Surface temperatures over geological time

Analyses of phylogenetic trees of prokaryotic and eukaryotic phototrophs, organisms that use light for metabolic processes, and the thermostabilities of the species’ ancient nucleoside diphosphate kinase enzymes, which are indicative of growing conditions, suggest that temperatures of Earth’s surface environment decreased from approximately 75°C in the Archean to approximately 35°C in the Devonian, consistent with previous isotopic and protein temperature reconstructions. - Read at PNAS

Article #17-02729: “Reconstructed ancestral enzymes suggest long-term cooling of Earth’s photic zone since the Archean,” by Amanda Garcia, J. William Schopf, Shin-ichi Yokobori, Satoshi Akanuma, and Akihiko Yamagishi.