This is an archived article.

November 9, 1999

Climate change will have major Northwest impact in next 50 years

News and Information

Can Washington, Oregon and Idaho handle average temperatures more than 5 degrees warmer, 5 percent more annual precipitation, one-third less winter snowpack and a mountain snow line as much as 1,500 feet higher?


Climate models show such changes are possible in the three-state Columbia River Basin by the middle of the next century as a result of human causes, primarily the spewing of greenhouse gases such as carbon dioxide into the atmosphere, a broad panel of scientists and policy analysts said today. But most institutions charged with preparing for the future are ill prepared to respond effectively, the group warned.

The Climate Impacts Group at the University of Washington released the most comprehensive-ever examination of past and future climate change in the region. The report says that by 2050 the Northwest is likely to have warmer temperatures; wetter winters with more flooding and landslides; salmon struggling with lower streamflows and higher water temperatures in the summer and fall; and drier summers that make native trees more vulnerable to insects, fire and possible displacement by non-native species.

Some of the most serious problems detailed in the report relate to shrinking snowpack. Water supply systems are built with the expectation that a reliable “water bank” in the form of snowpack will provide adequate supply for the typically dry summer months. But winters just a few degrees warmer than usual, such as 1991-92, can mean drastically lower snowpack and summer water shortages. Climate scenarios for the future all project substantial warming by the 2020s, and summer water shortages could become common.

In the face of such shortages, the report outlines three main responses. One is to increase supply by steps such as developing new storage capability, reusing whenever possible and finding new sources. Another is to decrease demand through such steps as introducing a water market system that determines water prices and rights of use, developing technology to limit waste, reducing irrigation and cutting soil-moisture loss. The third is to increase flexibility by developing a regional water management database that could integrate federal, state and academic institutions so that all have the same information. Currently, no institution is capable of meeting all of those needs.

“Climate is not a constant, but people plan for the future as if it were,” said Philip Mote, a UW research scientist and lead author of the report. “Research about possible future climate change is useless unless institutions actually use the results to guide long-range planning.”

The report is part of the U.S. National Assessment of the Consequences of Climate Variability and Change and is the first regional report to be completed. The Northwest assessment was compiled by 19 scientists and policy analysts from the UW School of Marine Affairs, the Joint Institute for the Study of Atmosphere and Oceans at the UW, the Washington Department of Ecology, the Pacific Northwest National Laboratory in Richland, Wash.; the Battelle Memorial Institute in Seattle and the Portland (Ore.) Bureau of Water Works.

The scientists analyzed environmental changes in the past and projections from climate models to gauge the Northwest’s sensitivity to climate variations such as El Niño.

Because human activity is increasing the level of greenhouse gases in the atmosphere, some of the changes expected in the next 30 years would far exceed those observed in this century. In the last 100 years the region has gotten an average of 1.5 degrees warmer and 10 percent wetter, and computer models suggest those trends will continue. That will mean higher snow lines in the mountains, earlier spring thaw, lower summer water supplies, and increasing environmental stress for salmon and trees.

The report does not address whether the changes can be reversed, but rather advocates that institutions and government agencies be retooled to respond to scientific information and make sufficient plans to mitigate the effects of altered climate.

Three years ago the UW surveyed 30 public agencies in Idaho, Oregon and Washington that seemed most likely to use climate forecasts. Only two of them actually did so and most of the others hadn’t even considered trying, said Edward Miles, a UW marine affairs professor who heads the Climate Impacts Group. A federal study showed the same was true of the private sector.

Helping agencies, businesses and citizens understand and respond to climate variability and change became a key goal of the Climate Impacts Group, starting with the strong El Niño event of 1997-98.

“Awareness and responsiveness has increased each year, but more of our institutions must become aware of the effects of climate and climate variability on what they do,” Miles said.

For this effort, the group has received funding from the National Oceanographic and Atmospheric Administration’s Office of Global Programs and the UW Provost’s office.


Once planners and the public become aware of the impacts of year-to-year climate variations and long-term change, Miles said, they can make proper use of the forecasts and scenarios. Primarily that information will provide:


  • Short-term seasonal forecasts. These include expectations for conditions such as precipitation, streamflow and snowpack that affect specific sectors, such as agriculture or hydropower. “This would increase the efficiency of their use of the natural environment,” Miles said.
  • Longer-term decadal cycles. Planners would understand and prepare for the effects of a long drought or prolonged periods of flooding, brought about by changing phases of a climate phenomenon called the Pacific Decadal Oscillation in concert with El Niño and La Niña.
  • Decade- to centennial-scale scenarios. These look at probabilities of how climate might be altered on a century time scale by the continued emission of greenhouse gases.

Agencies and institutions need technical expertise to understand the forecasts, Miles said, and will have to work with groups such as his to understand probable impacts. Then they will need an organized internal response capability to mitigate effects of events such as drought or flooding.

In the federal government, he added, strong consideration is being given to organizing a national climate service within NOAA to provide the necessary links between climate forecasts and response planning.
But planning for climate change won’t be simple.

“When flooding threatens, the Army Corps of Engineers has clear authority to prevent it,” the report states. “But droughts are harder to prevent, and when droughts occur hundreds of entities, including states, irrigation districts, fisheries managers and tribes, all assert their rights to scarce water.”

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For more information, contact Mote at (206) 616-5346 or philip@atmos.washington.edu  Miles at (206) 685-1837, (206) 616-5348 or edmiles@u.washington.edu  or Nathan Mantua at (206) 616-5347 or mantua@atmos.washington.edu 
 


The following links provide additional information.




Executive summary of the regional report

(NOTE: The summary is in PDF format. Click here for a free download of Adobe’s Acrobat Reader.)