Phanerozoic paleotemperatures: The earth’s changing climate during the last 540 million years

This study provides a comprehensive and quantitative estimate of how global temperatures have changed during the last 540 million years. It combines paleotemperature measurements determined from oxygen isotopes with broader insights obtained changing distribution lithologic indicators climate, such as coals, evaporites , calcretes reefs, bauxite deposits. The waxing waning Earth’s great polar icecaps been mapped using past tillites, dropstones, glendonites. temperature model presented here includes estimates average temperate (GAT), tropical (∆T° tropical), deep ocean temperatures, temperatures. Though similar, in many respects, to history deduced directly isotopes, our does not predict extreme high for Early Paleozoic required by isotopic investigations. changes Phanerozoic has summarized “paleotemperature timescale” that subdivides climatic events into 8 major climate modes; each mode is made up 3-4 pairs warming cooling episodes (chronotemps). A detailed narrative describes these affected geological processes eruption Large Igneous Provinces (LIPS) (warming) bolide impacts (cooling). allows deeper understanding interconnected geologic, tectonic, paleoclimatic, paleoceanographic, evolutionary shaped planet, we make explicit predictions about can be tested evaluated. By quantitatively describing pattern change through time, may able gain important Earth System fundamental causes on timescales. These help us better understand problems challenges face result Future Global Warming.