By Sonia A. Hall

Fire danger was considered extreme on and around Labor Day 2020. Close to the Beachie Fire in Marion County, OR. Photo: Oregon Department of Transportation, under CC BY 2.0.

Most of us probably agree that 2020 was an unprecedented year in many ways. Much of the western U.S. will remember 2020 for, among other things, the extensive fires that burned across many states. One of those states is Oregon, where climatic and weather conditions converged during Labor Day to enable large fires across the western slopes of the Cascades. Check out climatologists John Abatzoglou, David Rupp, and Larry O’Neill’s article titled Climate Enabling Conditions and Drivers of the Western Oregon Wildfires of 2020. They discuss the conditions that enabled these fires, and provide some historical context for their occurrence. Spoiler alert: their concluding paragraph states that “The best science available indicates that the conditions that enable large wildfires and wildfire seasons will become more common as a result of climate change and past and current land management and land use.” Many communities are heeding this information and working towards reducing vulnerabilities and improving resilience, to better deal with future fires. Please share with us and AgClimate.net readers those tools, resources and information you have found useful in such efforts.  You can comment on this post, or contact us via the Ask A Question tab.

By Paris Edwards

Headwater streams originate in mountainous areas and add critical snowmelt to summer and early fall stream flows. Slow and steady melt off of winter snowpack provides water during the dry season when crops need it most. Photo by Picasa, Wikimedia Commons under CC BY-SA 3.0.

Our understanding of regional climate change effects today will be used to inform management, policy, and the new scientific endeavors of tomorrow. With this in mind, a team of doctoral students from the Water Resources Department at the University of Idaho in Moscow carried out a systematic review of all peer-reviewed studies through 2016 (550 of them) related to climate change in headwater regions of the Columbia River Basin. The purpose of the review was to explore what aspects of climate change impacts on water availability have been well studied, and where additional research is still needed (Marshall et al. 2020). We focused on mountain headwater regions because these critical water-generating areas are vulnerable to increasingly warm winter temperatures that contribute to snowpack losses and increased variability in the timing and volume of water available for multiple uses. Water availability supports values we care about and communities in our region, including irrigation; the future of irrigated agriculture in the Basin depends on water, and at least 20% of surface supply in the Basin is generated from melted snow. Continue reading →

By Patrick Shults, Washington State University Extension

Western redcedar with a dead top as a result of drought stress. Photo: Patrick Shults, WSU Extension.

The coastal Pacific Northwest is home to some of the best tree-growing conditions in the world.  Fertile soils, plenty of rain, mild temperatures, and short dry seasons allow trees to pack on solid growth each year.  These conditions also give them a significant advantage in protecting themselves from insects and disease with tactics like pitching sap to flush out bark beetles, isolating roots infected with fungus, and compartmentalizing wounds.  However, these defenses are only possible when trees can avoid environmental stressors and, given a changing climate, certain stressors are expected to become more frequent.

Trees in this area have evolved to handle an annual dry season and, generally, mild temperatures during that time ensure they don’t suffer too much stress.  However, in the last decade the coastal Pacific Northwest has experienced unusually stressful conditions.  The summers of 2015, 2017, and 2018, for instance, were very dry and also particularly hot, which worsens moisture stress in trees.  While it is difficult to attribute any given year to climate change, climate modeling suggests hotter summers like these may be a new normal, and a drive down I-5 in western Washington will show many trees have already paid a price. Continue reading →

By Mengqi Zhao, recent PhD graduate, Washington State University

Figure 1. Under low water availability conditions, the reliability of irrigation systems can be enhanced through strategies that improve water supply when it is needed or reduce water demand. Examples include greenhouses (left), aquifer recharge (recharge pond, top right), and irrigation technology (bottom right). Photos: Mengqi Zhao (greenhouse and pond) and Kay Ledbetter, Texas A&M AgriLife Research, under CC BY-NC-ND 2.0 (sprinkler).

For more than fifty years, individuals and organizations in the Yakima River Basin (YRB) have been working toward improving water availability, especially for agriculture. The mismatch between rainfall (and snowmelt) timing and the irrigation season has focused these efforts on strategies for increasing water storage. However, farmers frequently encounter insufficient irrigation water supply and large demands from agricultural activities, resulting in prorationing across irrigation districts during every severe drought of record since 1970s. In the Pacific Northwest, projected water scarcity situations under future climate change scenarios could increase to 68% of years in the 2080s if no actions are taken, compared to only 14% of years on average historically (Vano et al., 2010).

Facing such frequent low water availability conditions, what methods can improve the reliability of irrigation systems? How might people’s decisions on adopting those methods affect system vulnerability to droughts? The fundamental solutions to these questions rely on strategies that either improve water supply when it is needed or reduce water demand. Continue reading →