Joe Casola, Climate Impacts Group, University of Washington
Michael Chang, Makah Tribe
Jennifer Cuhaciyan, Bureau of Reclamation
Meghan Dalton, Oregon State University
Scott Lowe, Boise State University
Gary Morishima, Quinault Indian Nation
Philip Mote, Oregon State University
Alexander (Sascha) Petersen, Adaptation International
Gabrielle Roesch-McNally, USDA Forest Service
Emily York, Oregon Health Authority
Beatrice Van Horne, USDA Forest Service, Northwest Climate Hub
Natalie Bennett, Adaptation and Assessment Analyst
Christopher W. Avery, Senior Manager
Susan Aragon-Long, Senior Scientist
<b>May</b>, C., C. Luce, J. Casola, M. Chang, J. Cuhaciyan, M. Dalton, S. Lowe, G. Morishima, P. Mote, A. Petersen, G. Roesch-McNally, and E. York, 2018: Northwest. In <i>Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment</i>, Volume II [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 1036–1100. doi: 10.7930/NCA4.2018.CH24
Climate change is already affecting the Northwest’s diverse natural resources, which support sustainable livelihoods; provide a robust foundation for rural, tribal, and Indigenous communities; and strengthen local economies. Climate change is expected to continue affecting the natural resource sector, but the economic consequences will depend on future market dynamics, management actions, and adaptation efforts. Proactive management can increase the resilience of many natural resources and their associated economies.
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
Figure 24.3: Natural Resource Industry Jobs and Sales Revenues
Figure 24.3: Natural resources are a key part of the Northwest economy. Climate change is putting natural resource sector jobs and sales revenues at risk. Jobs and sales figures include the agriculture, forestry, and fisheries sectors only, and are presented based on 2015 data for Idaho, Oregon, and Washington.17 Source: U.S. Forest Service and Boise State University.
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
Supplemental Watering of Livestock During Drought
Figure 24.4: Supplemental watering of livestock in Eastern Oregon during the 2015 drought. Photo credit: Sonia A. …
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
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