatch with the availability of pollinators required for fruit setting (the process of flowers becoming fruit)³⁷ and can affect fruit quality as well as yield. Additionally, summer heat stress can lead to sunburn scald on apples and softer berry crops that can be damaged in transport and harvest,³⁷ which can decrease fruit quality and the farmers’ selling price. Heat stress can also decrease livestock health and increase parasite abundance.³⁸ Projected warmer and drier summer seasons will likely reduce forage quality and quantity,³⁹ with varied impacts across forage and rangeland types.⁴⁰ Impacts to the quality and quantity of forage will also likely impact farmers’ economic viability as they may need to buy additional feed or wait longer for their livestock to put on weight, which affects the total price they receive per animal.

Forests in the interior Northwest are changing rapidly because of increasing wildfire⁸ and insect and disease damage,^41,42 attributed largely to a changing climate (Ch. 5: Land Changes).⁴³ These changes are expected to increase as temperatures increase⁴⁴ and as summer droughts deepen.⁴⁵ For forests that grow in areas with snowpack, the declining snowpack is projected to worsen summer drought conditions, increasing vulnerability to drought caused by year-to-year precipitation variability.⁴⁶ Some forests in the region will increase in potential productivity (growth without consideration of increased disturbance) due to a combination of increased CO₂ and a longer growing season length, while others will decrease due to reduced availability of summer moisture (Ch. 6: Forests).⁴⁷ Timber supplies from the drier eastern Northwest forests are the most affected by climate-related disturbances,⁴⁸ resulting in intermittent and unpredictable timber supplies and depressed timber prices⁴⁹ in an already difficult global market. This could affect mill investments and the long-term viability of forestry as an economic activity, particularly in the more remote areas of the region where transportation costs to mills are high.

The negative impacts on Northwest fisheries associated with ocean warming, acidification, and harmful algal blooms are expected to increase (Ch. 9: Oceans).⁵⁰ This could lead to extensive fisheries closures across all of the region’s coastal fisheries, with severe economic and cultural effects on commercial and subsistence shellfish industries. The warming ocean is projected to result in range shifts, with some Northwest species shifting as far north as the Bering Sea.⁵¹ However, these range shifts may also open up new fishing opportunities in the Northwest,^51,52 depending on interstate and international coordination between management agencies. As the marine ecosystems respond to climate change, there will likely be consequences to existing place-based fisheries resources, as well as potential benefits and new resources. How the shifting resources will be managed and how existing fishing rights and allocations will change over time is currently not known (Ch. 9: Oceans, KM 2).

Projections for increased stream temperature indicate a 22% reduction in salmon habitat in Washington by late century under a high emissions future (the A1F1 scenario).⁵³ This habitat loss corresponds to more than $3 billion in economic losses due to reductions in salmon populations and decreases in cold-water angling opportunities ($3.3 billion in 2015 dollars, discounting method not specified).⁵³ Freshwater trout are sensitive to habitat connectivity and wildfire, so land management practices will affect how trout respond to climate change.⁵⁴ Overall, commercial fishing performance and abundance are expected to decline as the climate changes.^50,55,56,57

Decreases in low- and mid-elevation snowpack and accompanying decreases in summer streamflow are projected to impact snow- and water-based recreation, such as downhill and cross-country skiing, snowmobiling, boating, rafting, and fishing. Climate change could decrease snow-based recreation revenue by more than 70% annually in the Northwest under a higher scenario (RCP8.5).⁵⁸ Impacts to snowpack and, consequently, winter recreation will likely occur later in the colder, higher-elevation mountains in southern Idaho.⁵⁹

Challenges, Opportunities, and Success Stories for Reducing Risk

Climate change will likely have both positive and negative effects on the natural resource sector; however, cost-effective adaptation approaches that build agro-ecosystem resilience are likely needed to maintain agricultural livelihoods (see Box 24.1). A shift in plant hardiness zones, or the ability of a given plant to thrive in a specific location, is expected, changing the suitability of growing certain crops in specific locations;^60,61 such shifts may change land uses entirely (Ch. 5: Land Changes, KM 2). For example, Northwest wine producers may see the potential for growing higher-quality and higher-value wine grape varietals,⁶² but changing hydrologic regimes are projected to limit available water supplies for irrigation, requiring water storage or alternative water sources to maintain productivity. Over the longer term, changes to average growing season temperatures and the number of severe hot days are projected to reduce premium wine grape production in the Northwest, potentially shifting prime growing areas further north.⁶³ To take advantage of shifting opportunities, farmers would need to consider costly changes and investments in new farming practices and territories in advance of projected climate change.^37,64

Livestock producers in the Northwest have an advantage over those in other U.S. regions where climate change impacts are likely to be more severe (Ch. 10: Ag & Rural, KM 3).⁶⁵ However, livestock production costs are still likely to increase in the Northwest due to supplemental feeding and watering requirements and the need for reducing livestock numbers in response to warmer and drier summers.⁴⁰

The prevalence of wildfires, insect infestations, disease epidemics, and drought-induced dieback of Northwest forests have heightened forestry managers’ awareness of potential climate change impacts. Over the long term, these sustained impacts are projected to fundamentally alter forest composition and land cover (Ch. 6: Forests, KM 1; Ch. 5: Land Changes). Forest management adaptation strategies are being developed,^21,66 including strategies that address drought-related risks, improve the reliability of forest transportation infrastructure, and protect forest-related ecosystem services (Ch. 6: Forests, KM 3).⁶⁷ Vulnerability assessments and adaptation plans have been completed, or are in progress, for almost every National Forest and Park in the region.⁶⁸

Marine and ocean environments of the Northwest are projected to continue to change gradually in response to climate change, but the full extent of the potential effects on fisheries is not well understood.⁶⁹ In the near term, the fisheries industry can use existing strategies that work within the limits of the natural environment to maintain species abundance, avoid extinction, or increase harvests, such as limited fishing seasons, developing quota systems, and expanding aquaculture (Ch. 9: Oceans, KM 2). In the longer term, particularly as large-scale range shifts occur, species-dependent management changes and alternative management systems are likely to be needed to maintain fisheries and open up new fisheries opportunities.⁷⁰

Despite the many strategies for reducing risks, adaptive capacity is not uniform across the natural resource sector. Given the heterogeneity across climatic and natural resource industries in the region, it is not likely that productivity gains and losses will be felt equally across the broad diversity in the region.^71,72

Emerging Issues

Climate stressors such as increased temperatures, CO₂ fertilization, and precipitation changes are projected to impact pest, disease, and weed pressures (Ch. 10: Ag & Rural).^77,78 Improved modeling of climate stressors on yields and crop quality will likely enhance the understanding of climate change effects and inform adaptation options³⁶ and assist in addressing farmers’ concerns about future pest and pathogen impacts in the region.^79,80 Water shortfalls are also likely to continue during drought periods despite adaptation efforts focused on water efficiency and reducing water usage (Ch. 3: Water, KM 1). Western water law assigns a priority date to each right based on seniority, so junior (or more recent) water rights are more likely to be adversely affected under shortage conditions than those with senior water rights. More studies would enhance the understanding of which watersheds are at the greatest risk and what, if any, changes could address water limitations in the future. The development of more robust water markets may facilitate adaptation to climate change in the arid and semiarid Pacific Northwest; however, considerable institutional barriers currently prevent their full implementation.⁸¹

Although much is being researched with respect to the effects of climate change on forests and associated ecosystem services, far less has been explored with respect to timber markets. Even then, most of the focus has been on changes in forest productivity overall (e.g., Latta et al. 2010⁴⁷) and less on the consequences of disturbance. Research is absent on the effects of potential increases in supply volatility and the consequences for investment and ultimately on harvest and milling jobs.

Ocean acidification poses a direct threat to shellfish and other calcifying species that are at the base of the food web (Ch. 9: Oceans, KM 1). The prominence of the impact on shellfish farms in the Northwest led to the installation of an ocean monitoring system to track ocean acidity. Although calcium carbonate can be used to increase seawater pH in a hatchery setting,⁸² the same approach cannot be used in the open ocean to prevent shell dissolution.⁸³ The broader food web consequences of decline in calcifying species is an area of active research (Ch. 9: Oceans).

There is a great deal of uncertainty regarding impacts on the economic viability of primarily rural, natural-resource-based economies in the region, particularly the degree to which individual sectors are integrated into global commodity markets, which are likely to vary immensely and be difficult to predict (Ch. 10: Ag & Rural; Ch. 16: International, KM 4).⁵⁰

Linkage Between Observed Climate and Regional Risks

The intangible values and aspects of the Northwest’s natural environment that support a high quality of life for its residents—wildlife, habitat, and outdoor recreation—are at risk in a changing climate. Tribes and Indigenous communities that rely heavily on the natural environment for their culture and heritage are also at risk.

The Northwest’s native wildlife is impacted by climate variability and change directly through temperature shifts, water availability, and extreme events, and indirectly through loss or fragmentation of habitat.⁸⁴ Changes in climate can alter the balance among competing species or predator–prey relationships (e.g., Wenger et al. 2011⁵²). Three wildlife categories are of principal concern: already sensitive or endangered species, snow-dependent species, and game species. While the first two groups of animals are generally negatively impacted by changes in climate, some game species, such as deer and elk, may thrive. Game species are of concern not because of their sensitivity to changes in climate and habitat but because of their notable value for recreational hunting and as key cultural resources for tribes. Climate change is also projected to impact First Foods, or foods that tribes have historically cultivated for subsistence, economic, and ceremonial purposes. First Foods vary among tribes but often include berries, roots, water, fish, and local wildlife.^85,86 Additionally, nearly half of all adults in the region participated in wildlife-related recreation in 2010.⁸⁷ As temperatures increase, the demand for warm-weather outdoor and water-based recreation increases, and visitation rates at local, state, and national parks increase.^88,89,90 However, boating and other water-based recreation opportunities are likely to decline in the future when summer streamflows and reservoir levels are low. Additionally, popular winter sports and snow-based recreational activities, such as downhill skiing, cross-country skiing, and snowmobiling, have been dramatically impacted by reduced snowfall (see Box 24.7). In low-snowfall years, Washington and Oregon show the highest percentage drop of skier visits, meaning that residents and visitors are losing desirable skiing opportunities.⁹¹

Future Climate Change Relevant to Regional Risks

Wildlife responses to a changing climate are varied and complex (Ch. 7: Ecosystems). Some species, such as cavity nesting birds, will very likely benefit from greater disturbance.^92,93 Others, particularly snow-dependent species, will likely be unable to persist under climate change.⁹⁴

Game species are expected to have diverse responses to climate change. Longer dry seasons and more pronounced droughts are projected to reduce wetland habitat extent and duration, causing changes in waterfowl movement. Increased fire disturbance, on the other hand, will likely increase shrub cover, a preferred food for deer and elk;⁹⁵ reduced winter snowpack may increase food availability in winter; and warmer temperatures reduce winter stress, all of which would support higher deer and elk populations. The primary climate-related impact on game species will likely come from increases in disease and disease-carrying insects and pests.⁹⁶

Temperature-sensitive bull trout, salmon, and other water-dependent species, such as amphibians, are most vulnerable to increased habitat fragmentation.^97,98,99 Increased frequency of extreme events such as flooding, debris flows, and landslides are projected to alter habitats and likely cause local extinctions of aquatic species.

Increased winter streamflow and decreased summer flow are projected to threaten salmon spawning,¹⁰⁰ compromising salmon hatchery and reintroduction efforts.¹⁰¹ Projected increases in winter storm intensity will likely lead to higher river flows and increased sediment loading that can bury salmon eggs and reduce salmon survival.¹⁰¹ Rising stream temperatures, ocean acidification, and loss of nearshore and estuarine habitat also increase salmon mortality across all phases of the salmon life cycle.¹⁰²

Shellfish beds are threatened by sea level rise, storm surge, and ocean acidification.^85,103 Species moving out of traditional hunting, gathering, and fishing areas are projected to impact resource access for many tribes.^101,104 Increasing wildfire frequency and intensity are changing foraging patterns for elk and deer, and increased prevalence of invasive species and disease will likely diminish both wildlife and foraging for traditional plants, berries, roots, and seeds.¹⁰⁵

In winter, continued decreases in lower-elevation snowpack are projected to impact snow-based recreation.¹⁹ Less snowpack and earlier melting of snowpack will likely result in decreased water availability, reducing the quality, quantity, and availability of water-based recreational opportunities, such as boating, rafting, and fishing.¹⁸

Increased wildfire occurrence is projected to degrade air quality and reduce the opportunity for and enjoyment of all outdoor recreation activities, such as camping, biking, hiking, youth sports, and hunting. Degraded air quality also directly impacts human health and quality of life (see Key Message 4).

Recreational ocean fishing opportunities are expected to decline under future climate change scenarios,^55,56,57 and it is likely that fishery ranges will change.⁵¹ Recreational razor clamming on the coast is also expected to decline due to cumulative effects of ocean acidification, harmful algal blooms, higher temperatures, and habitat degradation (see Figure 24.7 and Key Message 1).

Challenges, Opportunities, and Success Stories for Reducing Risk

Historical and projected changes in amenities affecting the quality of life in the Northwest, such as wildlife, recreation opportunities, and edible plants, form a key challenge for managers of these resources. Informed management, however, can reduce the consequences to those who enjoy and value these resources. Sensitive and endangered plant and animal species currently require special management considerations due to historical habitat changes and past species declines. Management of these species can substantially constrain land and water management options, and the protection of these species will likely become more difficult as suitable habitat is lost.

Game species are already managed. Further management of waterfowl habitat is projected to be important to maintain past hunting levels. If deer and elk populations increase, the pressures they place on plant ecosystems (including riparian systems) may benefit from management beyond traditional harvest levels.

The cultural practice of harvesting and consuming First Foods is integral to tribes and Indigenous health (Ch. 15: Tribes).¹⁰⁶ Many tribes, such as the Confederated Tribes of the Umatilla Indian Reservation are using climate change vulnerability assessments and climate change adaptation plans to alter how First Foods are managed.¹⁰⁷ Tribes can exercise their sovereign rights to manage their resources in a self-determined and culturally appropriate manner, thereby increasing each tribe’s adaptive capacity to respond to climate change impacts on tribal lands, foods, health, and cultures (see Box 24.2).^85,108,109 Tribes can also increase their adaptive capacity through regional networks, such as the Columbia River Inter-Tribal Fish Commission, that support tribal and Indigenous planning and management (see Key Message 5).

As fisheries become stressed due to climate change, additional management strategies are likely to be needed to maintain fish populations. Strategies that focus on habitat quality and quantity are likely to be the most successful.¹¹⁰

Emerging Issues

Some of the species likely to be affected by climate change are already imperiled by population declines, extirpations, or even extinction as a result of historical changes in habitat and other factors. Climate change adds urgency to addressing existing and emergent challenges. Research is already active in identifying resilient habitats (e.g., Morelli et al. 2016, Luce et al. 2014, Isaak et al. 2016^114,115,116) and the means for maintaining and improving habitat resilience in the face of increasing climate and disturbance pressure.¹¹⁷ Habitat modeling that includes projections of natural resource shifts, fragmentation, and identification of new wildlife corridors are projected to be beneficial in supporting land and water management decisions that benefit people, recreation, and the Northwest’s varied wildlife.

An institutional network of land, wildlife, and fishery management agencies, tribes, and non-governmental conservation organizations has already successfully reversed negative trends in many fish and wildlife populations caused by other human activities.¹¹⁸ These same groups are exploring methods to improve fish and wildlife resilience in a changing climate. Many habitat improvement activities, a cornerstone of conservation biology, also provide flood mitigation, climate mitigation, adaptation, and ecosystem service co-benefits (Ch. 6: Forests).^119,120 Despite proactive management and adaptation, it is likely that species not currently listed as endangered could become endangered over the next century, and eventual extinctions are likely, yet challenging to predict.¹²¹

First Foods are an important aspect of tribal and Indigenous health and well-being,¹²² and they can be used as indicators in tribal health assessments and climate adaptation plans.^112,123 The loss or decline of First Foods is projected to have cascading physical and mental health impacts for tribes and Indigenous peoples (see Key Message 5) (see also Ch. 15: Tribes, KM 2).^124,125 However, more research to refine these indicators would better support decision-making (see Box 24.2).^123,126

Social indicators link a decline in quality of life in the Northwest to loss of recreational opportunities due to climate change impacts,¹²⁷ but the causal links are not well understood. Additionally, future human migration and population increases may alter the relationship and nature of recreation in the Northwest.¹²⁸ As the population increases, the demand for snow-based recreation is likely to also increase. However, it is not clear how the limited availability of snow-based recreation (for example, a shorter ski season) in the Northwest over the long term can influence interest in snow sports in contrast to alternatives.

Linkage Between Observed Climate and Regional Risks

Infrastructure plays a critical role in keeping the Northwest’s economy running smoothly. Roads, highways, railways, and ports facilitate the movement of people and goods within the region and support valuable import and export markets. Powerlines and substations maintain the reliable supply of electricity to homes, businesses, schools, and hospitals. Dams and reservoirs manage streamflow to minimize flood risks, generate electricity, and provide water supply for irrigation and human consumption. Groundwater wells act as an important water source for agriculture and drinking supplies across much of the region. Levees and seawalls prevent damage to homes and property along rivers and the coast. Culverts manage water flows to protect roadways from flooding and assist with fish passage, including for migrating salmon. Storm water and wastewater systems help minimize flooding, especially in urban areas, and are critical for maintaining water quality. However, most infrastructure is designed for a historical climate, and damage and disruptions caused by extreme events demonstrate existing infrastructure vulnerabilities that are likely to increase in a changing climate (Ch. 3: Water, KM 2; Ch. 4: Energy, KM 1; Ch. 11: Urban, KM 2; Ch. 12: Transportation, KM 1; Ch. 28: Adaptation, KM 2).

Services provided by infrastructure can be disrupted during extreme weather and climate events, illustrating the sensitivity of these systems to climate variability and change (see Box 24.3). During the 2015–2016 extreme El Niño winter, wave energy along the West Coast was about 50% above normal.¹⁶ Several major storms hit northwestern Oregon, bringing record-breaking rainfall, high winds, and high tides. Tillamook County in Oregon experienced a state of emergency that included major highway and road closures due to flooding, failed culverts, landslides, and sinkholes. Disruptions in transportation networks affected access to food, healthcare, and social services (see Key Message 2) (see also Ch. 12: Transportation, KM 2).¹³⁰ The event highlighted the need to maintain detour routes that were valuable in reaching communities that could become isolated. Wave and storm surge energy along the Pacific Northwest coast is expected to increase with climate change.¹³¹ Continuing efforts to build resilience within the health and transportation sectors in response to flooding hazards will likely help the county weather future storms.¹³⁰

Heavy rainfall can lead to slope instabilities and landslides, which can close roadways and railways. Along the Amtrak Cascades Corridor, more than 900 coastal bluff landslides have blocked the tracks and shut down rail service since 1914, with over 240 disruptions occurring between 2009 and 2013.¹³² Each landslide results in a minimum 48-hour moratorium on commuter rail service. The Washington State Department of Transportation is implementing a Landslide Mitigation Action Plan to proactively address the climatic and other factors contributing to landslide-based rail closures.¹³²

Landslides during winter storms have also closed major Interstates, such as the December 2015 closure of eastbound Interstate 90 near Snoqualmie Pass and the February 2017 closure of westbound Interstate 90 near Issaquah.

Wildfires can result in road and railway closures, reduced water quality in reservoirs, and impacts on the energy sector. The Goodell wildfire in August 2015 forced Seattle City Light to de-energize transmission lines around its Skagit River Hydroelectric Project for several days.¹³³ The combined impact of damages and lost power production totaled nearly $3 million (in 2015 dollars).¹³⁴ The Eagle Creek fire along the Washington–Oregon border in 2017 led to the closure of Interstate Highway 84 and an adjacent railway, likely increasing shipping costs and creating negative economic impacts on tourism and regional small businesses.¹³⁵

Drought conditions also present challenges for infrastructure, especially water supplies. In Washington, the Department of Ecology allocated almost $7 million in drought relief funds in 2015 (in 2015 dollars). Relief grants were used to provide backup or emergency water supplies for irrigation or human consumption where wells were failing or pumping capacity was inadequate.¹³⁶ These small and typically rural systems are relatively more vulnerable to drought impacts when compared to larger urban systems (Ch. 10: Ag & Rural, KM 4).

Future Climate Change Relevant to Regional Risks

Climate change is expected to increase the frequency and/or intensity of many extreme events that affect infrastructure in the Northwest. Available vulnerability assessments for infrastructure show the prominent role that future extremes play. Since much of the existing infrastructure was designed and is managed for an unchanging climate, changes in the frequency and intensity of flooding, drought, wildfire, and heat waves affect the reliability of water, transportation, and energy services.

Hydrologic change will likely be an important driver of future climate stress on infrastructure. As higher temperatures increase the proportion of cold season precipitation falling as rain rather than snow, higher streamflow is projected to occur in many basins, raising flood risks.^{137,138,139,140} An increased risk of landslides is also expected, as more mixed rain and melting snow events occur in low- to mid-elevation mountains.¹⁴¹ Increases in the amount of precipitation falling in heavy rainfall events (including atmospheric rivers)¹⁴² are anticipated to magnify these risks. Along the coast, sea level rise is projected to increase flood risks in low-lying areas and will likely magnify the potential for coastal erosion (Ch. 5: Land Changes) and infrastructure damage during extreme events with high storm surge and wave hazards. By the end of the century, the upper sea level rise projection of 4.3 feet¹⁴³ would impact significant infrastructure investments throughout the Northwest, particularly in the low-lying urban areas of the Puget Sound and Portland (Ch. 8: Coastal).

Spring and summer streamflows are anticipated to decline in basins that have historically relied on snowmelt, and low flow periods are projected to be more prolonged and more severe. If observed declines in higher elevation precipitation continue,¹⁴⁴ this would exacerbate low streamflow conditions,²⁷ resulting in decreased water supply and reservoir storage. Climate change can affect water quality as well (Ch. 3: Water, KM 1). Higher air temperatures, lower streamflow, and decreases in rainfall are expected to raise summer stream temperatures, making it more difficult to meet water quality standards. In coastal areas, sea level rise will likely lead to saltwater intrusion into groundwater supplies.

Challenges, Opportunities, and Success Stories for Reducing Risk

Anticipated future impacts on infrastructure create opportunities for addressing existing environmental and social goals. For example, actions by the city of Boise, Idaho, to improve water quality are likely to minimize some of the impacts associated with a warmer climate. In Boise, a phosphorous removal facility reduces the amount of phosphorous entering rivers, thereby reducing the need for water treatment facility upgrades¹⁴⁵ and perhaps also preventing downstream algal blooms, which are anticipated to become more common in a warmer climate.

The Northwest has several examples of successful cross-sector collaboration between resource managers and scientists to plan and prepare for climate impacts across multiple sectors (Ch. 17: Complex Systems, KM 3). In Portland and Multnomah County, Oregon, the 2030 Climate Change Preparation Strategy and 2050 Climate Action Plan have incorporated strategies across multiple sectors including water systems, natural and built infrastructure, and human health, with specific social equity considerations woven throughout.^146,147 For many socially vulnerable populations, limited access to transportation, businesses, and other community resources can inhibit their ability to cope with climate impacts. Addressing these disparities can have the added benefit of bolstering resilience (see Key Message 5). Building and strengthening partnerships across sectors will continue to be important in addressing these complex challenges.

Infrastructure managers in larger urban areas like Seattle and Portland have invested in building climate resilience for their systems (e.g., Vogel et al. 2015, Mauger et al. 2015^139,148) (see also Ch. 11: Urban, KM 4), often partnering with researchers to develop tailored climate risk information and adaptation strategies. However, in many parts of the Northwest, especially areas outside urban centers, the lack of redundancy within infrastructure systems will likely be an important factor in limiting adaptive capacity (Ch. 12: Transportation, KM 2; Ch. 10: Ag & Rural, KM 4). Understanding the risks associated with these systems remains a challenge, as impacts could emerge directly from climate events or from the interaction of non-climate and climate stressors (such as equipment failure making a water system more susceptible to subsequent drought). For example, in the Washington Department of Transportation’s vulnerability assessment, lifeline roadways that serve as the only means to access communities often emerged as highly vulnerable.¹⁴⁹ Disruptions to these roadways could cut off communities, preventing supplies or first responders from arriving. The lack of redundancy in transportation networks has also been noted for several of the region’s National Parks, contributing to their vulnerability.¹⁴¹ In a similar vein, the Washington Department of Health is examining aspects of groundwater systems that contribute to climate vulnerability. They have found that many groundwater systems are single source and lack any back-up supplies (see Figure 24.12). If supplies are disrupted, either by climate or non-climate stressors, surrounding communities may be forced to transport water to their area or relocate to a place with a more reliable supply (Ch. 3: Water, KM 2).

An additional challenge in addressing future impacts to infrastructure is cost. Projects for replacing, retrofitting, or improving dams, reservoirs, pipelines, culverts, roadways, electrical transmission and distribution systems, and shoreline protection can have costs in the billions (e.g., Wilhere et al. 2017¹⁵⁰).

Managing water in the face of a changing climate also presents an opportunity for transboundary collaboration and coordination. For the Columbia River, projections of future streamflow have been generated for use by U.S. federal agencies, in partnership with Canadian agencies.¹⁵¹ The information about future hydrology can support infrastructure decisions about water supply management, flood risk management, and hydropower production (Ch. 3: Water, KM 3; Ch. 16: International, KM 4).

Emerging Issues

Infrastructure managers are beginning to consolidate planning for the combined risks of sea level rise, flooding, and seismic hazards, as well as tsunami risks that can also arise from a major earthquake event. Going forward, it could be useful to identify strategies that enhance community resilience and emergency response capacity to many types of hazards and potential disruptions.

Infrastructure management is traditionally oriented to protecting assets and services in place. The use of “green” or hybrid “green and gray” infrastructure (e.g., Kittitas County Flood Control Zone District 2015, City of Portland 2010^152,153) that utilizes nature-based solutions is emerging as a potential adaptation option. However, in some locations and for some impacts, it may be more efficient to remove or abandon infrastructure and find alternatives (for example, relocating communities and distributing water or energy systems). The knowledge and experience are just emerging to identify thresholds when such transformative decisions might be appropriate (Ch. 11: Urban, KM 3; Ch. 17: Complex Systems, KM 4).

Linkage Between Climate Change and Regional Risks

Over the last few decades, an increase in climate-related extreme events has led to an increase in the number of emergency room visits and hospital admissions. Warmer and drier conditions during summer have contributed to longer fire seasons.¹⁴⁰ Wildfire smoke can be severe, particularly in communities in the eastern Northwest.¹⁵⁴ Smoke events during 2004–2009 were associated with a 7.2% increase in respiratory hospital admissions among adults over 65 in the western United States.¹⁵⁵ In Boise, Idaho, 7 of the last 10 years have included smoke levels considered “unhealthy for sensitive groups” (including children) for at least a week during the fire season,¹⁵⁴ causing some cancellation of school-related sports activities (Ch. 13: Air Quality, KM 2).

During extreme heat events in King County, Washington, from 1990 to 2010, heat-related hospital admissions were 2% higher and deaths 10% higher than the average for that period,^156,157 with an increased demand for emergency medical services for children, outdoor laborers, and the elderly.¹⁵⁸ The state of Oregon has also recorded spikes in heat-related emergency room visits.¹⁵⁹ In particular, agricultural workers are at increased risks for heat-related injuries because they work outside during the summer harvest season.¹⁶⁰

In the last several years, the region has seen an increase in some infectious diseases. An increase in Lyme disease cases is associated with rising temperatures and changing tick habitat.¹⁶¹ The Washington Department of Health’s vector surveillance program has observed an earlier onset of West Nile virus-carrying mosquitoes, likely associated with higher temperatures, and an increasing number of human infections, with some resulting in fatalities.¹⁶² Before 1999, cryptococcal infections were limited to the tropics, but Cryptococcus gatti, the species that causes these infections, is now established in Northwest soil, with 76 cases occurring in Oregon in 2015.¹⁶³ The Oregon Health Authority recorded spikes in cases of Salmonella and E. coli during months with extreme heat in 2015.¹⁶³ A large outbreak of Shigellosis (a bacterial diarrheal disease) occurred in late 2015, affecting a large number of homeless people in the Portland Metro region; this outbreak was associated with unusually extreme precipitation.¹⁶⁴

Changes in drought conditions and increased water temperatures have increased the potential for freshwater harmful algal blooms in recreational waters,¹⁶⁵ although there is little capacity among state health departments to monitor and track harmful algal blooms. Toxins from marine harmful algal blooms can accumulate in shellfish, leading to illnesses for those who eat them.¹⁶⁶ In 2015, during the largest harmful algal bloom ever observed off the West Coast from California to Alaska, high levels of domoic acid led to the closure of shellfish harvesting in much of the Northwest (Box 24.7).¹⁶⁷

Children and youth, in general, will likely experience cumulative physical and mental health effects of climate change over their lifetimes¹⁶⁸ due to increased exposure to extreme weather events (such as heat stress, trauma from injury, or displacement) and increased toxic exposures (such as increased ground-level ozone pollution in urban areas or increased risk of drinking water contamination in rural areas). Beginning at the fetal development stage, environmental exposures to air or water pollution can increase the risk of impaired brain development,¹⁶⁹ stillbirth,¹⁷⁰ and preterm births.^171,172 Infants and children can be disproportionately affected by toxic exposures because they eat, drink, and breathe more in proportion to their body size.¹⁷³ Natural disasters, as well as gradual changes (like changing landscapes and livelihoods) caused by climate stressors, increase the risk of anxiety, depression, and post-traumatic stress disorder (PTSD).¹⁷⁴ Evidence shows that exposure to both pollution and trauma early in life is detrimental to near-term health, and an increasing body of evidence suggests that early-childhood health status influences health and socioeconomic status later in life.^175,176

Future Climate Change Relevant to Regional Risks

More frequent wildfires and poor air quality are expected to increase respiratory illnesses in the decades to come (Ch. 13: Air Quality, KM 2). Airborne particulate levels from wildfires are projected to increase 160% by mid-century under a lower scenario (RCP4.5),¹⁷⁷ creating a greater risk of smoke exposure through increasing frequency, length, and intensity of smoke events.¹⁷⁷

Projected increases in ground-level ozone (smog), small particulate matter (PM_2.5), and airborne allergens¹⁷⁸ can further complicate respiratory conditions (Ch. 13: Air Quality, KM 1). There is a well-documented link between exposure to air pollution and risk of heart attack, stroke, some types of cancer, and respiratory diseases,¹⁷⁹ all of which are leading causes of death in the Northwest.¹⁸⁰ The portion of each health condition attributed to air pollution is unknown, but the social and economic costs of these diseases are large. In Oregon, the medical costs associated with heart attacks in 2011 alone were over $1.1 billion, and those associated with stroke were $254 million ($1.2 billion and $269 million, respectively, in 2015 dollars).¹⁸¹

Increases in average and extreme temperatures are projected to increase the number of heat-related deaths.^182,183 Mid-century climate in Portland, Oregon, under a mid-high scenario (RCP6.0) may result in more than 80 additional heat-related deaths per year, although this figure does not account for future population growth or possible adaptations.¹⁸⁴

Future extreme precipitation events could increase the risk of exposure to water-related illnesses as the runoff introduces contaminants and pathogens (such as Cryptosporidium, Giardia, and viruses) into drinking water.¹⁸⁵ In the Puget Sound, under a mid-high emissions scenario (SRES A1B), local atmospheric heating of surface waters is projected to result in 30 more days per year that are favorable to algal blooms and an increased rate of bloom growth.¹⁸⁶

Income loss associated with climate impacts will likely increase the risk of people experiencing food insecurity (see Key Message 1).¹⁸⁷ As an example, in early 2016 a harmful algal bloom impacted the local economy in Long Beach, Washington, which is largely dependent on shellfish, tourism, and service industries. The local Food Bank recorded an almost 25% increase in the number of families requesting assistance in the six months that followed.¹⁸⁸ Climate-driven hardships can also affect mental health, resulting in outcomes ranging from stress to suicide.¹⁸⁹ Oregon, Washington, and Idaho all rank among the top 10 states in terms of prevalence of mental illness and lowest access to mental health care.¹⁹⁰ Serious mental illness costs the U.S. economy more than $193 billion in lost earnings each year ($224 billion in 2015 dollars).¹⁹¹ Tribes and Indigenous peoples face multiple physical and mental health challenges related to climate change, with impacts to subsistence and cultural resources (see Key Messages 2 and 5) (see also Ch. 15: Tribes, KM 2). Some of these health concerns are described in a recent project created by members of the Confederated Tribes of Warm Springs.¹⁹² Tracking climate stressors and training related to climate anxiety and post-disaster trauma is not widespread among the region’s health workforce.¹⁹³

Challenges, Opportunities, and Success Stories for Reducing Risk

Existing environmental health risks are expected to be exacerbated by future climate conditions,¹⁸⁷ yet over 95% of local health departments in Oregon reported having only partial-to-minimal ability to identify and address environmental health hazards.¹⁹⁴

With funding from the Centers for Disease Control and Prevention, Oregon has been able to make some headway on assessing climate change vulnerabilities¹⁹⁵ and recently released a statewide climate and health resilience plan.¹⁹⁶ Five local health jurisdictions in Oregon are some of the first in the country to complete local climate and health adaptation plans. Interventions to address community-identified priorities range from providing water testing for domestic well users in drought-prone areas to quantifying the health co-benefits of proposed transportation investments. The Washington Department of Health has also added a climate program to begin integrating climate considerations into the state’s public health system. In addition, the Drinking Water State Revolving Fund has made it possible for water system managers and utilities to apply for low interest loans that support resilience projects. Washington’s Marine Biotoxin Program, also housed within the Department of Health, operates an early warning system in partnership with academics, organizations, and citizen scientists to increase the geographic breadth and frequency of sampling for harmful algal blooms that could compromise the safety of shellfish. Public health practitioners in southeastern Idaho have formed a new working group with tribes, universities, local jurisdictions, businesses, and nonprofits to develop strategies for mitigating health impacts of wildfire smoke and water insecurity.

Together, Northwest states have launched the Northwest Climate and Health Network for public health practitioners to share resources and best practices. Idaho, Oregon, and Washington all have syndromic surveillance systems that provide near-real-time data from emergency room visits. These health data have the potential to be layered with climate and environmental data (such as temperature and air quality data), but such analysis has not been carried out on a broad scale.

Incorporating more health and wellness considerations into climate decision-making can increase a community’s overall resilience (Ch. 14: Human Health, KM 3). For example, preserving the ecological functions of an area can also promote tribal and Indigenous health, while investing in active transportation and green infrastructure can also improve air quality and increase physical activity.¹⁹⁷

Emerging Issues

Communities with higher rates of illness and death often have less adaptive capacity and are more vulnerable to climate stressors.¹⁹⁸ Many people living in the Northwest already struggle to meet basic needs that could serve as protective factors—and these numbers could increase. For example, roughly 1 in 5 children in the region live in a food-insecure household^199,200,201 and are already at higher risk of poor health outcomes like asthma and diabetes.²⁰² Both the states of Washington and Idaho have had some of the largest increases in homeless populations in the United States, and in 2016, Oregon had the highest rate of unsheltered homeless families with children.²⁰³ People lacking adequate shelter face increased climate risks (such as direct exposure to extreme heat or winter storms), while also having increased vulnerability (such as poorer health and less access to resources).

Displacement and increased migration to the Northwest could place increasing pressures on housing markets, infrastructure, and health and social service systems.¹²⁸ However, the role of climate as a driver for migration to the Northwest is speculative; current population forecasts do not yet account for climate factors.²⁰⁴

Public health leaders in the Northwest are working to modernize health systems to better respond to and prepare for complex and emerging health risks. Coordinated Care Organizations (CCOs) in Oregon, which serve as Medicaid insurance providers, are beginning to invest in certain climate protections for members. For example, some are covering the cost of air conditioning units for patients at risk of heat-related illnesses, ensuring patients can remain in their homes.²⁰⁵ More studies would be needed to fully account for the cost savings associated with these kinds of health-related services.

Linkage Between Observed Climate and Regional Risks

Because people care about the place they live, a focus on places serves to highlight the local material and symbolic contexts in which people create their lives and through which those lives derive meaning.^206,207 This is true for communities across the Northwest whether or not they are on the frontline of dealing with climate change. While there are many types of frontline communities (those communities likely to experience climate impacts first and worst) in the region, this chapter highlights three sets of communities: tribes (Ch. 15: Tribes), farmworkers, and low-income populations in urban and rural (Ch. 10: Ag & Rural) environments.

The effects of climate variability and extreme events are not felt equally across communities in the Northwest. Frontline communities have higher exposures, are more sensitive, and are less able to adapt to climate change for a variety of reasons (Ch. 14: Human Health, KM 1),^187,208,209 including enhanced occupational exposure,²¹⁰ dependence on natural and cultural resources (Ch. 15: Tribes, KM 1),¹²⁴ fewer economic resources,²⁰⁹ other demographic factors,^211,212 and gender.²¹³ In addition, frontline communities frequently must overcome cumulative exposures¹²⁵ and intergenerational and historical trauma.^125,214 It is the interconnected nature of legacy exposure, enhanced exposure, higher sensitivity, and less capability to adapt that intensifies a community’s climate vulnerability.^187,215,216 Climate change can affect the health, well-being, and livelihoods of these communities directly by increasing the risk of acute health impacts, such as physical injury during severe weather,^189,209 and indirectly through chronic impacts, such as food insecurity or mental health conditions like PTSD (see Key Message 4) (see also Ch. 15: Tribes, KM 2; Ch. 14: Human Health, KM 1).

Future Climate Change Relevant to Regional Risks

Frontline communities generally prioritize meeting existing basic needs, such as shelter, food, and transportation. While climate-related risks vary from community to community, neighborhood to neighborhood, and even person to person, for frontline communities, climate variability, change, and extreme events can exacerbate existing risks, further limiting their ability to meet basic needs.²¹⁷

Northwest tribes directly depend on natural resources, both on and off reservations, and are among the first to experience climate impacts. In the United States, the history of colonization, coupled with ongoing management barriers (such as land fragmentation and limited authority and control over natural resources) has led to many challenges for tribal and Indigenous climate adaptation (see Box 24.5) (see also Ch. 15: Tribes, KM 3).^124,218 The loss or reduced availability of First Foods (Key Message 2) can have broad physical, cultural, and spiritual impacts, including diabetes, heart disease, mental health impacts, and loss of cultural identity.^125,209 This is likely to be coupled with mental health impacts associated with intergenerational and historical trauma, alcohol abuse, suicide, and other impacts (see Key Message 2) (see also Ch. 15: Tribes, KM 2).²⁰⁹

Farmworkers are vital to the region, yet they often earn very low wages and face discrimination and workplace hazards. Farmworkers and their families often deal with both chronic and acute health impacts because of the high cost of healthcare and physically demanding work environments. Overall, farmworkers, who are largely immigrant laborers from Mexico, Central America, and South America, face distinct challenges and are more vulnerable due to structural causes that can lead to exploitation, discrimination, and violence.²¹⁹ Climate change is projected to exacerbate these existing stressors.

While the Northwest is not typically considered a high-risk area for heat-related illness, heat waves (defined as 5-day, 1-in-10-year events) across the country are projected to increase in frequency and intensity.³ In the Northwest, nighttime heat waves (defined as 3-day, 1-in-100-year events) have a greater influence on human health than daytime heat waves ²²⁰ and have increased in frequency since 1901.²²¹ These changes are projected to make heat-related illness more common in the future. Farmworkers can be particularly vulnerable to heat-related illness due to occupational exposure (heavy exertion and working outdoors)²¹⁰ and to air quality concerns associated with wildfires, yet they often do not seek healthcare because of high costs, language barriers, and fear of deportation.²²² Working conditions, as well as cooling and hydration practices, vary across the region.²²³

In urban environments, economically disadvantaged communities and communities of color live in neighborhoods with the greatest exposure to climate and extreme weather events ²²⁴ and are, therefore, disproportionately affected by climate stressors.^225,226 Urban heat islands, worsening air quality,²²⁷ less access to transit, increasing demands for food and energy, and proximity to pollution sites can lead to injury, illness, and loss of life for the urban poor (Key Message 4).^225,228 For instance, in the Northwest, increased risk of heat-related illnesses and deaths has been associated with socioeconomic status, age, race, and occupation (for example, outdoor labor).^156,182,229

Challenges, Opportunities, and Success Stories for Reducing Risk

Many frontline communities are taking actions that begin to address these challenges. Indigenous peoples and Northwest tribes have demonstrated a high degree of resilience by adapting to changing environmental and social conditions for thousands of years (Ch. 15: Tribes).¹²⁴ The strong social networks and connectivity, present in many tribes and Indigenous communities, can reduce vulnerability to climate change (Ch. 15: Tribes, KM 3).²³⁰ Efforts to enhance communication and strengthen network connections between tribes and their partners can be seen across the region.

Acknowledging the risk of heat-related illness for outdoor workers, the state of Washington issued rules requiring employers to make specific changes to job sites during the summer season (from May 1 through September 30). For temperatures above certain thresholds, the employer is required to provide at least one quart of water per employee per hour, relieve employees from duty if they are showing signs of heat-related illness, and provide training for employees and supervisors about heat-related illness.²³²

Economically disadvantaged populations and communities of color often face multiple barriers to participating in public processes where decisions about future climate-related investments are made. Organizations representing these frontline communities have found some success prioritizing leadership development through workshops and training that enable new and emerging voices to be heard in more formal policy settings. Engagement has partly been made possible by providing transportation, childcare, meals, and accessibility and by using a relational worldview and trauma-informed approach to community capacity-building. Cities and counties have also made concerted efforts at the policy level to explicitly acknowledge and address race and social inequities alongside environmental concerns.^{147,228,233,234,235} Example actions include targeting investments in frontline communities and providing job training and employment opportunities that help limit displacement and enhance resilience.¹⁴⁷

Emerging Issues

There is an emerging understanding of the importance of not only prioritizing climate change preparedness efforts in frontline communities but also involving and empowering these groups in the decision-making and implementation of climate change plans and actions.

The physical and psychological connections people have with natural resources are complex, and additional research would aid understanding of how changing climate conditions are likely to affect not only those natural resources but also the people who depend on them. How intersecting vulnerabilities, driven by a confluence of climatic, social, and economic factors, will compound and accelerate risks in frontline communities is not yet fully understood (Ch. 17: Complex Systems, KM 1). Additional research would help to measure and evaluate how supporting frontline communities in the implementation of community-identified strategies might improve outcomes and increase not only climate resilience but also equity and economic vitality in the Northwest and across the country.