UW report: Climate change to boost Puget Sound sea levels

SEATTLE – The Puget Sound region is projected to face more intense flooding, rising sea levels, heavier downpours and thinner winter snowpack as temperatures continue to warm in coming decades, according to a report released Tuesday by the University of Washington.

Under the most optimistic projections for future greenhouse gas emissions, the average air temperatures in Puget Sound are projected to rise by 2.9 to 5.4 degrees Fahrenheit by the 2050s, according to the report by the school’s Climate Impacts Group.

“When you look at the projected changes, it’s dramatic,” said Guillaume Mauger, lead author and a UW research scientist.

Many communities, agencies and organizations are taking steps to respond and adapt to the changes, and those actions will help shape the future consequences of climate change, the report says.

The Swinomish and Jamestown S’Klallam tribes have assessed how climate change will affect their resources and are devising strategies to address those changes. Meanwhile, government officials in Tacoma, Olympia, Seattle and King County have mapped zones where sea level rise is expected to inundate areas.

Anacortes factored climate change into its new wastewater treatment plant, and the Port of Bellingham is redeveloping a 228-acre site near downtown to include features that would help buffer against rising seas.

Ten UW authors contributed to the 279-page climate report, drawing on peer-reviewed science, agency reports and other data to paint a picture of impacts.

The Puget Sound Institute commissioned the report, which covers a watershed that stretches from the Canadian border to northern Lewis County and toward the tip of the Northwest coast.

It says larger and more frequent winter flooding events are expected, as well as increased precipitation falling as rain rather than snow.

Ocean waters are absorbing more carbon dioxide and becoming more acidic, with consequences for marine ecosystems and the state’s shellfish industry.

Ocean levels are expected to increase by 4 to 56 inches by 2100, the report says. Sea level rise is projected for all locations except Neah Bay, where authors couldn’t conclusively rule out a decline in the sea level.