News From My Backyard: Pacific Northwest Faces Climate Change Impacts

[The following is an exerpt from the Oregonian's coverage of the IPCC 4th Assessment report released today (see previous post). It discusses regional climate change impacts to the Pacific Northwest. Just bringing this all home...]

Why we're vulnerable

Although the IPCC's "Summary for Policymakers" does not mention the Northwest, Mote said the implications are clear for a region dependent on winter snowpack for irrigation, power, fish and urban water supplies.

Mote -- the lead author of the yet-to-be-released full report's chapter about snow and ice changes -- said previous studies have shown that the Cascades' snowpack has been decreasing since the 1930s, resulting in lower summer streamflows.

"Those are a primary consequence of a warming climate," said Mote, "and poses challenges for water resource managers, agriculture and hydropower."

Mote, the state climatologist for Washington, said the past 10 years in the Northwest have been the warmest since record-keeping began in the 19th century.

Separately, researchers at Portland State University have in recent years tracked and verified the dramatic retreat of glaciers on Mount Hood and other Cascade peaks.

[Mt Hood's once extensive glaciers and the extent of remaining summer snowpack have retreated significantly in just the past two decades, as documented by these photos from Gary Braasch (image source: WorldViewOfGlobalWarming.com)]

Ruby Leung, a climate modeler at the Pacific Northwest National Laboratory in Richland, Wash., agreed that the region will be one of the nation's most hard-hit areas if warming projections are correct. Leung is a contributor to a chapter in the full IPCC report about regional climate projections.

Leung said previous studies by her and others indicate there will be a significant reduction in snowpack by 50 percent to 70 percent in the West's coastal mountains, including the Cascades.

There also will be a change in the type of precipitation in the winter, with more of it falling as rain rather than snow. That trend is already especially clear in the Northwest, where temperatures are not far below freezing and a slight increase could turn snow to rain.

Much of the rain will come in very heavy storms. That's because warmer temperatures allow the atmosphere to hold more moisture, which it releases in bigger downpours. That can lead to winter flooding and smaller streamflows in rivers and streams during the summer.

Ron Neilson, a U.S. Forest Service climate scientist in Corvallis who has been a primary author on previous IPCC reports, said the new conclusions support many earlier scientific findings.

"In some ways that's comforting," he said. But at the same time the speed at which the climate is shifting has surprised many of the researchers who study it. "We're rather abashed at how fast things are changing." But he said it's clear the public has begun to notice the climate changing in their own backyards.

"When records that have been standing for 100 years are falling right and left, people are sitting up and taking notice," he said.

Neilson added that land managers and other public officials must realize that the climate and the forests, wildlife and people who depend on it will face a shifting future as greenhouse gases push climate to new extremes.

Today's IPCC report is the group's fourth assessment -- and first in six years -- since the group was established, in 1988, by the World Meteorological Organization and the United Nations Environment Program.

Luckily for us Oregonians, we've got plenty of great climate solutions at our disposal in this year's legislature. Check out this previous post for a summary of all of the renewable energy bills being proposed.