The primary means by which the Earth maintains a habitable climate is the withdrawal of CO2 through continental weathering, and its deposition as carbonate and organic carbon. However, we know very little about the processes that control weathering (and therefore long-term climate), or the rates at which they interact with climate. Hence, we do not really understand why the Earth has been inhabitable for almost 85% of its existence.
Until recently, it has been hard to examine these interactions, because there have been no unambiguous tracers of palaeo-weathering processes. This project will use lithium isotopes, a relatively new proxy of continental weathering, and examine oceanic and continental records spanning rapid climate change events (e.g. warming events such as the PETM, or recent deglacials).
This will determine how rapidly the climate system uses weathering to recover from perturbations. In turn, this will give critical evidence on how the climate system operates, and how the Earth”s climate has maintained its remarkable stability for 4 billion years.