[7] Feds' Report Outlines NW Climate Change Impacts

The Northwest has already begun to see the impacts of climate change, according to a report issued June 16 by the U.S. Global Change Research Program, a group of 13 federal agencies overseen by the executive office of the President. The report is an effort to aggregate federal research on climate change. It offered regional summaries, including one for the Northwest.

"Impacts related to changes in snowpack, streamflows, sea level, forests, and other important aspects of life in the Northwest are already underway, with more severe impacts expected over coming decades," according to the report, which said temperatures in the Northwest rose about 1.5º F over the past century.

Average snowpack has declined 25 percent over the past 40 to 70 years in the Cascade Mountains and may decline another 40 percent by the 2040s, the report states.

"Throughout the region, earlier snowmelt will cause a reduction in the amount of water available during the warm season." A shift in the timing of streamflows has already been observed, it adds, with "the peak of spring runoff shifting from a few days earlier in some places to as much as 25 to 30 days earlier in others."

Increasing amounts of rain during winter, rather than snow, will lead to more winter flooding. There are also implications for regional water supply infrastructure, since the region's system presumes that most of the water needed during summer can be stored as snowpack. Storage capacity in Columbia Basin reservoirs is only 30 percent of annual runoff, the report notes, and many small suppliers west of the Cascades store less than 10 percent of their annual flows.

The report summarizes other impacts for the Northwest, including increased insect outbreaks and wildfires. Salmon and other fish species "will experience additional stresses" due to rising water temperatures and declining summer streamflows, and sea-level rise along "vulnerable coastlines will result in increased erosion and the loss of land.

"Among the most vulnerable parts of the coast is the heavily populated south Puget Sound region, which includes the cities of Olympia, Tacoma, and Seattle, Washington." -Ben Tansey

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