Northwest vulnerable to global warming

Wednesday, July 25, 2007 11:16 AM PDT

SEATTLE — Rising sea levels brought on by global warming will erode Puget Sound beaches, inundate tidal flatlands and harm salmon habitat, the National Wildlife Federation said in a report released Tuesday.

The study, which focused on 11 coastal habitats in Washington and Oregon, examines the impact of rising sea-levels on the diverse geography of the Pacific Northwest. The possible effects vary widely: from limited damage in the Tacoma area because of dikes around the Puyallup River to an 81 percent decline in Olympia-area beaches where fresh water and salt water mix. The report expects about 19 square miles of dry land in the Willapa Bay, Columbia River and Tillamook Bay area in northwestern Oregon to be lost, along with extensive areas of tidal flats and beaches. Salt water is expected to move inland.

If the world’s oceans rise by 0.69 meters (27.3 inches) by 2100, as the U.S.-sponsored Intergovernmental Panel on Climate Change has predicted, about 65 percent of beaches around the Pacific Northwest stand would be lost to erosion, the Wildlife Federation estimated.

As much as 44 percent of tidal flats are expected to disappear in the next 100 years; 13 percent of inland fresh marshes and 25 percent of tidal fresh marshes will be lost; swamps will be inundated with salt water; and marsh will convert to tidal flats, the report said.

The impact of these habitat changes on the fish and wildlife living on or near Pacific Northwest beaches and estuaries is expected to vary.

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‘‘Some species may be able to respond to changes by finding alternative habitats or food sources, but others will not,’’ the report states, adding that the impact depends on how fast the water rises.

Changes in tidal wetlands could diminish salmon habitat, while migratory birds looking for a snack on tidal flats or coastal marshes may find the cupboard bare. The impacts will also affect other species that depend on coastal animals for their food, such as orcas that eat salmon.

Other impacts of global warming, such as increased rainfall, higher water temperatures and lower average snowpack, will also affect wildlife habitat. Algal blooms could increase, oxygen levels could drop and inland water salinity could increase, the report said.

The Wildlife Federation hopes its study will help give coastal decision-makers some of the information they need to plan ways to manage the impacts of sea-level rise on wildlife.

‘‘By taking a longer-term, more comprehensive approach to managing and protecting the coastal resources of the Pacific Northwest, we have a real opportunity to prevent the worst-case scenarios from occurring and ensure that the region’s treasured natural heritage will endure for generations to come,’’ the report said.

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