Tuesday, November 12, 2013

New paper finds ice core CO2 levels lag temperature by up to 5,000 years

A new paper published in Climate of the Past finds that CO2 levels lagged temperature changes in East Antarctic ice cores by 500-1500 years during the warming at the onset of the last interglacial, and lagged temperatures by 5,000 years after the start of glaciation at end of the last interglacial [~120,000 years ago].

Despite Al Gore's attempt to obscure this inconvenient truth, temperatures lead CO2 levels on long, intermediate, and short-term timescales, on both the upside and the downside. CO2 cannot be the 'control knob' or 'amplifier' of climate, because the tail does not wag the dogthe cause does not follow the effect, and the globe starts to warm and cool 500-5000 years in advance of CO2 changes.

Clim. Past, 9, 2507-2523, 2013

R. Schneider1,2, J. Schmitt1,2,3, P. Köhler3, F. Joos1,2, and H. Fischer1,2,3
1Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
2Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
3Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), P.O. Box 12 01 61, 27515 Bremerhaven, Germany

Abstract. The reconstruction of the stable carbon isotope evolution in atmospheric CO2 (δ13Catm), as archived in Antarctic ice cores, bears the potential to disentangle the contributions of the different carbon cycle fluxes causing past CO2 variations. Here we present a new record of δ13Catm before, during and after the Marine Isotope Stage 5.5 (155 000 to 105 000 yr BP). The dataset is archived on the data repository PANGEA® (www.pangea.de) under 10.1594/PANGAEA.817041. The record was derived with a well established sublimation method using ice from the EPICA Dome C (EDC) and the Talos Dome ice cores in East Antarctica. We find a 0.4‰ shift to heavier values between the mean δ13Catm level in the Penultimate (~ 140 000 yr BP) and Last Glacial Maximum (~ 22 000 yr BP), which can be explained by either (i) changes in the isotopic composition or (ii) intensity of the carbon input fluxes to the combined ocean/atmosphere carbon reservoir or (iii) by long-term peat buildup. Our isotopic data suggest that the carbon cycle evolution along Termination II and the subsequent interglacial was controlled by essentially the same processes as during the last 24 000 yr, but with different phasing and magnitudes. Furthermore, a 5000 yr lag in the CO2 decline relative to EDC [East Antarctic] temperatures is confirmed during the glacial inception at the end of MIS5.5 (120.000 [years ago]). Based on our isotopic data this lag can be explained by terrestrial carbon release and carbonate compensation.


  1. It all shows that the carbon cycle is far more complex than previously thought with multiple overlapping processes altering the speed of the cycle over long periods of time and moreover each shifting its significance relative to the others.

    The simplistic idea that our emissions have any significant effect overall is completely untenable.

    There are clearly natural spells when the atmospheric CO2 content increases or decreases over centuries at a time and the speed / scale of such changes is not adequately reflected in the ice core record.

    All we need next is a more complete analysis of the way different biological and geological processes affect the CO2 isotope balance so as to dispose of the flawed assumption that human emissions are driving recent changes in CO2 amounts.

    Stephen Wilde

    1. Thanks Stephen,

      I agree completely "The simplistic idea that our emissions have any significant effect overall is completely untenable."

      Knowledge of the global carbon cycle is in its infancy, but regardless, man's contribution makes little difference to the climate.