CORVALLIS, Ore. - Scientists with expertise in climate and its impacts have developed a "consensus statement" that summarizes the likely effects of climate change on the Pacific Northwest. They predict a future with higher temperatures, rising sea levels, diminished streamflows and snowpack, longer fire seasons and many other changes.

Climate change is real, is already under way, is being strongly influenced by human activities, and future effects may be even more dramatic, the report concludes. These changes could profoundly disrupt the Pacific Northwest environment, ecology, economy, agricultural base, forests and other entities.

The potentially catastrophic impacts of climate change also raise a myriad of questions that need to be addressed by further research, the report said, on topics ranging from wind patterns to precipitation changes, ocean dynamics and effects on human health.

The report will assist the work of the Advisory Group on Global Warming appointed by Oregon Gov. Ted Kulongoski. The advisory group just released a far-reaching set of recommendations on what Oregonians need to do to address climate change, available from the Oregon Department of Energy at Comments are being accepted until Nov. 15.

The findings in the consensus statement emerged from a meeting sponsored by the Institute for Natural Resources at OSU last June of 65 of the leading experts from the region, in oceanography, forest ecology, climate, marine ecology, fish biology, agriculture and resource economics, and other fields.

These experts were primarily academic scientists from Oregon State University, the University of Oregon, University of Washington, and Lewis and Clark College. The full report is available on the web at

Among the findings of the report:

  • Temperature: The Pacific Northwest has warmed from 1-3 degrees in the past century, mostly due to natural causes earlier in the 1900s and to human causes more recently. Scientists project with "intermediate certainty" that temperatures in the Pacific Northwest will further increase by 1-5 degrees by the 2020s and 3-6 degrees by the 2040s.


  • Effects of Warmer Climate: Higher temperatures will likely result in a higher elevation treeline, longer growing seasons, longer fire seasons, earlier animal and plant breeding, longer and more intense allergy seasons and changes in vegetation zones. Drier summers are anticipated, leading to greater drought stress and vulnerability of forests to insects, disease and fire.


  • Precipitation: Since the beginning of the 20th century, annual precipitation has increased across the Pacific Northwest by an average of 10 percent, and 30-40 percent in some areas of eastern Washington and northern Idaho. Future changes in precipitation are difficult to predict and very uncertain.


  • Sea Level: Land on the central and northern coast of Oregon, from Florence to Astoria, is being submerged by rising sea level at a rate of 1.5-2 millimeters per year, and globally has risen by 4-8 inches in the past century. It's certain that the sea level will continue to rise, although in the Pacific Northwest the impact will also depend on how fast the land is rising due to tectonic uplift. A global sea level rise of from four inches to almost three feet by 2100 is possible. Maximum wave heights will likely increase, leading to heavier coastal erosion.


  • Snowpack: Snowpacks across the West have been diminishing for 50 years, caused almost equally by warmer temperatures and decreased precipitation during the winter season. It's highly certain that spring snowpack in the Pacific Northwest will continue to decline in many areas, resulting in further losses of natural water storage in the mountains. Mid-level elevations will suffer the greatest snowpack losses.


  • Marine Ecosystems: The magnitude and duration of upwelling will likely increase, but it's unclear whether this may lead to increased primary ocean productivity or more "dead zone" events such as those that have occurred twice in the last three years.


  • Water Demand: Little precipitation in summer, warmer temperatures, an earlier drop in streamflows, and greater water demand based on population growth should lead to intensified conflicts over scarce water resources. Intensified streamflows in the winter and spring will likely lead to increased flooding events during those seasons, while diminished streamflows in the summer will likely result in increased summer droughts.


  • Water Quality: Higher temperatures in lakes and streams, increased salinity, pollutant concentration and lower levels of dissolved oxygen could provide increased stresses on fish health.

The scientists emphasized that although they are able to make predictions about some likely changes, there are also still many uncertainties. Precipitation is a big unknown. Some models, for instance, predict a modest increase in winter precipitation and decreases in the summer. But large-scale changes in ocean temperature and circulation patterns could yield a Northwest climate that is drier.

It's also unclear exactly how marine and terrestrial ecosystems will respond to these changes, and what human land management changes may take place as it becomes clear that the climate is changing.

Some of the most pressing needs for future research, the study indicated, are in the area of precipitation patterns, coastal ocean winds and associated upwelling, the thresholds for abrupt shifts in climate, and the dynamics of large, long-term changes in ocean and atmosphere interactions.

On a global basis outside the Pacific Northwest, the report made note of many other climatic changes that are underway or anticipated as a result of global warming - shorter duration of ice cover on lakes and rivers, thinner Arctic sea ice, retreat of glaciers, loss of permafrost, longer growing seasons, shifts in plant and animal ranges, bleaching of coral reefs, increase in severe weather events, and other changes.

Click photos to see a full-size version. Right click and save image to download.


Sherm Bloomer, 541-737-4811