Executive Summary: Paleoclimate

Sedimentary records from continental and coastal environments recovered through scientific drilling provide rich archives of climate history at spatial and temporal scales relevant to current and future societies. Anthropogenic global change has stressed societies through changes in temperature and the water cycle (Intergovernmental Panel on Climate Change AR6 Synthesis Report, 2023). Future climate trajectories may lie outside natural and/or preindustrial conditions and may be irreversible on centennial time scales, making historic and instrumental data insufficient to adequately anticipate hazards. Prominent examples include rising sea level and depleted surface and groundwater resources that likely will not be recharged in the coming centuries. The temporal scope provided by sedimentary archives that record climate history, and reflect local to global processes, is necessary for anchoring model-based predictions. This information is especially needed for studies of key warm periods and abrupt climate transitions, particularly those under higher CO2, for both Quaternary and deep geological timescales. Moreover, given the importance of water to human well-being and life on this planet, it is critical to provide reliable and societally relevant information about past hyperthermal and hydroclimate events at various temporal scales via a strategically distributed network of continental reconstructions. Because people inhabit continents, compelling paleoclimate questions remain about fundamental climate system dynamics that only continental drilling can address.

What are the drivers and feedbacks of the Earth’s system during times when climate veered to alternative states?

The level at which Earth is instrumented, observed, and modeled has radically advanced our knowledge of recent and ongoing climate change, but this knowledge lends a false sense of sophistication to our understanding of Earth-system behavior. The geological record has revealed repeated examples of seemingly ‘other-worldly’ climate scenarios — times when Earth’s climate evolved in surprising, even unimaginable, ways. The data tell us that extreme states occurred – e.g., complete ice coverage, no ice coverage, and times when polar and equatorial temperatures were similar – but there are outstanding questions about forcings, feedbacks, and tipping points that led to these scenarios. An understanding of these geological intervals is increasingly relevant as we enter a period of unprecedented climate conditions. Earth’s continental sedimentary archives can be used to develop proxy records, often at higher resolution than marine records and extending deeper in time than ice cores, that in turn can test hypotheses and further elucidate past climate states at local to global scales. Continental paleorecords allow us to investigate alternative Earth-system states as they impacted the continents such as: 1) past warm periods including Quaternary interglacials, the Pliocene warm period, the Miocene climatic optimum, the early Eocene, the Paleocene-Eocene Thermal Maximum (PETM), and Late Cretaceous peak warmth, and 2) times when configurations and forcings were quite different than those of today, including the Last Glacial Maximum and deglaciation, the Eocene-Oligocene transition, and earlier intervals during the Paleozoic. Newly developed continental climate records should span time-intervals characterized by varied tectonic configurations, ice coverage, vegetation, and sea level – essentially, intervals with different forcing factors.

What climatic teleconnections and feedbacks are revealed by past hydroclimatic change on a warming Earth?

Both theory and models predict that continued climate warming will produce intensification of the water cycle (increased extremes and variability) on a global scale. However, the scant hydroclimate records that do exist for a ‘hothouse’, high-CO2 Earth suggest that precipitation changes also include conversion of dry regions into wet regions, and vice versa, and documenting these effects in the past is critical for creating realistic scenarios for the future. In addition, observed variability in regional hydroclimate responses to changes in major forcings makes robust inferences about spatiotemporal teleconnections between forcing factors, such as ocean temperatures, and hydroclimate extremes difficult.

Targeted drilling of continental sites sensitive to hydroclimate changes will allow us to examine both past conditions and their drivers, providing a basis for deciphering hydroclimate, biological and carbon cycle feedbacks. Because continental climate records provide higher temporal resolution than ocean drill cores and higher spatial resolution than ice cores, they also offer opportunities to study short-lived and abrupt climate events. In relevant cases, targeted drilling will provide opportunities to integrate continental proxy records with coastal or marine sequences to better evaluate ocean linkages with continental climate change. In addition, focusing on past intervals of warming will provide clues on hydroclimate changes that could be crucial to anchor model-based predictions. Among many potential time-periods that could be studied, the early Eocene provides an opportunity to investigate continental hydroclimate changes with high CO2, global surface temperatures significantly higher than pre-industrial, and with different tectonic configurations than today. Alternatively, the Miocene and Pliocene epochs provide opportunities to investigate hydroclimate responses to higher atmospheric CO2 concentrations under tectonic configurations similar to today’s.

What resources are required?

Temporally-long, highly-resolved, and well-dated records needed to answer outstanding paleoclimate questions will require continental coring and drilling deeper and at more challenging sites than before. Obtaining these records will require funding opportunities with larger budget caps than core EAR programs and capability to carry out drilling at sites both on and off road networks. This requires flexibility in drilling operations and equipment and assistance with complex project logistics.

Suggested Citation

Obrist Farner, J., Anderson, L., Baker, P., Berke, M., Beverly, E., Brigham-Grette, J., Brown, E., Castaneda, I., Deino, Fritz, S., Goldstein, S., A., Kehrwald, N., Kirby, M., Miller, K., Olsen, P., Robinson, M., Russell, J., Soreghan, L., 2024. Paleoclimate Science Planning for Continental Drilling and Coring 2024. https://sites.google.com/umn.edu/csdscienceplanning/home/paleoclimate-executive-summary

Paleoclimate Working Group

Lesleigh Anderson, United States Geological Survey

Paul Baker, Duke University

Melissa Berke, University of Notre Dame

Emily Beverly, University of Minnesota

Julie Brigham-Grette, University of Massachusetts Amherst

Erik Brown, University of Minnesota Duluth

Isla Castaneda, University of Massachusetts Amherst

Al Deino, Berkeley Geochronology Center

Sherilyn Fritz, University of Nebraska Lincoln

Steven Goldstein, Lamont-Doherty Earth Observatory Columbia University

Natalie Kehrwald, United States Geological Survey

Matt Kirby, California State University Fullerton

David McGee, Massachusetts Institute of Technology

Kenneth Miller, Rutgers University

Johnathan Obrist Farner, Missouri University of Science and Technology

Paul Olsen, Lamont-Doherty Earth Observatory Columbia University

Marci Robinson, United States Geological Survey

James Russell, Brown University

Gerilyn Soreghan, University of Oklahoma

Paleoclimate Community Editors

Mark Abbott, University of Pittsburgh

Kevin Anchukiatis, University of Arizona

Gail Ashley, Rutgers University

Eliot Atekwana, University of California Davis

Alexis Ault, Utah State University

Jamila Baig, University of Oregon

Catherine Beck, Hamilton College

Andrey Bekker, University of California Riverside

Kathleen Benison, West Virginia University

Asmeret Asefaw Berhe, University of California Merced

Tripti Bhattacharya, Syracuse University

Broxton Bird, Indiana University

Jessica Blois, University of California Merced

David Boutt, University of Massachusetts

Janice Brahney, Utah State University

Latisha Brengman, University of Minnesota Duluth

Cedar Briem, Desert Research Institute

Andrea Brunelle, University of Utah

Chris Campisano, Arizona State University

Christine Chen, Lawrence Livermore National Laboratory

Victoria Chraibi, Tarleton State University

Douglas Clark, Western Washington University

Will Clyde, University of New Hampshire

Andy Cohen, University of Arizona

Marie-Helene Cormier, University of Rhode Island Graduate School of Oceanography

John Counts, United States Geological Survey

Brad Cramer, University of Iowa

Ellen Currano, University of Wyoming

Brandon Curry, Illinois State Geological Survey

Marieke Dechesne, United States Geological Survey

Andrea Dutton, University of Wisconsin Madison

Julien Emile-Geay, University of Southern California Dornsife

Peter Fawcett, University of New Mexico

Brady Foreman, Western Washington University

Sarah Fowell, University of Alaska Fairbanks

Jacquelyn Gill, University of Maine

Andrew Gillreath-Brown, Yale University

John Goodge, University of Minnesota Duluth

Simon Goring, University of Wisconsin Madison

David Greenwood, Brandon University

Dulcinea Groff, University of Maine

Robert Guralnick, University of Florida

Scott Harris, College of Charleston

Nicholas Heaven, Viridien

Clifford Heil, University of Rhode Island Graduate School of Oceanography

Yongsong Huang, Brown Univ

Scott Hynek, United States Geological Survey

Virginia Iglesias, University of Colorado Boulder

Randy Irmis, University of Utah

Emi Ito, University of Minnesota

Sarah Ivory, Penn State University

Britta Jensen, University of Alberta

Tom Johnson, University of Minnesota Duluth

Kathleen Johnson, University of California Irvine

Darrell Kaufman, Northern Arizona University

Dennis Kent, Lamont-Doherty Earth Observatory Columbia University

Sean Kinney, Rutgers University

Bronwen Konecky, Washington University in St. Louis

Stephen Kuehn, Concord University

Chad Lane, University of North Carolina Wilmington

Jennifer Latimer, Indiana State University

Kerstin Lehnert, Lamont-Doherty Earth Observatory Columbia University

Lonnie Leithold, North Carolina State University

Tim Lowenstein, Binghamton University

John Lukzaj, University Wisconsin Green Bay

Steve Lund, University Southern California Dornsife

Francis MacDonald, University of California Santa Barbara

David Marchetti, Western Colorado University

Shaun Marcott, University of Wisconsin Madison

Paul McCarthy, University of Alaska Fairbanks

Michael McGlue, University of Kentucky

Jenny McGuire, Georgia Institute of Technology

Nicholas McKay, Northern Arizona University

Jason McLachlan, University of Notre Dame

Isabel Montañez, University of California Davis

Leah Morgan, United States Geological Survey

LeeAnn Munk, University of Alaska Anchorage

Franca Oboh Ikuenobe, Missouri University of Science and Technology

Kristian Olson, Binghamton University

Molly Patterson, Binghamton University

Lily Pfeifer, Rowan University

Jeff Pietras, Binghamton University

Noah Planavsky, Yale University

Mitchell Power, University of Utah

Brendan Reilly, Lamont-Doherty Earth Observatory Columbia University

Alberto Reyes, University of Alberta

Kenneth Ridgway, Purdue University

Tammy Rittenour, Utah State University

Donald Rodbell, Union College

Jess Rodysill, United States Geological Survey

Dana Royer, Wesleyan University

Jean Self-Trail, United States Geological Survey

Bryan Shuman, University of Wyoming

Peter Siver, Connecticut College

Alison Smith, Kent State University

Trisha Spanbauer, University of Toledo

Byron Steinman, University of Minnesota Duluth

Jeffery Stone, Indiana State University

Joseph Stoner, Oregon State University

Laura Streib, Syracuse University

Justin Stroup, State University of New York Oswego

Celina Suarez, University of Arkansas

Frederick Taylor, University Texas Austin

Zachary Taylor, Berry College

Rebecca Teed, Wright State University

Dennis Terry, Temple University

Jessica Tierney, University of Arizona

Aradhna Tripati, University of California Los Angeles

Michael Tuite, NASA Jet Propulsion Laboratory

Susana Velasquez-Franco, University of Utah

Josef Werne, University of Pittsburgh

Lisa White, University of California Berkeley

Debra Willard, United States Geological Survey

Jack Williams, University of Wisconsin Madison

Alexander Wolfe, University of Winnipeg

Chad Yost, Indiana State University

Fasong Yuan, Cleveland State University

James Zachos, University of California Santa Cruz

Susan Zimmerman, Lawrence Livermore National Laboratory

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