Articles | Volume 13, issue 10
Clim. Past, 13, 1355–1379, 2017
Clim. Past, 13, 1355–1379, 2017
Research article
13 Oct 2017
Research article | 13 Oct 2017

Climatic history of the northeastern United States during the past 3000 years

Jennifer R. Marlon1, Neil Pederson2, Connor Nolan3, Simon Goring4, Bryan Shuman5, Ann Robertson1, Robert Booth6, Patrick J. Bartlein7, Melissa A. Berke8, Michael Clifford9, Edward Cook10, Ann Dieffenbacher-Krall11, Michael C. Dietze12, Amy Hessl13, J. Bradford Hubeny14, Stephen T. Jackson3,15, Jeremiah Marsicek5, Jason McLachlan16, Cary J. Mock17, David J. P. Moore18, Jonathan Nichols19, Dorothy Peteet19, Kevin Schaefer20, Valerie Trouet21, Charles Umbanhowar22, John W. Williams4, and Zicheng Yu6 Jennifer R. Marlon et al.
  • 1Yale School of Forestry and Environmental Studies, New Haven, CT 06511, USA
  • 2Harvard Forest, Harvard University, Petersham, MA 01366, USA
  • 3Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA
  • 4Department of Geography, Center for Climatic Research, University of Wisconsin-Madison, Madison, WI 53706, USA
  • 5Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071, USA
  • 6Earth and Environmental Science Department, Lehigh University, Bethlehem, PA 18015, USA
  • 7Department of Geography, University of Oregon, Eugene, OR 97403, USA
  • 8Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
  • 9Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, NV 89119, USA
  • 10Tree-Ring Laboratory, Lamont-Doherty Earth Observatory, Palisades, NY 10964, USA
  • 11School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
  • 12Department of Earth and Environment, Boston University, Boston, MA 02215, USA
  • 13Department of Geology and Geography, West Virginia University, Morgantown, WV 26501, USA
  • 14Department of Geological Sciences, Salem State University, Salem, MA 01970, USA
  • 15Southwest Climate Science Center, US Geological Survey, Tucson, AZ 85719, USA
  • 16Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
  • 17Department of Geography, University of South Carolina, Columbia, SC 29208, USA
  • 18Department of Geosciences and School of Natural Resources and Environment, University of Arizona, Tucson, AZ 85721, USA
  • 19Biology and Paleo Environment, Lamont-Doherty Earth Observatory, Palisades, NY 10964, USA
  • 20National Snow and Ice Data Center, University of Colorado, Boulder, CO 80309, USA
  • 21Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA
  • 22Departments of Biology and Environmental Studies, St. Olaf College, Northfield, MN 55057, USA

Abstract. Many ecosystem processes that influence Earth system feedbacks – vegetation growth, water and nutrient cycling, disturbance regimes – are strongly influenced by multidecadal- to millennial-scale climate variations that cannot be directly observed. Paleoclimate records provide information about these variations, forming the basis of our understanding and modeling of them. Fossil pollen records are abundant in the NE US, but cannot simultaneously provide information about paleoclimate and past vegetation in a modeling context because this leads to circular logic. If pollen data are used to constrain past vegetation changes, then the remaining paleoclimate archives in the northeastern US (NE US) are quite limited. Nonetheless, a growing number of diverse reconstructions have been developed but have not yet been examined together. Here we conduct a systematic review, assessment, and comparison of paleotemperature and paleohydrological proxies from the NE US for the last 3000 years. Regional temperature reconstructions (primarily summer) show a long-term cooling trend (1000 BCE–1700 CE) consistent with hemispheric-scale reconstructions, while hydroclimate data show gradually wetter conditions through the present day. Multiple proxies suggest that a prolonged, widespread drought occurred between 550 and 750 CE. Dry conditions are also evident during the Medieval Climate Anomaly, which was warmer and drier than the Little Ice Age and drier than today. There is some evidence for an acceleration of the longer-term wetting trend in the NE US during the past century; coupled with an abrupt shift from decreasing to increasing temperatures in the past century, these changes could have wide-ranging implications for species distributions, ecosystem dynamics, and extreme weather events. More work is needed to gather paleoclimate data in the NE US to make inter-proxy comparisons and to improve estimates of uncertainty in reconstructions.

Short summary
To improve our understanding of paleoclimate in the northeastern (NE) US, we compiled data from pollen, tree rings, lake levels, testate amoeba from bogs, and other proxies from the last 3000 years. The paleoclimate synthesis supports long-term cooling until the 1800s and reveals an abrupt transition from wet to dry conditions around 550–750  CE. Evidence suggests the region is now becoming warmer and wetter, but more calibrated data are needed, especially to capture multidecadal variability.