"Climate change refers to a change in the state of the climate that can be identified (e.g. using statistical tests) by changes in the mean and/ or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use." (Intergovernmental Panel on Climate Change Control)

The Earth is kept habitable by gases in the atmosphere that capture part of the suns energy. Those gases are called "greenhouse gases" because of their heat trapping properties. At a relatively stable concentration, these gases are beneficial. Human activity has significantly increased greenhouse gases in the atmosphere since the beginning of the Industrial Revolution. Sources of greenhouse gas pollution from human activity have changed the global climate and will continue to change the climate for the foreseeable future. Our challenge is to slow, then reverse these global changes, so their near-term effects can be contained and the longer-term life-threatening impacts do not occur.

Image from Oregon Strategy for Greenhouse
Gas Reductions (Governor's Advisory Group
on Global Warming)

Now, and in the future, climate change may have important ramifications for Oregon's environment, economy and the health of Oregonians. In 2004, a Scientific Consensus Statement on the Impacts of Climate Change in the Pacific Northwest was developed. Impacts include:

Temperature. Scientists are medium certain that average temperatures in the Pacific Northwest will continue to increase in response to global climate change. Assessments suggest that the average warming will be 2.7 F by 2030 and 5.4 F. by 2050. These projected increases are highly likely to result in a higher elevation treeline, longer growing seasons, longer fire seasons, earlier animal and plant breeding, longer and more intense allergy season and changes in vegetation zones.

Precipitation. Precipitation changes are very uncertain. The challenge will be to resolve scientific uncertainties about the interactions among atmosphere, land and ocean before significant climate change impacts occur. Oregon is expected to remain a wintertimedominant precipitation regime (most precipitation in the winter with most precipitation in the mountains). Impacts on water resources due to low summer precipitation and earlier peak streamflow will likely include decreased summer water availability, changes in our ability to manage flood damage, shifts in hydropower production from summer to winter, and decreased water quality due to higher temperatures, increased salinity and pollutant concentration.

Sea Level. Sea level is very certain to continue to rise although the impact will vary depending upon how fast the land is rising. Maximum wave heights will likely increase, increasing erosion in coastal areas.

Snowpack. The April 1 snowpack will continue to decline corresponding to an earlier peak streamflow.

Marine Ecosystem. It is very certain that ocean circulation will continue to change in response to ocean-atmospheric processes. These changes suggest a likely increase in the length and magnitude of upwelling, which will affect marine ecosystems.

Terrestrial Ecosystems. The impact of changes in temperature and precipitation on terrestrial ecosystems is poorly known. Due to current biomass densities, the anticipated drier summers will increase drought stress and vulnerability of forests to insects, disease and fire.

Oregonians have been working to address the challenge of climate change. Governor Ted Kulongoski established the Governors Advisory Group on Global Warming in 2004 to advise him on climate mitigation strategies for Oregon. The Governors Climate Change Integration Group was established in 2006 to continue the work of the Advisory Group on Global Warming by focusing on adaption strategies. In addition, Oregon has participated in the West Coast Governors Global Warming Initiative, a regional effort to identify regional actions that West Coast states could take to reduce greenhouse gas emissions.

The Oregon Department of Energy has developed a Climate Portal, where extensive further information is available. The Oregon Climate Change Research Institute leads research on climate change in Oregon.

The U.S. Global Change Research Program released a 190-page report on Global Climate Change Impacts in the U.S. in 2009. The report includes a chapter on the regional climate change impacts in the Northwest.

Authored by Gail Achterman, Director, Institute for Natural Resources (2009)

Sources