Global Warming Could Put Northwest in Hot Water

by Patrick Mazza
Climate Solutions

Global warming can seem such a vast, complex issue. It's global, after all. But when prospective impacts are brought closer to home, its grave import becomes clear.

One way to grasp the significance of global warming for the Northwest is to ask, "How important is water here?" The answer is obvious: Water is the defining element of this region. Great forests, salmon runs, snowcapped mountains, and rivers supply abundant water for cities, power, and farms. We consider these to be enduring features of Northwest life. But each is dependent on the right amount and quality of water arriving at the right time. If we disturb the waters, it spells trouble.

Such disruption is the largest potential danger global warming poses for the Northwest. With average regional temperatures projected to increase 5 degrees Fahrenheit by around 2050, huge impacts on water are in sight. As winters warm, the average snowline on the Cascades range is expected to rise from its current 3,000 feet to 4,100 by around mid-century. The ski season could be shortened by a month, and ski runs might not reach the base of existing chair lifts. But that problem pales compared with an expected loss of half the region's snowpack and the prospect of an earlier spring runoff. University of Washington climate analyst Alan Hamlet compares this to "making summer several months longer than it is now." Many rivers, particularly the Columbia, are fed by snowmelt during summer. Reduced snowpack and earlier runoff means less-reliable water for hydropower, irrigation, and salmon runs.

"Streamflow is reduced at the time you need it most, in July and August," says Pacific Northwest National Lab climate scientist L. Ruby Leung. Salmon, in particular, face bleak prospects. Low water flows and a warmer atmosphere could heat streams beyond the salmons' endurance. On top of stresses already caused by dams, logging, and sprawl, global warming could be the "straw that breaks the salmon's back." Meanwhile, ocean warming could drive salmon out of the North Pacific.

Fisheries Canada research shows that once salmon enter the ocean, they rapidly head for waters not exceeding a certain temperature. By mid-century, unless global warming trajectories are moderated, salmon are unlikely to find those cool waters south of the Bering Sea. The swim back to Northwest spawning streams would become all the more challenging.

More Fire and More Rain
Global warming is projected to intensify regional swings toward drought and extreme rainfall. University of Washington climate researchers say climate models suggest a nine percent increase in winter precipitation and a five percent decrease in summer rains by around 2050. Under any scenario, more heat brings more evaporation, making for drier summer conditions.

Today, odds are the Northwest will face drought one year in 10. By 2020, a middle-of-the-road climate scenario shows odds doubling to once every five years. By 2050, the Northwest can expect a drought nearly one in every three years. If El Niņo becomes a nearly permanent condition (as climate models increasingly project), even these figures may understate the risk. Longer dry spells dramatically build forest fire dangers. Large fires come to the Central Washington Cascades about once every four hundred years. With global warming, these large fires can be expected every century. And after our suppressing natural fires for 100 years, many choked forests are just waiting for a spark.

At the other extreme, global warming could cause more "pineapple express" storms. Such inundations - which brought floods and killer mudslides to the Northwest in 1996-97 - were "an example of the type of weather patterns that would be expected to become more frequent ... as the climate continues to warm," National Climatic Data Center Chief Scientist Thomas Karl says. This represents a special concern for the Northwest - one the most slide-prone areas in the nation. Landslides are most likely during or shortly after downpours.

World sea levels have already risen 4 to10 inches over the past century. Another 3-inch rise is expected by 2020; 20 inches by 2100. Such rises would significantly boost storm surges, backing up rivers gorged with storm runoff and spreading floods far inland. Coastal communities such as Olympia, Raymond, and South Bend in Washington, and Tillamook, Cannon Beach, and Coos Bay in Oregon are particularly vulnerable.

We are vulnerable to circumstances far beyond our control. Yet, to save much of what we value, we must find a way to alter global trajectories. We can take the lead in offering global warming solutions by:

• Promoting climate-friendly solar, wind, and fuel-cell industries (areas in which the Northwest is already a world player)
• Fighting sprawl with smart community design, and
• Shifting to sustainable forestry and agriculture.

Knowing what is at stake, we can build a response to global warming that offers working models and useful products to help spur change around the world.

Patrick Mazza is senior writer-researcher for Climate Solutions [610 E. 4th Ave. Olympia WA 98501, (360) 352-1763, (fax) 943-4977] Climate Solutions, an Earth Island project, was created by a merger of EII's Atmosphere Alliance and the Energy Outreach Center. This column is based on a new report, "In Hot Water: A Snapshot of the Northwest's Changing Climate," available from Climate Solutions [www.climatesolutions.org].