A global environmental crisis 42,000 years ago

Research output: Contribution to journalArticle


Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.


  • Alan Cooper
  • Chris S.M. Turney
  • Jonathan Palmer
  • Alan Hogg
  • Matt McGlone
  • Janet Wilmshurst
  • Andrew M. Lorrey
  • Timothy J. Heaton
  • James M. Russell
  • Ken McCracken
  • Julien G. Anet
  • Eugene Rozanov
  • Marina Friedel
  • Ivo Suter
  • Thomas Peter
  • Anthony Dosseto
  • J. Tyler Faith
  • Pavla Fenwick
  • Christopher J. Fogwill
  • Konrad Hughen
  • Mathew Lipson
  • Jiabo Liu
  • Norbert Nowaczyk
  • Eleanor Rainsley
  • Christopher Bronk Ramsey
  • Paolo Sebastianelli
  • Yassine Souilmi
  • Janelle Stevenson
  • Zoë Thomas
  • Raymond Tobler
  • Roland Zech
External organisations
  • South Australian Museum
  • BlueSky Genetics
  • University of New South Wales
  • University of Waikato
  • Landcare Research
  • University of Auckland
  • National Institute of Water and Atmospheric Research, New Zealand
  • University of Sheffield
  • Brown University
  • Zurich University of Applied Sciences (ZHAW)
  • ETH Zürich
  • Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center (PMOD/WRC)
  • Saint Petersburg State University
  • Swiss Federal Laboratories for Materials Science and Technology
  • Alfred-Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven
  • University of Wollongong
  • Natural History Museum of Utah
  • Gondwana Tree-Ring Laboratory
  • Keele University
  • Woods Hole Oceanographic Institution
  • Southern University of Science and Technology
  • GFZ German Research Centre for Geosciences
  • University of Oxford
  • National University of Cordoba, Argentina
  • University of Adelaide
  • Australian National University
  • Friedrich Schiller University Jena
  • University of Utah
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Geology
Original languageEnglish
Pages (from-to)811-818
Number of pages8
Issue number6531
Publication statusPublished - 2021
Publication categoryResearch