Top Northwest risks

The Northwest is facing increased risks from the decline of forest health, earlier snowmelt leading to low summer stream flows, and an array of issues facing the coastal region, according to a new climate assessment report.

OSU’s Philip Mote, director of the Climate Change Research Institute (OCCRI) at Oregon State University and one of three editors of a 270-page report (as well as the 1999 report), said the document incorporates a lot of new science as well as some additional dimensions – including the impact of climate change on human health and tribal issues. A summary of the report is available online at: http://occri.net/reports />

Amy Snover, director of the Climate Impacts Group at the University of Washington, said there are a number of issues facing the Northwest as a result of climate change.

“As we looked across both economic and ecological dimensions, the three that stood out were less snow, more wildfires and challenges to the coastal environment and infrastructure,” said Snover, who is one of the editors on the report.

The report outlines how these three issues are affected by climate change.

“Studies are showing that snowmelt is occurring earlier and earlier and that is leading to a decline in stream flows in summer,” Mote said. “Northwest forests are facing a huge increase in wildfires, disease and other disturbances that are both direct and indirect results of climate change. And coastal issues are mounting and varied, from sea level rise and inundation, to ocean acidification. Increased wave heights in recent decades also threaten coastal dwellings, roads and other infrastructure.”

OCCRI’s Meghan Dalton, lead editor on the report, notes that 2,800 miles of coastal roads are in the 100-year floodplain and some highways may face inundation with just two feet of sea level rise. Sea levels are expected to rise as much as 56 inches, or nearly five feet, by the year 2100.

Earlier snowmelt is a significant concern in the Northwest, where reservoir systems are utilized to maximize water storage. But, Dalton said, the Columbia River basin has a storage capacity that is smaller than its annual flow volume and is “ill-equipped to handle the projected shift to earlier snowmelt…and will likely be forced to pass much of these earlier flows out of the system.”

The earlier peak stream flow may significantly reduce summer hydroelectric power production, and slightly increase winter power production.

Mote said new research has led to improved climate models, which suggest that the Northwest will warm by a range of three to 14 degrees (Fahrenheit) by the year 2100. “The lower range will only be possible if greenhouse gas emissions are significantly reduced.” In contrast, the Northwest warmed by 1.3 degrees from the period of 1895 to 2011.

The Northwest has not to date been vulnerable to many climate-related health risks, the report notes, but impacts of climate change in the future are more likely to be negative than positive. Concerns include increased morbidity and mortality from heat-related illness, air pollution and allergenic disease, and the emergence of infectious diseases.

Snover said that the climate changes projected for the coming decades mean that many of the assumptions “inherent in decisions, infrastructure and policies – where to build, what to grow where, and how to manage variable water sources to meet multiple needs – will become increasingly incorrect.

“Whether the ultimate consequences of the climate impacts outlined in this report are severe or mild depends in part on how well we prepare our communities, economies and natural systems for the changes we know are coming,” Snover said.

Image above: Collier Glacier in the Oregon Cascade Range once filled this valley - note marks on North Sister, at left, from its maximum size more than 100 years ago. It’s now shrunk to less than half of its previous mass. Photo by OSU.

McKenzie River Reflections