Technical Comments

Comment on “Long-term climate forcing by atmospheric oxygen concentrations”

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Science  08 Jul 2016:
Vol. 353, Issue 6295, pp. 132
DOI: 10.1126/science.aad6976


Poulsen et al. (Reports, 12 June 2015, p. 1238) argued that lower atmospheric oxygen levels during the Phanerozoic would have given a warmer climate. However, radiative and atmospheric structure changes under lower pressure both cause cooling, making their result unusual in that a hierarchy of models gives opposing results. Scrutiny of how radiative and cloud processes were represented, and a mechanistic explanation of the results, are required.

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