On the absence of solar evolution-driven warming through the Phanerozoic

Authors

  • David Waltham

    Corresponding author
    1. Department of Earth Sciences, Royal Holloway University of London, Egham Hill, Egham, Surrey, UK
    • Correspondence: David Waltham, Department of Earth Sciences, Royal Holloway University of London, Egham Hill, Egham, Surrey TW20 0EX, UK. Tel.: +44 1784 443617; e-mail: d.waltham@rhul.ac.uk

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Abstract

Reconstructed temperatures through the Phanerozoic indicate a gradual cooling or, at best, no significant temperature trend, despite a 4.4% increase in solar heating. It is possible that an underlying warming trend has simply been swamped by ‘noise’ due to significant data-errors and/or natural fluctuations. Alternatively, the lack of warming may indicate cooling by biological and/or geological processes, which happen to have the right amplitude to cancel the effects of solar warming. This paper demonstrates that the absence of Phanerozoic warming cannot be explained as a warming trend hidden by noise. It also shows that, given widely accepted estimates of climate sensitivity, it cannot be explained as cancellation by negative feedback in the climate system. The Gaia hypothesis, anthropic selection or some other unconventional mechanism may therefore have to be invoked to explain the absence of long-term warming through the Phanerozoic.

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