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A millennial perspective on Arctic warming from 14C in quartz and plants emerging from beneath ice caps
Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado, Boulder, Colorado, USA
Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado, Boulder, Colorado, USA
Department of Geology, State University of New York at Buffalo, Buffalo, New York, USA
Geosciences Department, University of Arizona, Tucson, Arizona, USA
Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado, Boulder, Colorado, USA
Observational records show that the area of ice caps on northern Baffin Island, Arctic Canada has diminished by more than 50% since 1958. Fifty 14C dates on dead vegetation emerging beneath receding ice margins document the persistence of some of these ice caps since at least 350 AD. In situ cosmogenic 14C in rock surfaces, and 14C in plant macrofossils from lake-sediment cores demonstrate that the plateau remained ice-free through the middle Holocene, but has supported ice caps for more than 2000 of the past 2800 years. The rapid disappearance of these ice caps over the past century, despite decreasing summer insolation, further demonstrates the unusual character of 20th Century warmth. Widespread ice-cap expansion ∼1280 AD early in the Little Ice Age, and intensified expansion ∼1450 AD, coincide with peak stratospheric volcanic aerosol loading and reduced solar luminosity, suggesting that these mechanisms may have initiated ice-cap growth, subsequently maintained by strong positive feedbacks.
Received 17 September 2007; accepted 21 November 2007; published 11 January 2008.
Citation: (2008), A millennial perspective on Arctic warming from 14C in quartz and plants emerging from beneath ice caps, Geophys. Res. Lett., 35, L01502, doi:10.1029/2007GL032057.
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