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Saturday, August 25, 2012

Recent Warming Reverses Long-Term Arctic Cooling, Science, 325 (2009)

ScienceVol. 325, No. 5945, pp. 1236-1239; doi10.1126/science.1173983

Recent Warming Reverses Long-Term Arctic Cooling

  1. 1School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA.
  2. 2Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80305, USA.
  3. 3Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA.
  4. 4Department of Geosciences, University of Massachusetts, Amherst, MA 01003, USA.
  5. 5Climatic Research Unit, University of East Anglia, Norwich NR4 7TJ, UK.
  6. 6Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA.
  7. 7Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
The temperature history of the first millennium C.E. is sparsely documented, especially in the Arctic. We present a synthesis of decadally resolved proxy temperature records from poleward of 60° N covering the past 2,000 years, which indicates that a pervasive cooling in progress 2,000 years ago continued through the Middle Ages and into the Little Ice Age. A 2,000-year transient climate simulation with the Community Climate System Model shows the same temperature sensitivity to changes in insolation as does our proxy reconstruction, supporting the inference that this long-term trend was caused by the steady orbitally driven reduction in summer insolation. The cooling trend was reversed during the 20th century, with four of the five warmest decades of our 2,000-year-long reconstruction occurring between 1950 and 2000.
Received for publication 24 March 2009. Accepted for publication 22 June 2009.
*Correspondence :

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