Final Blog: Climate Change in Portland Oregon
Our world is facing a great challenge, one that is arising due to an increase in global temperatures. Temperature change will have many effects, including changes in precipitation, sea level rise, increased desertification, increased extreme weather events and changes in weather patterns. All areas of the world will be effected with varying degrees of change, some more extreme than others. Portland, Oregon is no exception to this, and will be dramatically affected by climate change due to geographic, demographic, economic, and other factors.
The Intergovernmental Panel on Climate Change (IPCC) published the document Climate Change 2007: Synthesis Report Summary for Policy Makers. The report documents and discusses climate changes in chapters titled Observed Changes in Climate and Their Effects, Causes of Change, Projected Climate Change and its Impacts, Adaption and Mitigation Options, the Long Term Perspective. This document looks at regional observed change, and future predictions and impacts on those regions. It also discusses the same for types of climates located world-wide.
Oregon has different climates due to many geographic and topographic features discussed in prior blogs. This includes influences from the nearby Pacific Ocean, the presence of two mountain ranges, and varying air masses that impact weather. The entirety of Oregon's weather has been and will continue to be impacted by climate change. Portland, Oregon has already felt the effects of climate change, reflected through rising temperatures and decreased precipitation when measured over the last century. Globally, the 100 year linear trend from 1906-2005 was an increase of 0.74 degrees Celsius. Oregon's temperatures average a 0.8 degrees Celsius increase, although this varies locationally throughout the state, with some regions reflecting a cooling trend. Portland's temperature trends are rising, and warming trends are reflecting greater temperature increases in the winter months, and weaker increases in fall months. Additionally, greater temperature rise in seen in the trending of Minimum temperatures.
The following maps reflect the Maximum and Minimum temperature trends in Oregon
Maps: http://depts.washington.edu/landecol/PDFS/OR-CC-report.pdf
These maps show the variability occurring throughout the state of Oregon with respect to Maximum and Minimum temperatures. Portland is not experiencing the highest gains for Maximum Temperature trends, however it appears to be near the highest coefficients for Minimum Temperature trends in the state.
Precipitation is another component of weather that is being impacted by climate change. Long term precipitation trends show less change than that of temperatures. Additionally, these long term trends are impacted by a wet period that occurred at the start of the twentieth century. Shorter term precipitation trends reflect greater change, with differing effects throughout the state of Oregon. Portland has become dryer, while other areas of the state are receiving greater amounts of precipitation, but again, at a less dramatic rate of change than temperatures.
The following maps reflect precipitation trends in Oregon
Maps: http://depts.washington.edu/landecol/PDFS/OR-CC-report.pdf
These maps reflect the greater precipitation variability that has occurred during more recent years in Oregon due climate change, magnified by geographic and topographic differences throughout the state impacting weather. The combined effects discussed reveal the Portland area undergoing a general warming and drying trend.
Portland should expect these trends to continue. The models that the IPCC uses show a potential increase of temperatures in the Pacific Northwest in 2040 ranging from 0.8 to 2.6 degrees Celsius, and an increase between 1.6 and 4.9 degrees Celsius by 2080. Precipitation models used by the IPCC predict that generally in the Pacific Northwest there will be increased precipitation in the winter months and decreased precipitation in the summer months. There is great variability locally, and exact estimates of change for the Portland area are not given.
Given the potential for increased precipitation in the winter months, there will be greater risk for winter flooding in Portland. This is magnified by Portland's close proximity to both the Columbia River and the Willamette River and its many areas that are low-lying near these rivers. During the summer months, there will be a larger risk of drought than the area is accustomed to.
The effects of temperature rise and precipitation change will affect the Portland region in many ways. One of the most important factors to consider when anticipating climate change is the hydrological cycle. Warmer temperatures will result in more winter precipitation falling as rain, altering snowpack and traditional melting patterns, potentially affecting water supplies, hydroelectric power creation, navigation, recreation, and ecosystems tied to rivers and streams. Portland supplies its water needs with two dams, designed with minimal capacity intended to refill annually. This could become problematic during cycles of prolonged drought. Spring run-off occurring at earlier times in the year could prematurely fill the reservoirs, resulting in shortfalls during the dryer summer months. Additional stress could be placed on water storage supplies from increased evapotranspiration due to higher temperatures and a dryer climate. A Portland Water Bureau publication estimates that water shortfalls directly attributed to climate change approach 1.5 billion gallons as soon as 2020.
Another potential event that may increase in the future due to climate change effects in the Portland region is fire. The area outside of the city itself contains many forests which are susceptible to burning due to increased aridity and temperatures. This could directly impact the economy of lumber and associated industries. This risk highlights the potential effects of change on the greater ecosystem of the Portland area. Plants, animals and the systems they have adapted to will require further adaption, or they will suffer as a result of climate change. Changes to freshwater supplies from raising temperatures will affect fish and fisheries, wildlife in the city and surrounding areas, as well as crops and other plantings.
Sea level rise is another risk associated with climate change. Portland should not be directly impacted by sea level rise during the remainder of this century. It lies approximately 20 feet above sea level at the Columbia River's edge. The IPCC's highest estimates for sea level rise, not including impact from melting ice sheets, is .59 meters, far below an elevation that would directly affect Portland. Impacts of sea level rise could affect the Columbia River itself, increasing salinization further inland, affecting surrounding ecosystems. What is less understood, potentially affecting Portland on a a greater scale, is sea level rise associated with the melting of ice sheets and caps. This is estimated to occur on a millennia time scale, but the effects on Portland would be catastrophic if the anticipated rise of 7 meters or 21 feet occurs.
Portland is relatively progressive when anticipating and combatting climate change. In 1993, they were the first city in the US to enact a local plan addressing greenhouse gas emissions, including land use planning, transportation, energy efficiency, solid waste and recycling, urban forestry, and renewable energy. As a result of this, and other actions and policies, Portland's carbon emissions have dropped 26% per person since 1990. In 2009, they adopted a Climate Action Plan, with the goals of achieving a 40% reduction by 2030, and an 80% reduction by 2050. Despite these aggressive measures, they will still be effected by climate change induced from beyond their borders. Climate is not a locally isolated phenomena, and because most other areas in the world have not been progressive on addressing greenhouse gas emissions, Portland will be affected.
Due to their understanding of this, action plans and policies are being put in place to counteract the occurring and anticipated effects of climate change. In 2010, Portland updated their Natural Hazard Mitigation Plan which contains plans for protecting populations and anticipating disasters from earthquakes and volcanos (independent of climate change) as well as severe weather, flooding, landslides, erosion, wildland urban interface fire, and invasive plant species, all of which could be exacerbated from effects of climate change. Additionally, many of Portland's residents, businesses, and systems have adopted the Climate Action Plan steps, lending a greater regional understanding to the threat climate change has on Portland, its environs, the US, and the world.
Water supplies should be expanded to accommodate the increased need anticipated, as well as flexibility built into the system. Conservation should be pushed further. The Pacific Northwest is generally perceived as a wet climate, masking the real need for adaptation and mitigation with respect to climate change with their water resources. Additionally, the area is heavily dependent on hydro-electric power, and the system should be evaluated and modified if necessary in anticipation of future hydrologic changes. Portland should also expect to receive climate refugees from its nearby coastlines if sea level rise is more dramatic during this century than expected. If catastrophic sea level rise occurs, plans should be enacted to offset the rise by relocating parts of the city expected to be inundated, or more prone to flooding, or potentially relocating the entire city to higher elevations.
Climate change is real, and we are seeing results today, and can expect to have greater changes in the future. Portland can offset many of the anticipated effects through planning, funding and a heightened awareness of the issue, and they are admirable in the steps taken to mitigate carbon emissions, however it won't be enough to stop change from affecting the city.
Works Cited:
Portland Office of Emergency Management. Portland Natural Hazard Mitigation Plan 2010, Executive Summary. Portland, Oregon. 2010. retrieved May 8, 2012 from: http://www.portlandonline.com/oem/index.cfm?a=329440&c=53813
Intergovernmental Panel on Climate Change. Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaption, Summary for Policymakers. IPCC. 2012. retrieved May 8, 2012 from: http://www.ipcc-wg2.gov/SREX/images/uploads/SREX-SPMbrochure_FINAL.pdf
Intergovernmental Panel on Climate Change. Climate Change 2007, Synthesis Report, Summary for Policymakers. IPCC. 2007. retrieved May 8, 2012 from: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf
Lawler J. J., M. Mathias, A. E. Yahnke, and E. H. Girvetz. Oregon’s Biodiversity in a Changing Climate. 2008. Report prepared for the Climate Leadership Initiative, University of Oregon. Retrieved May 8, 2012 from: http://depts.washington.edu/landecol/PDFS/OR-CC-report.pdf
Palmer, R. and Hahn, M. An Investigation of Potential Hydrologic and Management Impacts on the Bull Run System. Report prepared for Portland Water Bureau, January 2002. Retrieved May 8, 2012 from: http://cses.washington.edu/db/pdf/palmerhahnportland111.pdf
