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Sarah Shafer

Sarah Shafer is a Research Geologist for the Geosciences and Environmental Change Science Center

Science and Products

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Growing Degree Days

Exploring Future Flora, Environments, and Climates Through Simulations (EFFECTS)

Climate changes can significantly affect species and ecosystems. Historical and paleoenvironmental data record species and ecosystem responses to past climate changes, but these records become sparse as one goes further back in time. Model simulations can be used fill the spatial and temporal gaps in observed records to improve our understanding of the potential magnitude, rate, and spatial...
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Climate Research and Development Program, Geosciences and Environmental Change Science Center
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Exploring Future Flora, Environments, and Climates Through Simulations (EFFECTS)

Climate changes can significantly affect species and ecosystems. Historical and paleoenvironmental data record species and ecosystem responses to past climate changes, but these records become sparse as one goes further back in time. Model simulations can be used fill the spatial and temporal gaps in observed records to improve our understanding of the potential magnitude, rate, and spatial...
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Image: Rocky Mountain National Park

A Visualization Approach for Projecting Future Climate Distributions in North America

Conservation and natural resource managers require information about potential future climate changes for the areas they manage, in terms that are relevant for the specific biotic and environmental resources likely to be affected by climate change. We produced a suite of data sets that provide managers with climate and climate-derived data and a visualization approach that allows managers to map w
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Climate Adaptation Science Centers
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A Visualization Approach for Projecting Future Climate Distributions in North America

Conservation and natural resource managers require information about potential future climate changes for the areas they manage, in terms that are relevant for the specific biotic and environmental resources likely to be affected by climate change. We produced a suite of data sets that provide managers with climate and climate-derived data and a visualization approach that allows managers to map w
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Lake and forest landscape in Mt. Rainier National Park

Assessing the Vulnerability of Species and Ecosystems to Projected Future Climate Change in the Pacific Northwest

To develop effective adaptive management plans, conservation and natural resource managers need to know how climate change will affect the species and ecosystems they manage. This project provides managers with information about potential climate change effects on species and managed areas in the Pacific Northwest. We evaluated projected changes in climate, vegetation, and species distributions th
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Climate Adaptation Science Centers
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Assessing the Vulnerability of Species and Ecosystems to Projected Future Climate Change in the Pacific Northwest

To develop effective adaptive management plans, conservation and natural resource managers need to know how climate change will affect the species and ecosystems they manage. This project provides managers with information about potential climate change effects on species and managed areas in the Pacific Northwest. We evaluated projected changes in climate, vegetation, and species distributions th
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PMIP3/CMIP5 lgm simulated temperature data for North America downscaled to a 10-km grid

This data set consists of monthly long-term mean temperature data (degrees C) for the last glacial maximum (21 ka) downscaled to a 10-km grid of North America. The 10-km data were derived using simulated temperature data from 10 general circulation models (GCMs; CCSM4, CNRM-CM5, COSMOS-ASO, FGOALS-g2, GISS-E2-R, IPSL-CM5A-LR, MIROC-ESM, MPI-ESM-P-OA, MPI-ESM-P-OAC, and MRI-CGCM3) run under the PM
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Geosciences and Environmental Change Science Center

USGS North American Packrat Midden Database, Version 5.0

This data release contains the data tables for the USGS North American Packrat Midden Database (version 5.0). This version of the Midden Database contains data for 3,331 packrat midden samples obtained from published sources (journal articles, book chapters, theses, dissertations, government and private industry reports, conference proceedings) as well as unpublished data contributed by researche
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Geosciences and Environmental Change Science Center

Global biomes for the Last Interglacial period (127-119 ka) simulated by BIOME4 using CESM2-CISM2 coupled climate–ice sheet model data

This data release contains: 1) the BIOME4-simulated biome data used to create Sommers et al. (2021) Figures 2, 6, S6, and S7; 2) the CESM2-CISM2 calendar-adjusted temperature data used to create Sommers et al. (2021) Figures 2, 7, S2-S5, and S8-S11; and 3) land, ice, and ocean mask data and continent and ice sheet outline files. Additional CESM2-CISM2 simulation data described in Sommers et al. (
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Biomes simulated by BIOME4 using CESM2 lig127k, midHolocene, and piControl climate data on a global 0.5-degree grid

This data set consists of simulated biomes for the last interglacial (127 ka), middle Holocene (6 ka), and preindustrial (1850 CE) time periods displayed in Figure 14 of Otto-Bliesner et al. (2020). Biomes were simulated with BIOME4 (ver. 4.2, https://pmip2.lsce.ipsl.fr/synth/biome4.shtml; Kaplan et al., 2003), an equilibrium vegetation model, using CESM2 (ver. 2.1.0) simulated climate data produ
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Geosciences and Environmental Change Science Center

Propensity of cold air drainage index and related variables

Cold air drainage down slopes may form cold air pools in valleys and surface depressions. These cold air pools can significantly affect ecosystem processes, agricultural crops, and air quality. Rupp et al. (2021, Theoretical and Applied Climatology, https://doi.org/10.1007/s00704-021-03712-y) proposed a propensity of cold air drainage index to represent the likelihood of occurrence of clear-sky no
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Geosciences and Environmental Change Science Center

Data release for Assessing the Uncertainties in Climatic Estimates Based on Vegetation Assemblages: Examples from Modern Vegetation Assemblages in the American Southwest

This data release includes climatic variables and associated descriptive material created for the purpose of assessing uncertainties associated with climatic estimates based on vegetation assemblages (Thompson and others, 2021). The data are from the interior of the western United States, including all of Arizona, and portions of California, Colorado, Nevada, New Mexico, Texas, and Utah. The data
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Statistically-downscaled monthly historical (1901-2000) CRU TS 2.1 and projected future (2001-2099) CMIP3 A2 and A1B simulated temperature, precipitation, and sunshine data on a 30-second grid of the northwest United States and southwest Canada, version 1

This data set consists of monthly mean temperature (degrees C), total precipitation (mm), and possible sunshine (%) data statistically downscaled onto a 30-second grid of the northwest United States and southwest Canada. Historical climate data for 1901-2000 were developed from the CRU CL 1.0, CRU CL 2.0, and CRU TS 2.1 data sets (http://www.cru.uea.ac.uk/cru/data/hrg/). Projected future climate d
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Geosciences and Environmental Change Science Center

Bioclimatic variables calculated from statistically-downscaled historical (1901-2000) CRU TS 2.1 climate data and projected future (2001-2099) CMIP3 A2 and A1B simulated climate data on a 30-second grid of the northwest United States and southwest Canada,

This data set consists of a set of bioclimatic variables calculated from monthly mean temperature (degrees C), total precipitation (mm), and possible sunshine (%) data on a 30-second grid of the northwest United States and southwest Canada. Historical climate data for 1901-2000 were developed from the CRU CL 1.0, CRU CL 2.0, and CRU TS 2.1 data sets (http://www.cru.uea.ac.uk/cru/data/hrg/). Projec
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Geosciences and Environmental Change Science Center

LPJ biomes (30-year mean) simulated using monthly historical (1901-2000) CRU TS 2.1 climate data and projected future (2001-2099) CMIP3 A2 and A1B simulated climate data on a 30-second grid of the northwest United States and southwest Canada, version 1.0

This data set consists of biomes (30-year mean) simulated using LPJ, a dynamic global vegetation model (Sitch et al. 2003, Global Change Biology 9:161-185), for a 30-second grid of the northwest United States and southwest Canada. Shafer et al. (2015, PLoS ONE 10: e0138759) describe the methods used to create the biome data. LPJ was run for 1901-2000 using historical climate data developed from th
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Geosciences and Environmental Change Science Center
Filter Total Items: 37

Plant macrofossil data for 48-0 ka in the USGS North American Packrat Midden Database, version 5.0

Plant macrofossils from packrat (Neotoma spp.) middens provide direct evidence of past vegetation changes in arid regions of North America. Here we describe the newest version (version 5.0) of the U.S. Geological Survey (USGS) North American Packrat Midden Database. The database contains published and contributed data from 3,331 midden samples collected in southwest Canada, the western United Stat
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Laura E. Strickland, Robert S. Thompson, Sarah Shafer, Patrick J. Bartlein, Richard T. Pelltier, Katherine H Anderson, R. Randall Schumann, Andrew K. McFadden
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Geosciences and Environmental Change Science Center

Retreat and regrowth of the Greenland Ice Sheet during the Last Interglacial as simulated by the CESM2-CISM2 coupled climate–ice sheet model

During the Last Interglacial, approximately 129 to 116 ka (thousand years ago), the Arctic summer climate was warmer than the present, and the Greenland Ice Sheet retreated to a smaller extent than its current state. Previous model-derived and geological reconstruction estimates of the sea-level contribution of the Greenland Ice Sheet during the Last Interglacial vary widely. Here, we conduct a tr
Authors
Aleah Sommers, Bette L. Otto-Bliesner, William Lipscomb, Marcus Lofverstrom, Sarah Shafer, Patrick J. Bartlein, Esther C. Brady, Erik Kluzek, Gunter Leguy, Katherine Thayer-Calder, Robert Tomas
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Assessing the uncertainties in climatic estimates based on vegetation assemblages: Examples from modern vegetation assemblages in the American Southwest

Assemblages of fossil plant remains have been widely used to reconstruct past climatic conditions, usually through the application of methods that involve either finding vegetation analogues on the modern landscape (and using the modern associated climatic values as the basis for an estimate) or using the modern climatic ranges of individual taxa in an assemblage to determine the range of a given
Authors
Robert S. Thompson, Katherine H Anderson, Richard T. Pelltier, Laura E. Strickland, Sarah Shafer, Patrick J. Bartlein
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Extensive frost weathering across unglaciated North America during the Last Glacial Maximum

In unglaciated terrain, the imprint of past glacial periods is difficult to discern. The topographic signature of periglacial processes, such as solifluction lobes, may be erased or hidden by time and vegetation, and thus their import diminished. Belowground, periglacial weathering, particularly frost cracking, may have imparted a profound influence on weathering and erosion rates during past clim
Authors
Jill J Marshall, Joshua J. Roering, Alan W. Rempel, Sarah Shafer, Patrick J. Bartlein
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Geosciences and Environmental Change Science Center

A comparison of the CMIP6 midHolocene and lig127k simulations in CESM2

Results are presented and compared for the Community Earth System Model version 2 (CESM2) simulations of the middle Holocene (MH, 6 ka) and Last Interglacial (LIG, 127 ka). These simulations are designated as Tier 1 experiments (midHolocene and lig127k) for the Coupled Model Intercomparison Project phase 6 (CMIP6) and the Paleoclimate Modeling Intercomparison Project phase 4 (PMIP4). They use the
Authors
Bette L. Otto-Bliesner, Esther C. Brady, Robert A Tomas, Samuel Albani, Patrick J. Bartlein, Natalie M Mahowald, Sarah Shafer, Erik Kluzek, Peter J Lawrence, Gunter Leguy, Matthew Rothstein, Aleah Sommers
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Geosciences and Environmental Change Science Center

Understanding the uncertainty in global forest carbon turnover

The length of time that carbon remains in forest biomass is one of the largest uncertainties in the global carbon cycle, with both recent historical baselines and future responses to environmental change poorly constrained by available observations. In the absence of large-scale observations, models used for global assessments tend to fall back on simplified assumptions of the turnover rates of bi
Authors
Thomas A. M. Pugh, Tim Tito Rademacher, Sarah Shafer, Jörg Steinkamp, Jonathan Barichivich, Brian Beckage, Vanessa Haverd, Anna Harper, Jens Heinke, Kazuya Nishina, Anja Rammig, Hisashi Sato, Almut Arneth, Stijn Hantson, Thomas Hickler, Markus Kautz, Benjamin Quesada, Benjamin Smith, Kirsten Thonicke
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Geosciences and Environmental Change Science Center

Paleo calendar-effect adjustments in time-slice and transient climate-model simulations (PaleoCalAdjust v1.0): Impact and strategies for data analysis

The “paleo calendar effect” is a common expression for the impact that changes in the length of months or seasons over time, related to changes in the eccentricity of Earth's orbit and precession, have on the analysis or summarization of climate-model output. This effect can have significant implications for paleoclimate analyses. In particular, using a “fixed-length” definition of months (i.e., d
Authors
Patrick J. Bartlein, Sarah Shafer
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Geosciences and Environmental Change Science Center

Projected future vegetation changes for the northwest United States and southwest Canada at a fine spatial resolution using a dynamic global vegetation model.

Future climate change may significantly alter the distributions of many plant taxa. The effects of climate change may be particularly large in mountainous regions where climate can vary significantly with elevation. Understanding potential future vegetation changes in these regions requires methods that can resolve vegetation responses to climate change at fine spatial resolutions. We used LPJ, a
Authors
Sarah Shafer, Patrick J. Bartlein, Elizabeth M. Gray, Richard T. Pelltier
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Climate Research and Development Program, Groundwater and Streamflow Information Program, Land Change Science Program, Geosciences and Environmental Change Science Center

Early-Holocene warming in Beringia and its mediation by sea-level and vegetation changes

Arctic land-cover changes induced by recent global climate change (e.g., expansion of woody vegetation into tundra and effects of permafrost degradation) are expected to generate further feedbacks to the climate system. Past changes can be used to assess our understanding of feedback mechanisms through a combination of process modeling and paleo-observations. The subcontinental region of Beringia
Authors
P. J. Bartlein, M. E. Edwards, Steven W. Hostetler, Sarah Shafer, P. M. Anderson, L. B Brubaker, A. V Lozhkin
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Water Resources Mission Area, Geosciences and Environmental Change Science Center

Comparing ecoregional classifications for natural areas management in the Klamath Region, USA

We compared three existing ecoregional classification schemes (Bailey, Omernik, and World Wildlife Fund) with two derived schemes (Omernik Revised and Climate Zones) to explore their effectiveness in explaining species distributions and to better understand natural resource geography in the Klamath Region, USA. We analyzed presence/absence data derived from digital distribution maps for trees, amp
Authors
Daniel A. Sarr, Andrew Duff, Eric C. Dinger, Sarah L. Shafer, Michael Wing, Nathaniel E. Seavy, John D. Alexander
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Geosciences and Environmental Change Science Center

Atlas of relations between climatic parameters and distributions of important trees and shrubs in North America: Revisions for all taxa from the United States and Canada and new taxa from the western United States

This is the seventh volume in an atlas series that explores the relations between the geographic distributions of woody plant species and climatic variables in North America. A 25-kilometer (km) equal-area grid of modern climatic and bioclimatic variables was constructed from weather data. The geographic distributions of selected tree and shrub species were digitized, and the presence or absence o
Authors
Robert S. Thompson, Katherine H. Anderson, Richard T. Pelltier, Laura E. Strickland, Sarah L. Shafer, Patrick J. Bartlein, Andrew K. McFadden
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Climate Research and Development Program, Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

U.S. Geological Survey Science for the Wyoming Landscape Conservation Initiative: 2012 annual report

Southwest Wyoming contains abundant energy resources, wildlife, habitat, open spaces, and outdoor recreational opportunities. Although energy exploration and development have been taking place in the region since the late 1800s, the pace of development for fossil fuels and renewable energy increased significantly in the early 2000s. This and the associated urban and exurban development are leading
Authors
Zachary H. Bowen, Cameron L. Aldridge, Patrick J. Anderson, Timothy J. Assal, Carleton R. Bern, Laura Biewick, Gregory K. Boughton, Natasha B. Carr, Anna D. Chalfoun, Geneva W. Chong, Melanie L. Clark, Bradford C. Fedy, Katharine Foster, Steven L. Garman, Steve Germaine, Matthew G. Hethcoat, Collin G. Homer, Matthew J. Kauffman, Douglas Keinath, Natalie Latysh, Daniel J. Manier, Robert R. McDougal, Cynthia P. Melcher, Kirk A. Miller, Jessica Montag, Christopher J. Potter, Spencer Schell, Sarah L. Shafer, David B. Smith, Michael J. Sweat, Anna B. Wilson
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Ecosystems Mission Area, Fort Collins Science Center, Geosciences and Environmental Change Science Center

Science and Products