Fourth Oregon Climate Assessment Report

“Oregon is already experiencing statewide impacts of a changing climate.” Thus begins the Fourth Oregon Climate Assessment Report released in January of this year.

Just take a look at some of the impacts experienced by Oregonians that the report covers:

  • “In August 2018, Portland and the Willamette Valley experienced some of the worst air quality on the planet owing to smoke from wildfires near and far.” (By the way, wildfires are expected to become more frequent under climate change.)
  • “Ranchers in southern and eastern Oregon reported significant economic losses caused by lack of water from a low winter snowpack and a hot and dry summer.”(Such conditions are also expected to become more common under climate change.)
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Mote, Philip W., John Abatzoglou, Kathie D. Dello, Katherine Hegewisch, and David E. Rupp. “Fourth Oregon Climate Assessment Report, Oregon Climate Change Research Institute.” Corvallis, Oregon: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 2019. http://www.occri.net/ocar4.

However, the report notes, while climate change has touched all corners of Oregon, some communities are more vulnerable than others. These frontline communities are experiencing the first, and often the worst, effects of climate change impacts. Frontline communities include the economically disadvantaged and those who depend on natural resources for their livelihood, among them rural residents, including Native Americans.

Fourth Oregon Climate Assessment Report comes from the Oregon Climate Change Research Institute (OCCRI). Its authors include OCCRI and CIRC’s Philip Mote, Kathie Dello, and David Rupp at the Oregon State University and CIRC’s John Abatzoglou and Katherine Hegewisch at the University of Idaho.

Consisting of two chapters, the report represents a convergence of evidence of the risks that Oregon is facing and will continue to face under a changing climate. Chapter 1 summarizes the current state of knowledge of the physical changes in climate and hydrology, focusing on what has been learned since the previous Oregon Climate Assessment Report. The report’s second chapter covers impacts, reprinting verbatim, the Northwest chapter of the Fourth National Climate Assessment (NCA4), which was released by the federal government in November 2018.

Other key findings of the report include:

“Oregon continues to warm in all seasons, in part due to human activity.”

“Warming is projected to continue in all seasons, dependent on global activity.”

“Hot days will become more frequent in Oregon in a changing climate.”

“Changes in rainfall will accentuate extremes.”

“Sea level rise projections have not change substantially through mid-21st century, though estimates of the maximum plausible sea level by the end of the century (2100) have increased to 8.2 feet.”

“Nearly every location in Oregon has seen a decline in spring snowpack, and it will continue to significantly decline through mid-21st century, especially at lower elevations.”

“Fire activity is strongly linked to summer climate, with the largest fires occurring exclusively in warm and dry summers.”

“Climate change may also present a potentially opportunity for agriculture with a longer growing season, though producers may be limited by water availability and limited adaptive capacity.”

“The challenges are great, but there are opportunities to adapt to a rapidly changing Oregon.”

CIRC’s Northwest Climate Toolbox features prominently in the report. Data, figures, and maps were taken directly from the Toolbox to communicate the latest climate projections for several variables, including the frequency of hot days, growing season length, snow water equivalent, soil moisture, streamflow, and fire danger.

OCCRI produces a climate assessment report for Oregon lawmakers every couple of years as required by state law.

A PDF of the report can be downloaded at www.occri.net/ocar4. A web version of the report is coming soon. We’ll keep you posted.


OSU_icon_gears_Black Resources: 


OSU_icon_pencil_Black RotatedPublication: Mote, Philip W., John Abatzoglou, Kathie D. Dello, Katherine Hegewisch, and David E. Rupp. “Fourth Oregon Climate Assessment Report, Oregon Climate Change Research Institute.” Corvallis, Oregon: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 2019. http://www.occri.net/ocar4.


Meghan Dalton is a lead author of the Tribal Climate Adaptation Guidebook and the Third Oregon Climate Assessment Report as well as a co-author on the Northwest chapter of the Fourth National Climate Assessment. Her other publications include the extended report Climate Change in the Northwest: Implications for Our Landscapes, Waters, and Communities. A climate researcher with a BA in Mathematics and a MS in Atmospheric Science, Meghan has worked on Community Adaptation projects with several Pacific Northwest communities, including the water provider Seattle Public Utilities for the PUMA project.


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