Migration of continental arcs dictates Earth's long-term climate state

Abstract

Earth has experienced multiple shifts between icehouse and greenhouse climate states over multimillion-year time scales, yet the dominant geological processes controlling these shifts remain uncertain. Continental arcs have been proposed to play a dual role in the global carbon cycle via volcanic and metamorphic degassing, as well as the chemical weathering of silicate rocks. Here we reconstructed the paleogeographic extent of active and extinct continental arcs to evaluate the global net degassing and weatherability over geological time. Our results show that prolonged glacial intervals are associated with shorter active continental arcs at mid-high latitudes and longer extinct continental arcs at low latitudes. Conversely, short-lived glacial intervals coincide with longer active continental arcs at mid-high latitudes and extinct continental arcs at low latitudes, or a reduction in the length of active continental arcs at mid-high latitudes combined with a moderate length of extinct continental arcs at low latitudes. We also observe that the length of active or extinct continental arcs at low latitudes increases during long-lived greenhouse intervals, potentially preventing a runaway greenhouse effect through increasing global weatherability. Our findings suggest that the importance of the development of continental arcs along latitudinal migration controlling Earth's climate state.