High resolution alkenone palaeobarometry indicates relatively stable pCO2 during the Pliocene (3.3 to 2.8 Ma)

Marcus P S Badger, Daniela N Schmidt, A Mackensen, Rich D Pancost

Research output: Contribution to journalArticle (Academic Journal)peer-review

55 Citations (Scopus)
387 Downloads (Pure)

Abstract

Temperature reconstructions indicate that the Pliocene was ~ 3 °C warmer globally than today, and several recent reconstructions of Pliocene atmospheric CO2 indicate that it was above pre-industrial levels and similar to those likely to be seen this century. However, many of these reconstructions have been of relatively low temporal resolution, meaning that these records may have failed to capture variations associated with the 41 Kyr glacial-interglacial cycles thought to operate in the Pliocene. Here we present a new, high temporal resolution alkenone carbon isotope based record of pCO2 spanning 2.8 to 3.3 million years ago from ODP Site 999. Our record is of high enough resolution (~19 Kyrs) to resolve glacial-interglacial changes beyond the intrinsic uncertainty of the proxy method. The record suggests that Pliocene CO2 levels were relatively stable, exhibiting variation less than 55 ppm. We perform sensitivity studies to investigate the possible effect of changing sea surface temperature, which highlights the importance of accurate and precise SST reconstructions for alkenone palaeobarometry, but demonstrate that these uncertainties do not affect our conclusions of relatively stable pCO2 levels during this interval.

Original languageEnglish
Article number20130094
Pages (from-to)20130094
Number of pages16
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume371
Issue number2001
Early online date16 Sep 2013
DOIs
Publication statusPublished - 28 Oct 2013

Keywords

  • Pliocene
  • pCO(2)
  • atmospheric carbon dioxide
  • climate
  • alkenone
  • Ocean Drilling Program Site 999
  • CARBON ISOTOPIC FRACTIONATION
  • SEA-SURFACE TEMPERATURES
  • VOSTOK ICE CORE
  • GROWTH-RATE
  • DIOXIDE CONCENTRATION
  • CO2 CONCENTRATION
  • ATMOSPHERIC CO2
  • PHYTOPLANKTON
  • CALIBRATION
  • CALCITE

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