EGU21-6153, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A hotter-drought fingerprint on Earth’s forest mortality sites–warming accelerates risks

William M. Hammond1, A. Park Williams2, John T. Abatzoglou3, Henry D. Adams4, Tamir Klein5, Rosana López Rodríguez6, Cuauhtémoc Sáenz-Romero7, Henrik Hartmann8, David D. Breshears9, and Craig D. Allen10
William M. Hammond et al.
  • 1Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater OK, USA (
  • 2Lamont-Doherty Earth Observatory, Columbia University, Palisades NY, USA (
  • 3Management of Complex Systems, University of California, Merced CA, USA (
  • 4School of the Environment, Washington State University, Pullman WA, USA (
  • 5Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, IL (
  • 6Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, ES (
  • 7Instituto de Investigaciones sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia Michoacán, MX (
  • 8Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, DE (
  • 9School of Natural Resources and the Environment, University of Arizona, Tucson AZ, USA (
  • 10Department of Geography and Environmental Studies, University of New Mexico, Albuquerque NM, USA (

Earth’s forests face grave challenges in the Anthropocene, including hotter droughts increasingly associated with widespread forest die-off. But despite the vital importance of forests—especially historical forests—to global ecosystem services, their fates in a warming world remain highly uncertain. Critically missing is quantitative determination of hotter-drought climatic drivers at globally-distributed, ground-based, tree-mortality sites. We established a precisely geo-referenced global database documenting climate-induced mortality events spanning all tree-supporting biomes from 154 studies since 1970. Here we quantify a lethal global hotter-drought fingerprint from these tree-mortality sites across 675 locations encompassing 1,303 database plots. Frequency of these lethal climate conditions accelerates under projected warming, up 140% by +4℃. Our database, soon available at, provides initial footing for further community development of quantitative, ground-based monitoring of global tree mortality (e.g., still including peer-reviewed observations, but importantly also those from forestry professionals, land managers, and citizen scientists). Furthermore, our database immediately enables critical predictive model validation and improved remote sensing of mortality. While our initial database enabled empirical quantification of a global climate signal for hotter-drought triggered tree mortality, ongoing and online contributions to the database (with efforts to be more spatially representative) will enable myriad future analyses and progress toward understanding the role of hotter-drought in the mechanistically complex process of tree mortality. Our global fingerprint of lethal hotter-drought confirms many of Earth’s forests are increasingly imperiled by further warming.

How to cite: Hammond, W. M., Williams, A. P., Abatzoglou, J. T., Adams, H. D., Klein, T., Rodríguez, R. L., Sáenz-Romero, C., Hartmann, H., Breshears, D. D., and Allen, C. D.: A hotter-drought fingerprint on Earth’s forest mortality sites–warming accelerates risks, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6153,, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.