By Don MacGillivray


Climate change is here and it poses a growing threat to the nation’s citizens and resources. As carbon emissions increase, the atmosphere of the planet is heating up. Over the course of the past 2,000 years CO2 in the atmosphere has stayed roughly around 280 parts per million until the industrial revolution. In 1989 the 350 parts per million milestone was reached and recently the 400 parts per million was attained for the first time.

A panel of more than 300 climate scientists and experts analyzed the scientific research on climate  and achieved a consensus about the National Climate Assessment document recently released at the White House. As a result the United States plans to limit carbon pollution from existing power plants and set new goals for renewable energy sources like wind and solar. The national report provides a wake-up call to politicians and the energy industries to change their behavior for the good of the planet.

Portland’s future climate is expected to include warmer, wetter winters and hotter, drier summers with an increased frequency of high-heat days. In the Pacific Northwest temperatures have increased by 1.5 °F over the past century and it is likely to increase by 3° to 9° F by the end of this century.

The Portland / Multnomah County Climate Change Preparation Strategy identifies actions to prepare for the changing climate in two ways: 1) to reduce climate-related vulnerabilities, and 2) to respond to climate change impacts as they occur. Addressing the primary cause of climate change, carbon emissions, remains a crucial component of climate change preparation work. Unfortunately the magnitude of impacts of climate change depends largely on future global carbon emissions worldwide that is likely to continue regardless of humanities efforts to reduce it.

This Climate Change Preparation Strategy builds on existing work to understand how the climate affects the community today and in the future. The Climate Change Preparation Risk and Vulnerabilities Assessment report (a separate document)  provides an overview of the science and a more detailed review of the potential impacts to health and human systems, natural systems, infrastructure, and the built environment. In addition this strategy outlines priority actions in the areas of policy development, operations, planning, human services, as well as infrastructure and natural resource management.

The changes to the Natural Systems are likely to include: 1) lower summer stream flows, 2) increased risk of wildfire, 3) vegetation, habitat and wildlife shifts, 4) increased flooding and groundwater level rise, 5) increased erosion and potential for channel sedimentation, and 6) an increased risk of landslides.

The changes to the infrastructure and the built environment could be: 1) increased waste water temperatures causing water quality changes, wastewater treatment process impacts and increased odors, 2) pavement buckling, 3) increased water demand for irrigation, 4) stress on green infrastructure facilities, 5). increased chance of landslides impacting transportation and pipe infrastructure, and 6) an increase of the flooding of roads, sidewalks, bikeways, trails, and green infrastructure.

This is magnified by a phenomenon called the urban heat island effect. According to global climate models for the Pacific and Northwest region increasing temperatures and seasonal precipitation patterns are already evident. For example, reduced mountain snowpack and earlier springtime melting of snow are decreasing summer river and stream flows.

One example of the reports strategies are Portland’s long-established regulations and practices to protect, manage, and expand the City’s green spaces and urban forest. These efforts help to improve air quality and reduce the urban heat island effect, which in turn improves comfort and saves energy and money. Similarly, to protect public health the County currently monitors a variety of mosquito species that can carry vector-borne diseases such as West Nile Virus. These activities benefit the community and improve our resilience to natural hazards, regardless of future climate conditions.

In addition, this strategy considers potential climate change risks related to the built environment, food systems, energy systems, jobs and the economy. The strategy establishes twelve specific objectives for 2030 and identifies actions to build resilience into the City and County policies, operations, services, and infrastructure. City and County departments will integrate the actions into their work planning as new and existing resources are available.

This strategy is fundamentally linked to the City of Portland and Multnomah County 2009 Climate Action Plan, which integrates the City and County’s work to slow climate change while also preparing for the impacts that we will soon experience.