The Pacific Northwest Climate CIGnal
The Climate Impacts Group (CIG) issues a quarterly electronic newsletter designed to provide updates on regional climate and climate-related research, meetings, and topics of interest to Pacific Northwest (PNW) decision makers and resource managers. The first newsletter was distributed in January 2005.
To subscribe to the newsletter, please visit the CIG's "climateupdate" listserve home page. You can also subscribe to the newsletter by sending a blank email to the following address: firstname.lastname@example.org.
The Pacific Northwest Climate CIGnal
Issue #9, Winter 2007
In this Issue
- Pacific Northwest climate outlook
- Pacific Northwest streamflow forecast updates
- New global climate change scenarios released
- New report on the economic impacts of climate change in Washington State
- Discussions on recent Pacific Northwest snowpack trends
- NCDC recap of global, U.S., and regional 2006 climate
- King County Climate Plan released
- Working on adaptation?
- Office of the Washington State Climatologist newsletter and listserve
- CIG in the news: Recent media stories
1. Pacific Northwest climate outlook
The wet, windy, and icy conditions in November, December, and early January finally gave way to more seasonable weather in mid-January. When January and February are averaged together, temperatures were close to or somewhat below the long-term average around the Northwest. Precipitation has been below to much below average at most locations in the PNW. What happened to El Niño? What is the forecast for the coming months? Read more about the Pacific Northwest outlook...
2. Pacific Northwest streamflow forecast updates
West-wide Seasonal Hydrologic Forecasts Update (Columbia R., Snake R., and other western-U.S. rivers)
An unusually wet November and December gave way to relatively drier and colder conditions from late December to mid-February, resulting in near normal soil moisture levels throughout the Pacific Northwest. Snowpack in Washington 's Cascade Range is above normal, but below-average snowpack in the Columbia River basin as a whole has produced declines in streamflow forecasts from 104% in early December to 92% of average flow in early February for the Columbia River at The Dalles, Oregon. Snowpack in the Snake River basin is below normal and the streamflow forecast for the Snake River at Clarkston, Washington has been reduced from 101% of average early in the season to 78%.
Graphical depictions of recent estimates of soil moisture, snow water equivalent, and streamflow can be found at the University of Washington's West-wide Seasonal Hydrologic Forecast System website. These experimental real-time forecasts are updated monthly and are based on several climate forecast methods. A number of products at the web-site, however, are now updated on a daily basis. These include basin-averaged water balance conditions for each forecast point, spatial maps of current conditions, and a spatial summary of snow water equivalent for the western U.S.
A related effort, showing daily updates of hydrologic conditions throughout the U.S., can be found on the UW Experimental Surface Water Monitor website. The Surface Water Monitor shows daily updating estimates of hydrologic conditions throughout the U.S. New daily data products include water balance estimates for the Missouri, the upper Rio Grande, and the Arkansas-Red River Basins. Since the website's launch in April 2005, the Surface Water Monitor has increasingly become a data source used by U.S. Drought Monitor and Drought Outlook authors in the preparation of their operational products.
3. New global climate change scenarios released
A summary of the latest report on global climate change from the Intergovernmental Panel on Climate Change (IPCC) was released on February 3, 2007. The IPCC reports, released about every five years, provide the most comprehensive assessment of global climate change science, trends, and impacts in the world. Climate Change 2007: The Physical Science Basis, Summary for Policymakers summarizes progress in “understanding of the human and natural drivers of climate change, observed climate change, climate processes and attribution, and estimates of projected future change”. Among the major findings reported in the Summary for Policy Makers were the following:
- Global atmospheric concentrations of carbon dioxide, methane, and nitrous oxide are currently 35%, 147%, and 18% higher, respectively, than pre-Industrial (1750) levels. Present-day concentrations of carbon dioxide and methane far exceed the natural range of these gases in the last 650,000 years.
- Global average annual temperature increased 1.3°F (0.74°C) between 1906 and 2005. Eleven of the last 12 years (1995-2005) rank among the 12 warmest years for average global temperature since 1850.
- It is very likely (greater than 90% chance) that most of the warming since the mid-20th century is due to human-caused increases in greenhouse gas concentrations.
- Global temperatures are projected to increase 3.2°F to 7.2°F (1.8°C to 4.0°C) by the decade of the 2090s relative to average temperature for 1980-1999. This is the “best estimate” range.
- Global sea level rise is projected to increase 7-23 inches (0.18-0.59 meters) relative to average sea level for 1980-1999.
The full report from Working Group 1 on the scientific basis for climate change will be released in May 2007. Subsequent reports from Working Group 2 (impacts, adaptation, and vulnerability) and Working Group 3 (mitigation) will be available in April and May 2007.
4. New report on the economic impacts of climate change in Washington State
The Washington State departments of Ecology and Community, Trade & Economic Development released a report on the economic impacts of climate change on Washington State on January 10, 2007. Impacts of Climate Change on Washington's Economy: A Preliminary Assessment of Risks and Opportunities examines seven key sectors, industries, and regions of Washington State and uses existing research from the Climate Impacts Group and others for this first-ever assessment of potential economic impacts to Washington. The report's authors reached three broad conclusions about the effects of climate change on Washington’s economy:
- Climate change impacts are visible in Washington State and their economic
effects are becoming apparent.
- The economic effects of climate change in Washington will grow over time
as temperatures and sea levels rise.
- Although climate change will mean increasing economic effects, it also opens the door to new economic opportunities.
Findings specific to water resources, forest ecosystems, and other aspects of Washington's economy are available in the report. The report was prepared by faculty and staff from the Climate Leadership Initiative at the University of Oregon's Institute for a Sustainable Environment. A similar report on the economic impacts of climate change in Oregon was prepared by the Institute in 2005.
5. Discussions on recent Pacific Northwest snowpack trends
On February 24, 2007, The Oregonian reported on a debate between researchers at the University of Washington on recent trends in 20th century snowpack in the Washington Cascades. The issue originated with the publication of an op-ed written by the Mayor of Seattle on February 7 stating that “The average snowpack in the Cascades has declined 50 percent since 1950…”. In question was the 50% statistic for the Cascades and the implication that the reported decline was due entirely to anthropogenic (human-caused) climate change; the 50% figure had appeared, erroneously, in the June 2004 report "Scientific Consensus Statement on the Likely Impacts of Climate Change on the Pacific Northwest" (Oregon State University). Mark Albright, of UW Atmospheric Sciences, noted that at the most complete snow courses (a small subset of the total) for the Cascades, the last 10 years were only a little below the long-term average.
To help resolve questions over the statement, a group of University of Washington climate and weather scientists met to review the different statistical approaches used to examine trends in spring snowpack, also referred to as snow water equivalent or SWE. Professor Dennis Hartmann, the Chairman of the Department of Atmospheric Sciences, was asked to prepare a summary statement on the issue. The statement reiterated many of the CIG's research findings on trends in SWE and added additional important insights into recent trends. In summary:
- 20th century snowpack trends. CIG research shows that Pacific Northwest SWE has declined since monitoring became widespread in the late 1940s, with 30-60% losses at many *individual* monitoring sites in the Cascades (Mote 2003, Mote et al. 2005). When looking at the period 1950-1997, the overall observed decline in April 1 SWE for the Cascades is -29% (Mote et al. 2005). Relative losses are greatest in lower and mid-elevations where mid-winter temperatures are warmer; higher elevation sites where average mid-winter temperatures are still well below freezing (even with 20th century warming) don't show any declines in SWE.
An examination of SWE trends for more recent years (e.g., beginning about 1975 or later) appears to show a small increase in SWE for the Cascades, consistent with Albright's finding about the average of the last 10 years, though SWE in the last five to seven years has been at least 20% below the long-term mean. This leveling of the trend appears to be associated with increased precipitation in the late 1990s, especially the near-record wet winter of 1998-99, and appears to have temporarily offset the persistent declines produced at low elevations by warming. Trends over intervals as short as 30 years are rarely significant, given the shorter time frame and the higher precipitation and snowpack variability experienced in the PNW since the mid-1970s. In other words, the apparent leveling of trends appears to be the result of large natural variability in precipitation masking the declines driven by temperature.
- Data availability. Data availability is a limiting factor in long-term SWE trends analysis. Prior to the mid-1940s, there were very few snowpack monitoring sites with continuous data sets and those that had continuous data sets tended to be located at high altitudes known to be less sensitive to warming trends. These factors make it difficult to assess SWE trends before the 1940s with high statistical certainty, and results are not consistent with more complete analyses for later periods because of the high elevation bias in the available data. By mid-century, the availability of data and distribution of snowpack monitoring stations is much improved, allowing for a more robust analysis of SWE trends. “A substantial collection of snow course data records with a reasonably representative and stable distribution with altitude exists since about 1945,” notes Prof. Hartmann.
- The role of natural variability. Natural variability has played - and will continue to play - an important role in determining year-to-year and decade-to-decade variability in SWE. Mote 2006 found that natural variability as represented by the North Pacific Index (NPI) explains about 50% of the trends in Pacific Northwest SWE since mid-century (and less from earlier starting points). The remaining portion of the trend “clearly includes the influence of the monotonic warming observed throughout the West, which is largely unrelated to Pacific climate variability and may well represent human influence on climate” (p.6219). Natural variability has also played a role in 20th century Pacific Northwest temperature trends, explaining perhaps one-third of November-March warming in the region since 1920 (Mote et al. 2005, p.47).
As noted above, natural variability will continue to be a factor in 21st century snowpack accumulation. The Pacific Northwest will have good snowpack years in the coming decades as well as poor snowpack years even as the long-term temperature trends continue. This natural variability can hide long-term trends over short periods of time. Additionally, the potential for increases in precipitation as a result of climate change may make it difficult to see distinct trends in the near-term.
- Future impacts. The warming projected for the 21st century is expected to have a significant negative impact on snowpack, particularly mid-elevation snowpack, even if increased precipitation from natural variability and/or climate change is enough to "hold off" the impacts of warmer temperatures on snowpack in the near term. Changes in 21st century precipitation are less certain than temperature, however. Given that approximately 50% of the snowpack in the Cascades sits below 4200 feet, where spring snowpack is very sensitive to small increases in average temperature, preparing for climate change impacts is critical.
For more information on Pacific Northwest snowpack trends, please contact Philip Mote at the Climate Impacts Group.
6. NCDC recap of global, U.S., and regional 2006 climate
Scientists at NOAA's National Climate Data Center (NCDC) reported on January 11, 2007, that 2006 was the 5th warmest year on record for global average temperature, although uncertainties in the global calculations (due largely to gaps in data coverage) make 2006 statistically indistinguishable from 2005 and several other recent warm years. Global average annual temperature for 2006 was +0.97°F (+0.54°C) above average. A statement from the World Meteorological Organization on the 2006 ranking is expected later this month. For more on the NCDC's global summary, please see the NCDC's Climate of 2006 - Annual Report.
For the contiguous Unites States, NCDC found that 2006 was the warmest year on record. Based on preliminary data, 2006 annual average temperature was 2.2°F (1.2°C) above the 20th century mean of 55°F and 0.07°F (0.04°C) warmer than 1998, now the second warmest year on record according to current NCDC data. It is important to note that beta testing of an improved data set scheduled to be released in 2007 shows slight differences in average annual temperatures that can affect how individual years are ranked. In this case, the new data set shows that 1998 is still the warmest year on record by 0.05°F.
Average annual temperature in the Pacific Northwest was above to much above normal for 2006. Average annual temperatures in Washington, Oregon, and Idaho were the 97th, 101st, and 102nd warmest years, respectively, in 112 years of record (see temperature map). Annual precipitation was also above normal for the region, ranking as the 89th (Idaho), 95th (Oregon), and 100th (Washington) wettest years in 112 years of record (see precipitation map).
For more information on these findings and the comparative ranking of the top 25 warmest years on record in the continuous U.S., please see the NCDC's 2006 Annual Climate Review: U.S. Summary.
A month-by-month recap of 2006 Washington State climate is available in the January 2007 newsletter from the Office of the Washington State Climatologist.
King County, Washington, released its first climate change plan on February 7, 2007. The plan, created by a multi-disciplinary team of county staff, describes the County's plans for reducing carbon dioxide emissions and adapting to the impacts of climate change. Among the adaptation activities to be implemented under the plan are the following:
- Review all plans, policies, and investments in light of climate change impacts to determine where climate change impacts may affect County operations;
- Create a Flood Control Zone District and get funding for needed improvements to levees and other flood control structures in anticipation of increased flood risk;
- Evaluated and plan for potential impacts of flooding associated with sea level rise;
- Identify, preserve, and protect significant historical and archaeological properties vulnerable to climate change impacts;
- Incorporate climate change impacts information into construction, operations and maintenance of infrastructure projects;
- Develop a workgroup within the Department of Natural Resources and Parks to address climate change impacts to instream flows;
- Identify and pursue research that will improve understanding about climate change impacts to the region; and
- Conduct outreach and education to raise awareness and engage partner governments, agencies, organizations, and residents in planning for climate change.
More information on King County's climate change activities is available at the King County climate change web page.
Is your community, agency, or department developing approaches for adapting to the impacts of climate change? If so, please contact Lara Whitely Binder. Over the coming year, the CIG will be collecting information on adaptation efforts to include in an expanded series of web pages on adapting to climate change.
9. Office of the Washington State Climatologist newsletter and listserve
The Office of the Washington State Climatologist now offers a monthly newsletter containing information on the current state of Washington 's climate, including the current outlook and a review of notable climate and weather events. The newsletter is produced monthly and is available on the OWSC website or by e-mail subscription.
To receive the newsletter by e-mail, visit the Climate_newsletter subscription page or send a blank e-mail to: email@example.com.
10. CIG in the news: Recent media stories
Recent media stories featuring CIG research and/or researchers include the following:
- Warming trend affects water - KIFI ABC affiliate in Eastern Idaho, February 28, 2007
- Global Warming - Clark County in the cross hairs - The Columbian, February 25, 2007
- What is the state of Northwest snowpack? - The Oregonian, February 24, 2007 (read related statement from the UW Department of Atmospheric Sciences on the snowpack discussions featured in The Oregonian story)
- The coming storm - The Mail Tribune, February 11, 2007
- State should find ways to protect City Light's climate-protection efforts - The Seattle Times, February 7, 2007
- UW researcher in spotlight on global-warming issue - The Seattle Times, February 2, 2007
- Experts square off on climate change - The Oregonian, January 29, 2007
- Capitol Dispatch: For climate change talk, not much good news - The Daily News, January 25, 2007
- Northwest forecast: Dramatic change - The Oregonian, December 31, 2006
Additional news items are available at CIG in the News.
Posted March 3, 2007