Mote et al 2003 preparing for climate change salmon water and forests

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Mote, P. W., Parson, E. A., Hamlet, A. F., Keeton, W. S., & al, e. (2003). Preparing for climatic change: The water, salmon, and forests of the pacific northwest. Climatic Change, 61(1-2), 45-88. doi:


  • A analysis of retrospective climate variability and natural resource response for the purpose of anticipating imminent greenhouse effects.
  • Three low resolution models were used to compare scenarios while maximizing confidence.
  • Analyses implications and strategies are discussed in anticipation of a regional 1.5 C increase by 2020s and 2.3 C increase by 2040s.
  • Foremost impacts will be reduced snowpack, and increased precipitation except during dry summers (additional detail in Mauger et al 2015 puget sound climate change
  • PNW population has doubled since 1970s which is twice the national rate.
  • The natural variability of El Nino (ENSO) and the Pacific Decadal Oscilation (PDO) are around 1 C temperature and 20% increase in rainy season precipitation, and serves as a surrogate for future normal climate, and for detecting patterns of impact.
  • Model confidence is generally higher for temperature than for precipitation.
  • The Columbia River is the regions largest source of irrigation and energy with 250 reservoirs and 100 hydroelectric projects, and is among the most developed in the world, with limited room for expansion.
  • Allocation of water has historically been to prioritize availability of flow for winter hydroelectric production on "firm contracts". This conflicts with "fish-first" rules that prioritize summer stream flow. Severe water allocation conflicts between hydropower, summer irrigation, and fish low flow are anticipated by mid-century in the Columbia Basin.
  • West side systems are particularly susceptible to winter flooding, and summer flow depends on the area to catchment ratio to transfer winter water to summer flow.
  • Population growth demands are similar in scale to loss of supply due to predicted climate change.
  • Salmon have been lost from 40% of their historical breeding range in CA, WA, ID, BC, but decline is greatest in southern extent, in interior basins, and among life histories with longer freshwater rearing periods.
  • Due to a mixture of factors, stock production in the PNW range is generally lower during warm-phase, with both freshwater and marine mechanisms as potential factors (this pattern reverses in Alaska).
  • West side forests have very low fire frequency which allows for fuel build-up. During unusual warming this creates the opportunity for catastrophic stand replacing fires. Existing fire records seem to suggest a strong correlation between climate cycle, fire area, and drought. Interactions between the northward expansion of insect pests, increased drought stress, and fire regime will likely be important.
  • Low reservoir levels used for municipal water supply can require improved purification (for example Seattle's ozone purification plant following the 1992 drought).
  • "If it has been an uphill battle persuading resource managers that seasonal forecasts can add valuable knowledge to the decision process, it has been a Sisyphean task to effect meaningful adaptations to climatic change" p76
  • There are three basic strategies for water supply management: increase supply, reduce demand, increase flexibility.
  • Supply includes new storage, increased groundwater recharge, or increased use of non-potable sources.
  • Demand side management is less politically tenable, there is no prioritization among various water demands, and so limited mechanisms for optimization of allocation. Efficiency has increased. Use-it-or-lose-it water laws create disincentives to conservation because reduction in use can lead to relinquishment of rights.
  • Flexibility is easier for high-flow impacts, because of relatively centralized control of flood systems, where as multi-user conflicts of water during low-flow scarcity, reduces responsiveness of systems.
  • Cycles of expansion during cool cycles, followed by droughts, creates a natural sequence of crisis.
  • A strong strategy may be water law reform that helps create market-based adjustments.
  • These opportunities for systematic adjustment typically come with crisis (with Yakima and Kalamath as examples).