Greg Pederson, Ph.D.
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.
Research Interests
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.
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]
Education and Certifications
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
Affiliations and Memberships*
Greg is affiliate faculty with the Earth Sciences department and the Institute on Ecosystems (IoE) at Montana State University.
Science and Products
1200 years of Upper Missouri River streamflow reconstructed from tree rings
Streamflow reconstruction in the Upper Missouri River Basin using a novel Bayesian network model
An integrated framework for ecological drought across riverscapes of North America
Risks of hydroclimatic regime shifts across the western United States
Changing station coverage impacts temperature trends in the Upper Colorado River Basin
Identifying major avalanche years from a regional tree-ring based avalanche chronology for the U.S. Northern Rocky Mountains
Placing the Common Era in a Holocene context: Millennial to centennial patterns and trends in the hydroclimate of North America over the past 2000 years
Hydroclimatology of the Missouri River basin
Investigating runoff efficiency in upper Colorado River streamflow over past centuries
Evidence that recent warming is reducing upper Colorado River flows
Application of synthetic scenarios to address water resource concerns: A management-guided case study from the Upper Colorado River Basin
A global multiproxy database for temperature reconstructions of the Common Era
Science and Products
- Science
- Data
- Multimedia
- Publications
Filter Total Items: 58
1200 years of Upper Missouri River streamflow reconstructed from tree rings
Paleohydrologic records can provide unique, long-term perspectives on streamflow variability and hydroclimate for use in water resource planning. Such long-term records can also play a key role in placing both present day events and projected future conditions into a broader context than that offered by instrumental observations. However, relative to other major river basins across the western UAuthorsJustin Martin, Gregory T. Pederson, Connie A. Woodhouse, Edward R Cook, Gregory J. McCabe, Erika K. Wise, Patrick Erger, Larry Dolan, Marketa McGuire, Subhrendu Gangopadhyay, Katherine J. Chase, Jeremy Littell, Stephen Gray, Scott St. George, Jonathan M. Friedman, David J. Sauchyn, Jannine St. Jacques, John W. KingStreamflow reconstruction in the Upper Missouri River Basin using a novel Bayesian network model
A Bayesian model that uses the spatial dependence induced by the river network topology, and the leading principal components of regional tree-ring chronologies for paleo-streamflow reconstruction is presented. In any river basin, a convergent, dendritic network of tributaries comes together to form the main stem of a river. Consequently, it is natural to think of a spatial Markov process that rAuthorsArun Ravindranath, Naresh Devineni, Upmanu Lall, Edward Cook, Gregory T. Pederson, Justin Martin, Connie A. WoodhouseAn integrated framework for ecological drought across riverscapes of North America
Climate change is increasing the severity and extent of extreme droughts events, posing a critical threat to freshwater ecosystems, particularly with increasing human demands for diminishing water supplies. Despite the importance of drought as a significant driver of ecological and evolutionary dynamics, current understanding of drought consequences for freshwater biodiversity is very limited. WAuthorsRyan Kovach, Jason B. Dunham, Robert Al-Chokhachy, Craig Snyder, Erik A. Beever, Gregory T. Pederson, Abigail Lynch, Nathaniel P. Hitt, Christopher P. Konrad, Kristin Jaeger, Alan H. Rea, Adam J. Sepulveda, Patrick M. Lambert, Jason M. Stoker, J. Joseph Giersch, Clint C. MuhlfeldRisks of hydroclimatic regime shifts across the western United States
Paleohydrologic reconstructions of water-year streamflow for 105 sites across the western United States (West) were used to compute the likelihood (risk) of regime (wet/dry state) shifts given the length of time in a specific regime and for a specified time in the future. The spatial variability of risks was examined and indicates that regime shift risks are variable across the West. The Pacific-NAuthorsSubhrendu Gangopadhyay, Gregory J. McCabe, Gregory T. Pederson, Justin Martin, Jeremy S. LittellChanging station coverage impacts temperature trends in the Upper Colorado River Basin
Over the Upper Colorado River Basin (UCRB), temperatures in widely used gridded data products do not warm as much as mean temperatures from a stable set of U.S. Historical Climatology Network (USHCN) stations, located at generally lower elevations, in most months of the year. This is contrary to expectations of elevation-dependent warming, which suggests that warming increases with elevation. ThesAuthorsStephanie A. McAfee, Gregory J. McCabe, Stephen Gray, Gregory T. PedersonIdentifying major avalanche years from a regional tree-ring based avalanche chronology for the U.S. Northern Rocky Mountains
Avalanches not only pose a major hazard to people and infrastructure, but also act as an important ecological disturbance. In many mountainous regions in North America, including areas with existing transportation corridors, reliable and consistent avalanche records are sparse or non-existent. Thus, inferring long-term avalanche patterns and associated contributory climate and weather factors reAuthorsErich H. Peitzsch, Daniel B. Fagre, Gregory T. Pederson, Jordy Hendrikx, Karl W. Birkeland, Daniel StahlePlacing the Common Era in a Holocene context: Millennial to centennial patterns and trends in the hydroclimate of North America over the past 2000 years
A synthesis of 93 hydrologic records from across North and Central America, and adjacent tropical and Arctic islands, reveals centennial to millennial trends in the regional hydroclimates of the Common Era (CE; past 2000 years). The hydrological records derive from materials stored in lakes, bogs, caves, and ice from extant glaciers, which have the continuity through time to preserve low-frequencyAuthorsBryan Shuman, Cody C. Routson, Nicholas P. McKay, Sherilyn Fritz, Darrell S. Kaufman, Matthew Kirby, Connor Nolan, Gregory T. Pederson, Jeannine-Marie St. JacquesHydroclimatology of the Missouri River basin
Despite the importance of the Missouri River for navigation, recreation, habitat, hydroelectric power, and agriculture, relatively little is known about the basic hydroclimatology of the Missouri River basin (MRB). This is of particular concern given the droughts and floods that have occurred over the past several decades and the potential future exacerbation of these extremes by climate change. HAuthorsErika K. Wise, Connie A. Woodhouse, Gregory J. McCabe, Gregory T. Pederson, Jeannine-Marie St. JacquesInvestigating runoff efficiency in upper Colorado River streamflow over past centuries
With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid to the relationship between runoff and precipitation, or runoff efficiency. Temperature is a key influence on Colorado River runoff efficiency, and warming temperatures are projected to reduce runoff efficiency. Here, we investigate the nature of runoff efficiency in the upper ColoradAuthorsConnie A. Woodhouse, Gregory T. PedersonEvidence that recent warming is reducing upper Colorado River flows
The upper Colorado River basin (UCRB) is one of the primary sources of water for the western United States, and increasing temperatures likely will elevate the risk of reduced water supply in the basin. Although variability in water-year precipitation explains more of the variability in water-year UCRB streamflow than water-year UCRB temperature, since the late 1980s, increases in temperature in tAuthorsGregory J. McCabe, David M. Wolock, Gregory T. Pederson, Connie A. Woodhouse, Stephanie A. McAfeeApplication of synthetic scenarios to address water resource concerns: A management-guided case study from the Upper Colorado River Basin
Water managers are increasingly interested in better understanding and planning for projected resource impacts from climate change. In this management-guided study, we use a very large suite of synthetic climate scenarios in a statistical modeling framework to simultaneously evaluate how (1) average temperature and precipitation changes, (2) initial basin conditions, and (3) temporal characteristiAuthorsStephanie A. McAfee, Gregory T. Pederson, Connie A. Woodhouse, Gregory J. McCabeA global multiproxy database for temperature reconstructions of the Common Era
Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The recordsAuthorsJulian Emile-Geay, Nicholas P. McKay, Darrell S. Kaufman, Lucien von Gunten, Jianghao Wang, Kevin J. Anchukaitis, Nerilie J. Abram, Jason A. Addison, Mark A.J. Curran, Michael N. Evans, Benjamin J. Henley, Zhixin Hao, Belen Martrat, Helen V. McGregor, Raphael Neukom, Gregory T. Pederson, Barbara Stenni, Kaustubh Thirumalai, Johannes P. Werner, Chenxi Xu, Dmitry V. Divine, Bronwyn C. Dixon, Joelle Gergis, Ignacio A. Mundo, T. Nakatsuka, Steven J. Phipps, Cody C. Routson, Eric J. Steig, Jessica E. Tierney, Jonathan J. Tyler, Kathryn J. Allen, Nancy A. N. Bertler, Jesper Bjorklund, Brian M. Chase, Min-Te Chen, Ed Cook, Rixt de Jong, Kristine L. DeLong, Daniel A. Dixon, Alexey A. Ekaykin, Vasile Ersek, Helena L. Filipsson, Pierre Francus, Mandy B. Freund, M. Frezzotti, Narayan P. Gaire, Konrad Gajewski, Quansheng Ge, Hugues Goosse, Anastasia Gornostaeva, Martin Grosjean, Kazuho Horiuchi, Anne Hormes, Katrine Husum, Elisabeth Isaksson, Selvaraj Kandasamy, Kenji Kawamura, Nalan Koc, Guillaume Leduc, Hans W. Linderholm, Andrew M. Lorrey, Vladimir Mikhalenko, P. Graham Mortyn, Hideaki Motoyama, Andrew D. Moy, Robert Mulvaney, Philipp M. Munz, David J. Nash, Hans Oerter, Thomas Opel, Anais J. Orsi, Dmitriy V. Ovchinnikov, Trevor J. Porter, Heidi Roop, Casey Saenger, Masaki Sano, David Sauchyn, K.M. Saunders, Marit-Solveig Seidenkrantz, Mirko Severi, X. Shao, Marie-Alexandrine Sicre, Michael Sigl, Kate Sinclair, Scott St. George, Jeannine-Marie St. Jacques, Meloth Thamban, Udya Kuwar Thapa, E. Thomas, Chris Turney, Ryu Uemura, A.E. Viau, Diana O. Vladimirova, Eugene Wahl, James W. C. White, Z. Yu, Jens Zinke - News
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government