The tree rings in this whitebark pine (Pinus albicaulis) cross-section provide a view back in time. Scientists study the patterns of tree ring growth, scars, and wood coloration to determine how long the tree lived, record changes in climate, and even track past fires, insect attacks, and earthquakes!
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]
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...
Characterizing Historic Streamflow to Support Drought Planning in the Upper Missouri River Basin
The Missouri River system is the life-blood of the American Midwest, providing critical water resources that drive the region’s agriculture, industry, hydroelectric power generation, and ecosystems. The basin has a long history of development and diversion of water resources, meaning that streamflow records that reflect natural, unmanaged flows over the past century have been rare. As a result, re
Anticipating Future Impacts of Temperature on Streamflow in the Colorado River Basin
The Colorado River is a crucial water source for millions of people in the Southwest. Warming temperatures, clearly documented in climate records for the Colorado River basin, are having an impact on the amount of annual streamflow yielded from rain and snow. Recent work has revealed that warming temperatures have played an increasingly important role over the past decades, both exacerbating droug
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 Northern...
Examining the Influence of Temperature and Precipitation on Colorado River Water Resources: Reconstructing the Past to Understand the Future
Streamflow in the Colorado River is heavily influenced by high-elevation snowpack. Warming temperatures in spring can reduce snow-fed flows, with serious implications for the water supplies that support communities and wildlife. While it is already well-known that precipitation has a significant influence on river flow, recent observations suggest that temperature and the amount of water in soil m
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 extend
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 und
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 exami
Cross-section of Whitebark Pine
The tree rings in this whitebark pine (Pinus albicaulis) cross-section provide a view back in time. Scientists study the patterns of tree ring growth, scars, and wood coloration to determine how long the tree lived, record changes in climate, and even track past fires, insect attacks, and earthquakes!
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...
Characterizing Historic Streamflow to Support Drought Planning in the Upper Missouri River Basin
The Missouri River system is the life-blood of the American Midwest, providing critical water resources that drive the region’s agriculture, industry, hydroelectric power generation, and ecosystems. The basin has a long history of development and diversion of water resources, meaning that streamflow records that reflect natural, unmanaged flows over the past century have been rare. As a result, re
Anticipating Future Impacts of Temperature on Streamflow in the Colorado River Basin
The Colorado River is a crucial water source for millions of people in the Southwest. Warming temperatures, clearly documented in climate records for the Colorado River basin, are having an impact on the amount of annual streamflow yielded from rain and snow. Recent work has revealed that warming temperatures have played an increasingly important role over the past decades, both exacerbating droug
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 Northern...
Examining the Influence of Temperature and Precipitation on Colorado River Water Resources: Reconstructing the Past to Understand the Future
Streamflow in the Colorado River is heavily influenced by high-elevation snowpack. Warming temperatures in spring can reduce snow-fed flows, with serious implications for the water supplies that support communities and wildlife. While it is already well-known that precipitation has a significant influence on river flow, recent observations suggest that temperature and the amount of water in soil m
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 extend
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 und
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 exami
Cross-section of Whitebark Pine
The tree rings in this whitebark pine (Pinus albicaulis) cross-section provide a view back in time. Scientists study the patterns of tree ring growth, scars, and wood coloration to determine how long the tree lived, record changes in climate, and even track past fires, insect attacks, and earthquakes!
The tree rings in this whitebark pine (Pinus albicaulis) cross-section provide a view back in time. Scientists study the patterns of tree ring growth, scars, and wood coloration to determine how long the tree lived, record changes in climate, and even track past fires, insect attacks, and earthquakes!
*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