A.K. Snover

Preparing for Climatic Change: The Water, Salmon, and Forests of the Pacific Northwest

The impacts of year-to-year and decade-to-decade climatic variations on some of the Pacific Northwests key natural resources can be quantified to estimate sensitivity to regional climatic changes expected as part of anthropogenic global climatic change. Warmer, drier years, often associated with El Niño events and/or the warm phase of the Pacific Decadal Oscillation, tend to be associated with below-average snowpack, streamflow, and flood risk, below-average salmon survival, below-average forest growth, and above-average risk of forest fire. During the 20th century, the region experienced a warming of 0.8 °C. Using output from eight climate models, we project a further warming of 0.5–2.5 °C (central estimate 1.5 °C) by the 2020s, 1.5–3.2°C (2.3 °C) by the 2040s, and an increase in precipitation except in summer. The foremost impact of a warming climate will be the reduction of regional snowpack, which presently supplies water for ecosystems and human uses during the dry summers. Our understanding of past climate also illustrates the responses of human management systems to climatic stresses, and suggests that a warming of the rate projected would pose significant challenges to the management of natural resources. Resource managers and planners currently have few plans for adapting to or mitigating the ecological and economic effects of climatic change.

An approach to designing a national climate service

Climate variability and change are considerably important for a wide range of human activities and natural ecosystems. Climate science has made major advances during the last two decades, yet climate information is neither routinely useful for nor used in planning. What is needed is a mechanism, a national climate service (NCS), to connect climate science to decision-relevant questions and support building capacity to anticipate, plan for, and adapt to climate fluctuations. This article contributes to the national debate for an NCS by describing the rationale for building an NCS, the functions and services it would provide, and how it should be designed and evaluated. The NCS is most effectively achieved as a federal interagency partnership with critically important participation by regional climate centers, state climatologists, the emerging National Integrated Drought Information System, and the National Oceanic and Atmospheric Administration (NOAA) Regional Integrated Sciences Assessment (RISA) teams in a sustained relationship with a wide variety of stakeholders. Because the NCS is a service, and because evidence indicates that the regional spatial scale is most important for delivering climate services, given subnational geographical/geophysical complexity, attention is focused on lessons learned from the University of Washington Climate Impacts Groups 10 years of experience, the first of the NOAA RISA teams.

High-accuracy measurements of total dissolved inorganic carbon in the ocean: comparison of alternate detection methods

High-accuracy measurements of total dissolved inorganic carbon in the ocean are currently performed using an automated coulometric system based on that described by Johnson et al. (1987). These measurements require highly-trained technicians and the manipulation of expensive and hazardous chemicals. We tested an alternate detection method based on non-dispersive infra-red analysis. All of the dissolved carbonate species from a seawater sample were extracted as CO2 gas by acidification and nitrogen stripping. The CO2 gas was then quantitatively detected with either a coulometric system or an infra-red analyzer. The reproducibility of the two detection methods is similar. Although the infra-red system requires further testing, it holds promise as an alternative to coulometry. The detection of the CO2 gas by infra-red analysis presents several advantages over coulometric detection: it simplifies and reduces the cost of the measurements, shortens the analysis time, reduces the sample size requirement by at least a factor of five, and allows us to consider complete automation of the system for underway surface seawater measurements.

Incorporating Climate Science in Applications of the U.S. Endangered Species Act for Aquatic Species

Aquatic species are threatened by climate change but have received comparatively less attention than terrestrial species. We gleaned key strategies for scientists and managers seeking to address climate change in aquatic conservation planning from the literature and existing knowledge. We address 3 categories of conservation effort that rely on scientific analysis and have particular application under the U.S. Endangered Species Act (ESA): assessment of overall risk to a species; long-term recovery planning; and evaluation of effects of specific actions or perturbations. Fewer data are available for aquatic species to support these analyses, and climate effects on aquatic systems are poorly characterized. Thus, we recommend scientists conducting analyses supporting ESA decisions develop a conceptual model that links climate, habitat, ecosystem, and species response to changing conditions and use this model to organize analyses and future research. We recommend that current climate conditions are not appropriate for projections used in ESA analyses and that long-term projections of climate-change effects provide temporal context as a species-wide assessment provides spatial context. In these projections, climate change should not be discounted solely because the magnitude of projected change at a particular time is uncertain when directionality of climate change is clear. Identifying likely future habitat at the species scale will indicate key refuges and potential range shifts. However, the risks and benefits associated with errors in modeling future habitat are not equivalent. The ESA offers mechanisms for increasing the overall resilience and resistance of species to climate changes, including establishing recovery goals requiring increased genetic and phenotypic diversity, specifying critical habitat in areas not currently occupied but likely to become important, and using adaptive management. Incorporación de las Ciencias Climáticas en las Aplicaciones del Acta Estadunidense de Especies en Peligro para Especies Acuáticas.

Choosing and using climate-change scenarios for ecological-impact assessments and conservation decisions.

Increased concern over climate change is demonstrated by the many efforts to assess climate effects and develop adaptation strategies. Scientists, resource managers, and decision makers are increasingly expected to use climate information, but they struggle with its uncertainty. With the current proliferation of climate simulations and downscaling methods, scientifically credible strategies for selecting a subset for analysis and decision making are needed. Drawing on a rich literature in climate science and impact assessment and on experience working with natural resource scientists and decision makers, we devised guidelines for choosing climate-change scenarios for ecological impact assessment that recognize irreducible uncertainty in climate projections and address common misconceptions about this uncertainty. This approach involves identifying primary local climate drivers by climate sensitivity of the biological system of interest; determining appropriate sources of information for future changes in those drivers; considering how well processes controlling local climate are spatially resolved; and selecting scenarios based on considering observed emission trends, relative importance of natural climate variability, and risk tolerance and time horizon of the associated decision. The most appropriate scenarios for a particular analysis will not necessarily be the most appropriate for another due to differences in local climate drivers, biophysical linkages to climate, decision characteristics, and how well a model simulates the climate parameters and processes of interest. Given these complexities, we recommend interaction among climate scientists, natural and physical scientists, and decision makers throughout the process of choosing and using climate-change scenarios for ecological impact assessment. Selección y Uso de Escenarios de Cambio Climático para Estudios de Impacto Ecológico y Decisiones de Conservación.

Climate Impacts on Washington's Hydropower, Water Supply, Forests, Fish, and Agriculture

The Climate Impacts Group periodically updates its scenarios of Pacific Northwest climate change and climate impacts as warranted by developments in global climate models and improvements in regional modeling capabilities. For the most current scenarios, see Figures Figure 1. Accumulation of greenhouse gases in the atmosphere increases global mean surface The climate is changing. Human activities, especially those related to fossil fuel combustion, have and will continue to change the composition of the atmosphere. Consequently, climate conditions in Washington during the 21 st century will likely be different than those experienced in the past. • All climate models project that temperatures will increase during the 21 st century. The projected increases exceed the year to year variability in temperature experienced during the 20 th century and occur across all seasons. • Many climate models project a slight increase in precipitation, especially during the fall and winter months during the 21 st century. However, natural year-to-year and decade-to-decade fluctuations in precipitation are likely to be more noticeable than longer term trends associated with climate change. Washington will probably continue to experience distinct periods, perhaps decades long, of relatively wet and relatively dry conditions. Washingtons economy and natural resources are sensitive to changes in climate. Management of hydroelectric power production, water supply systems, flood and storm management, forests, fisheries, and agriculture is predicated on observed patterns and extremes in temperature and precipitation. Each of these sectors has adapted to the timing and length of the seasons, the range of temperatures, and the amount and frequency of precipitation that has been experienced in the past. As temperature increases and precipitation patterns potentially change during the 21 st century, current management practices may not achieve the results for which they are designed. Hydroelectric Power Production Increasing temperatures, decreases in snowpack, and shifts in the amount and timing of streamflow will likely reduce winter electricity demands and increase winter electricity generation. Conversely, summer demands are likely to increase overall while summer generation is likely to decrease. Any changes in annual hydropower generation are highly dependent on future changes in winter precipitation, and will probably be determined by the characteristics of future wet or dry cycles, the timing and intensity of which remain uncertain. Municipal and Industrial Water Supplies Increasing temperatures and decreased summer flows could make it more difficult for water suppliers to meet the needs of consumers and in-stream flow requirements, especially in snowmelt-fed …

Uncertain Future: Climate Change and Its Effects on Puget Sound

• Figure 3, Average daily freshwater flow into Puget Sound (p. 17): The time interval used to construct the orange curve in Figure 3 was 1948-1967. Please also note this figure is incorrectly numbered as a second Figure 3. • Figure 4, Simulated average runoff for the Puget Sound basin (p. 17): The warming used in the hydrologic simulation of future climate for Figure 4 was +2.3°C (4.1°F). • Figure 6, Future sea level rise scenarios for various locations in Puget Sound (p. 21): o The endnote reference for Figure 6 (p.21) should be 81, i.e., Canning 1991. o The sea level rise curves slightly overpredict the highest rates of rise and slightly underpredict the lowest rates of rise. The correct sea level rise amounts for 2100 from this analysis are Tacoma 0.94 m, Seattle 0.83 m, Friday Harbor 0.68 m, and Neah Bay 0.41 m. Additionally, the reader should note the following point of clarification about the Pacific Northwest warming trends shown in Figure 3 on page 14: • The trend shown in Figure 3 shows changes in average temperature relative to the decade of the 1990s while the projected warming stated in the text on p.14 is relative to 1970-1999 average temperature. For the trend line in the figure to match the numbers provided in the text, the lines in the figure would be bumped up by 0.21°C (0.38°F).

Learning from and adapting to climate variability in the Pacific Northwest

In recent years, Pacific Northwest (PNW) natural resource managers, planners, and policymakers have been increasingly utilizing climate information to prepare for and adapt to climate fluctuations on seasonal/interannual to decadal timescales. While some of this progress reflects improvements in climate forecasting, much can be attributed to efforts undertaken by the Climate Impacts Group (CIG) to increase regional resilience to climate fluctuations, including: • developing regionally-specific integrated understanding of the consequences of climate fluctuations for PNW natural resources, • developing seasonal to interannual forecast tools and climate change scenarios for integrating climate impacts into resource planning, and • developing the strategies and relationships required to bring the academic research and the resource management/policymaking communities together for mutually beneficial interaction.

Regional Climate Change Primer

Precipitation: Precipitation changes in the PNW over the last century have been dominated by natural variations between relatively dry and relatively wet periods, rather than by a trend in one direction. For example, a slight increase in winter precipitation occurred from 1916 to 2003, largely resulting from an extensive drought in the 1930s. On the other hand, a strong negative trend in winter precipitation occurred from 1947 to 2003.

The Climate Impacts Group: Piloting climate services for the Pacific Northwest

The Climate Impacts Group (CIG) at the University of Washington (funded under NOAA’s Regional Integrated Science and Assessments Program) works to increase the resilience of the Pacific Northwest (PNW) to fluctuations in climate. CIG develops, tests, and introduces natural resources planning and decisionmaking tools that are based on seasonal/inter-annual climate forecasts and/or projections of anthropogenic climate change derived from global climate models. Over recent years, CIG has been evolving towards a regional “climate service,” that is, an information broker providing users with the information about climate impacts and response strategies they need to make climate forecasts relevant to planning and decision making. Here we describe CIG’s scope, research approach, and strategies and objectives for developing and maintaining long-term relationships with stakeholders; highlight CIG’s annual water resources planning workshops; and introduce new products and ongoing research on applications of climate forecasts for PNW natural resource management.