Greg Pederson, Ph.D.
Biography
Education
Ph.D. Watershed Management & Ecohydrology. 2010. University of Arizona, School of Natural Resources.
M.S. Environmental Science. 2004. Montana State University
B.S. Ecology and Evolution in Botany & Zoology. 2000. Michigan State University
Research Interests
Greg Pederson is a research scientist working primarily on the role of climate variability in driving changes in water resources, and other biological and physical components of mountainous ecosystems in western North America. Of particular interest is the magnitude of low-frequency hydroclimatic variability and its implications for drought risk, as well as the climatic drivers associated with observed changes in mountain snowpack, streamflow, glaciers, and forest disturbance events. Understanding the time intervals and spatial scales over which these processes operate requires a long-term perspective, and for that I rely on proxy records primarily from tree-ring and lake sediments along with instrumental and modeled climate records. Recent and ongoing studies have addressed the susceptibility of natural resources to climate variability and change, and sought to apply both the modern and paleoclimatic records to present day resource management problems. Greg is affiliate faculty with the Earth Sciences department and the Institute on Ecosystems (IoE) at Montana State University. He grew up in Michigan and earned his B.S. in Ecology and Botany from Michigan State University, before moving to Montana to earn a M.S. from Montana State University. In 2010 he completed his Ph.D in watershed management and ecohydrology at the University of Arizona then returned to Bozeman Montana.
Current Research Projects Include:
- Drivers of Drought in the Upper Colorado River Basin [DOI Southwestern CSC]
- Multi-century perspectives on current and future streamflow in the Missouri River Basin [NSF P2C2]
- Reconstructions of Columbia River flow from winter and summer precipitation sensitive proxies in the Northwestern U.S. with implications for 21st century flow [CSC and CLU]
- A Broader view of North American climate over the past two millennia: Synthesizing paleoclimate records from diverse archives [USGS Powell Center]
- Holocene climate variability in Alaska from relict wood [DOI Alaska CSC]
- Holocene climates of the Northern Rockies from relict wood emerging from ice patches [CLU]
- Megadroughts and uncertainty in Upper Colorado River flow low-frequency variability [CLU]
Science and Products
Reconstructing Ancient Human and Ecosystem Responses to Holocene Climate Conditions
This research project will reconstruct Holocene climatic conditions to better understand human adaptation and response to past environmental variability.
Multi-century perspectives on current and future streamflow in the Missouri River Basin
The Missouri River system is the life-blood of the American Midwest providing water resources that drive agriculture, industry, hydroelectric power generation, and ecosystems. However, the Missouri River Basin (MRB) (Figure 1) is the only major river in the western U.S. for which hydrologic reconstructions from tree rings have not been generated in any systematic way. This knowledge gap is...
Drivers of Drought in the Upper Colorado River Basin
The purpose of this project is to investigate Colorado River basin droughts, and the role of temperature in influencing runoff efficiency. The project uses paleoclimatic data to extend instrumental climate and flow records, along with projected warming to assess the range of possible conditions that may be expected to occur and to determine how warming temperatures may influence river flow and...
Greg Pederson's Past Projects
This work is interdisciplinary and would not be possible without the collaboration of colleagues and their respective institutions. Research funding over the years has been provided by 1) the U.S. Geological Survey's National Research Program (NRP), the Climate and Land Use Program (CLU), the Southwestern and Alaska Climate Science Center, the Western Mountain Initiative (WMI), and the...
Broader view of North American climate over the past two millennia: Synthesizing paleoclimate records from diverse archives
Regional- to continental-scale paleoclimate syntheses of temperature and hydroclimate in North America are essential for understanding long-term spatiotemporal variability in climate, and for properly assessing risk on decadal and longer timescales. However, existing syntheses rely almost exclusively on tree-ring records, which are known to underestimate low-frequency variability and rarely...
Science and Forecasting to Inform Implementation of the Greater Yellowstone Coordinating Committee’s Whitebark Pine Management Strategy
The goal of this project was to inform implementation of the Greater Yellowstone Coordinating Committee (GYCC) Whitebark Pine (WBP) subcommittee’s “WBP Strategy” based on climate science and ecological forecasting. Project objectives were to: 1. Forecast ecosystem processes and WBP habitat suitability across the Greater Yellowstone Area (GYA) under alternative IPCC future scenarios; 2. Improve...
Integrating Climate and Biological Data into Management Decisions for the Greater Sage-Grouse and their Habitats
Climate affects both the demographics of the Greater sage-grouse bird and the condition and long-term viability of their habitats, including sage-steppe communities. This project builds on collaboration among federal land managers, state wildlife biologists, scientists, and other organizations to create a long-term framework for implementing adaptive management for the sage-grouse. The study...
Broad-scale surface and atmospheric conditions during large fires in south-central Chile
The unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares of central Chile highlight a need to better understand the climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric conditions at the surface and free troposphere associated with anomalously high (active) versus low (inactive) months...
McWethy, David B.; Garreaud, René; Holz, Andrés; Pederson, Gregory T. Climate drivers of large magnitude snow avalanche years in the U.S. northern Rocky Mountains
Large magnitude snow avalanches pose a hazard to humans and infrastructure worldwide. Analyzing the spatiotemporal behavior of avalanches and the contributory climate factors is important for understanding historical variability in climate-avalanche relationships as well as improving avalanche forecasting. We used established dendrochronological...
Peitzsch, Erich; Pederson, Gregory T.; Birkeland, Karl W.; Hendrikx, Jordy; Fagre, Daniel B. Growth and defense characteristics of whitebark pine (Pinus albicaulis) and lodgepole pine (Pinus contorta var latifolia) in a high-elevation, disturbance-prone mixed-conifer forest in northwestern Montana, USA
Recent, widespread tree mortality in the western U.S. resulting from changes in climate, pathogens, insect activity, and forest management practices has led to concerns for many ecologically and culturally important species. Within conifers, resin-based defenses have long been recognized as a primary defense mechanism against a variety of insects...
Kichas, Nicholas E.; Trowbridge, Amy M.; Raffa, Kenneth F.; Malone, Shealyn C.; Hood, Sharon M.; Everett, Richard G.; McWethy, David B.; Pederson, Gregory T. Water reliability in the west -- SECURE Water Act Section 9503(C)
No abstract available.
McGuire, Marketa; Gangopadhyay, Subhrendu; Martin, Justin; Pederson, Gregory T.; Woodhouse, Connie A.; Littell, Jeremy S. A regional spatio-temporal analysis of large magnitude snow avalanches using tree rings
Snow avalanches affect transportation corridors and settlements worldwide. In many mountainous regions, robust records of avalanche frequency and magnitude are sparse or non-existent. However, dendrochronological methods can be used to fill this gap and infer historical avalanche patterns. In this study, we developed a tree-ring-based avalanche...
Peitzsch, Erich; Hendrikx, Jordy; Stahle, Daniel Kent; Pederson, Gregory T.; Birkeland, Karl W.; Fagre, Daniel B. Snowpack signals in North American tree rings
Climate change has contributed to recent declines in mountain snowpack and earlier runoff, which in turn has intensified hydrological droughts in western North America. Climate model projections suggest that continued and severe snowpack reductions are expected over the 21st century, with profound consequences for ecosystems and human welfare. Yet...
Coulthard, Bethany L.; Anchukaitis, Kevin J.; Pederson, Gregory T.; Cook, Edward R; Littell, Jeremy S.; Smith, Dan J. Upper Colorado River Basin 20th century droughts under 21st century warming: Plausible scenarios for the future
This study builds on a collaboration with a water resource management community of practice in the Upper Colorado River Basin to develop scenarios of future drought and assess impacts on water supply reliability. Water managers are concerned with the impacts of warming on water year streamflow, but uncertainties in projections of climate make the...
Woodhouse, Connie A.; Smith, Rebecca M.; McAfee, Stephanie A.; Pederson, Gregory T.; McCabe, Gregory J.; Miller, W. Paul; Csank, Adam High elevation ice patch documents Holocene climate variability in the northern Rocky Mountains
Paleoclimate records from ice cores generally are considered to be the most direct indicators of environmental change, but are rare from mid-latitude, continental regions such as the western United States. High-elevation ice patches are known to be important archaeological archives in alpine regions and potentially could provide records important...
Chellman, Nathan J.; Pederson, Gregory T.; Lee, Craig; McWethy, Dave; Pusman, Kathryn; Stone, Jeffery R.; Brown, Sabrina R.; McConnell, Joseph R. Yellowstone's Old Faithful Geyser shut down by a severe 13th century drought
To characterize eruption activity of the iconic Old Faithful Geyser in Yellowstone National Park over past centuries, we obtained 41 new radiocarbon dates of mineralized wood preserved in the mound of silica that precipitated from erupted waters. Trees do not grow on active geyser mounds, implying that trees grew on the Old Faithful Geyser mound...
Hurwitz, Shaul; King, John; Pederson, Gregory T.; Martin, Justin; Damby, David; Manga, Michael; Hungerford, Jefferson; Peek, Sara Does signal-free detrending increase chronology coherence in large tree-ring networks?
Over the past decade, dendrochronologists have increasingly adopted the signal-free detrending (SFD) method to remove age-size trends in tree-ring measurement series, amplify the common stand-wide signal in composite chronologies, and recover medium- to low-frequency patterns that may be inadvertently removed by other detrending approaches....
McPartland, M.Y.; St. George, Scott; Pederson, Gregory T.; Anchukaitis, K.J. 2,200-Year tree-ring and lake-sediment based snowpack reconstruction for the northern Rocky Mountains highlights the historic magnitude of recent snow drought
In recent decades, Rocky Mountain accumulated snowpack levels have experienced rapid declines, yet long-term records of snowpack prior to the installation of snowpack observation stations in the early and mid 20th century are limited. To date, a small number of tree-ring based reconstructions of April 1 Snow Water Equivalent (SWE) in the northern...
Schoenemann, Spruce W.; Martin, Justin; Pederson, Gregory T.; McWethy, David B. Increased drought severity tracks warming in the United States’ largest river basin
Across the Upper Missouri River Basin, the recent drought of 2000 to 2010, known as the “turn-of-the-century drought,” was likely more severe than any in the instrumental record including the Dust Bowl drought. However, until now, adequate proxy records needed to better understand this event with regard to long-term variability have been lacking....
Martin, Justin; Pederson, Gregory T.; Woodhouse, Connie A.; Cook, Edward R.; McCabe, Gregory J.; Anchukaitis, Kevin J.; Wise, Erika K.; Erger, Patrick; Dolan, Larry S.; McGuire, Marketa; Gangopadhyay, Subhrendu; Chase, Katherine J.; Littell, Jeremy S.; Gray, Stephen; St. George, Scott; Friedman, Jonathan M.; Sauchyn, David J.; St. Jacques, Jeannine-Marie; King, John C.
A time when Old Faithful wasn’t so faithful
Old Faithful Geyser got its unique name in the 19th century because its eruptions were so regular and predictable. But during parts of the 13th and 14th centuries, the geyser did not erupt at all.