The temperature–CO2 climate connection: an epistemological reappraisal of ice-core messages
- Institut de Physique du Globe de Paris, 1 Rue Jussieu, 75005 Paris, France
Abstract. As simply based on fundamental logic and on the concepts of cause and effect, an epistemological examination of the geochemical analyses performed on the Vostok ice cores invalidates the marked greenhouse effect on past climate usually assigned to CO2 and CH4. In agreement with the determining role assigned to Milankovitch cycles, temperature has, instead, constantly remained the long-term controlling parameter during the past 423 kyr, which, in turn, determined both CO2 and CH4 concentrations, whose variations exerted, at most, a minor feedback on temperature itself. If not refuted, the demonstration indicates that the greenhouse effect of CO2 on 20th century and today's climate remains to be documented, as already concluded from other evidence. The epistemological weakness of current simulations originates from the fact that they do not rely on any independent evidence for the influence of greenhouse gases on climate over long enough periods of time. The validity of models will, in particular, not be demonstrated as long as at least the most important features of climate changes, namely the glacial–interglacial transitions and the differing durations of interglacial periods, remain unaccounted for. Similarly, the constant 7 kyr time lag between temperature and CO2 decreases following deglaciation is another important feature that needs to be understood. Considered in this light, the current climate debate should be considered as being the latest of the great controversies that have punctuated the march of the Earth sciences, although its markedly differs from the preceding ones by its most varied social, environmental, economical and political ramifications.
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It has been brought to our attention that the article 'The temperature–CO2 climate connection: an epistemological reappraisal of ice-core messages' by Pascal Richet (Hist. Geo Space. Sci., 12, 97–110, 2021) may not have met the standard of fair and impartial peer review, concerns that we take very seriously. Any decision we take regarding this article is motivated purely by our commitment to publication ethics and scientific discourse. In the interest of transparency, we summarize relevant aspects of the case in the Copernicus statement on the review process of manuscript HGSS-2021-1.
In the light of the aspects mentioned in our statement and after conferring with the author, the HGSS editorial board, and experts in the field, Copernicus Publications has come to the decision to temporarily bar access to the article and perform a post-publication review, as recommended by COPE in such cases. Reports and the outcome of this review will be published, and the article will be handled accordingly. Regardless of the outcome, Copernicus Publications will carefully review the editorial practices and peer-review process of HGSS.