Thursday, May 23, 2013

New paper finds another non-hockey-stick in Peru

Climate activist Lonnie Thompson has finally published his paper today on ice core data from the Quelccaya ice cap in Peru, data that Steve McIntyre requested to be archived for years. Plotting the variance-adjusted online data shows a non-hockey-stick from 1900-2009, with temperatures during the 1930's exceeding those of the 21st century and end of the record in 2009.
Relative temperature proxy on vertical axis, year on horizontal axis

Vol. 340 no. 6135 pp. 945-950 
DOI: 10.1126/science.1234210

Annually Resolved Ice Core Records of Tropical Climate Variability over the Past ~1800 Years

  1. P.-N. Lin1
+Author Affiliations
  1. 1Byrd Polar Research Center, The Ohio State University, Columbus, OH 43210, USA.
  2. 2School of Earth Sciences, The Ohio State University, Columbus, OH 43210, USA.
  3. 3Department of Geography, The Ohio State University, Columbus, OH 43210, USA.
  4. 4Institute of Geography, Russian Academy of Sciences, Moscow, Russia.
  1. *Corresponding author. E-mail:
Ice cores from low latitudes can provide a wealth of unique information about past climate in the tropics, but they are difficult to recover and few exist. Here, we report annually resolved ice core records from the Quelccaya ice cap (5670 meters above sea level) in Peru that extend back ~1800 years and provide a high-resolution record of climate variability there. Oxygen isotopic ratios (δ18O) are linked to sea surface temperatures in the tropical eastern Pacific, whereas concentrations of ammonium and nitrate document the dominant role played by the migration of the Intertropical Convergence Zone in the region of the tropical Andes. Quelccaya continues to retreat and thin. Radiocarbon dates on wetland plants exposed along its retreating margins indicate that it has not been smaller for at least six millennia.

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