Continental drift, runoff, and weathering feedbacks: implications from climate model experiments

Changes in atmospheric carbon dioxide have been proposed as a major regulator of climate during the last 570 million years. Continental weathering and its variation over time are hypothesized to be important for controlling atmospheric carbon dioxide. Continental weathering is altered by changes in total runoff as well as changes in the size and elevation of the land masses to be weathered. When paleogeographic information for the Phanerozoic (570 m.y. ago to present) is used in a global climate model, the model exhibits substantial variations in precipitation, evaporation, and runoff. Even with dramatically different land-ocean distributions, an increase in global surface temperature leads to an increase in global precipitation but not always an increase in global runoff. The results imply that weathering feedback between temperature and runoff may be dependent on land-ocean configuration. -from Author