Title:
A global environmental crisis 42,000 years ago
Authors:
Alan Cooper, Chris S.M. Turney, Jonathan Palmer [et al]
Published:
Science, Volume 371, Issue 6531, pp. 811-818 (19 February 2021)
Abstract:
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.
See also:
Title:
Ancient trees show when the earth's magnetic field last flipped out
Author:
Nell Greenfieldboyce
Published:
WUWM, 18 February 2021