On stabilizing feedbacks in the long-term carbon cycle and other issue

Abstract:

Feedbacks controlling long-term fluxes in the carbon cycle and atmospheric CO2 are fundamental to stabilizing Earth's climate over multi-million year time scales. Based on available data, a strong case can be made that atmospheric CO2 concentrations over millions of years are controlled by a CO2-driven weathering feedback that maintains a mass balance between the CO2 input to the atmosphere from volcanism, metamorphism and net organic matter oxidation, and its removal by silicate rock weathering and subsequent carbonate mineral burial. This presentation will discuss issues such as the fine mass balance of long-term carbon fluxes that can be derived from reconstructions of atmospheric CO2 and ocean chemistry records. In addition, I will comment on alternative stabilizing feedbacks in the carbon cycle, including the potential role of organic carbon in driving greenhouse gas changes throughout Earth's history. Finally, if time permits, I will point out a few other stunning prerequisites necessary to maintain Earth habitability over billions of years.