'The role of palaeogeography in controlling Cretaceous and Paleogene climate'
Part of the School Seminar Series
Speaker: Professor Dan Lunt, University of Bristol
Host: Tom Dunkley-Jones
Although the current paradigm is that CO2 is the primary driver of large-scale Earth System change through the Cretaceous and Paleogene, the relative importance of changing palaeogeography on climate dynamics through this greenhouse period is yet to be fully explored. In particular, the opening and closing of key ocean gateways,
orogenesis, and continentality, could have a key role in determining not only the timing of key transitions (e.g. Eocene-Oligocene glaciation), but could also contribute directly to the large-scale trends. In addition, vegetation is likely to play a key role in mediating these climate changes.
Here, we present a new series of climate model simulations, built upon state-of-the-art palaeogeographic maps (~20 in total covering the Cretaceous and Paleogene). The suite of simulations allows us to consider key questions related to climate dynamics through this time period: (1) What is the role of changing palaeogeography (including gateways) in mediating ocean circulation, through changing gateways and continental configuration?
(2) What is the contribution of changing palaeogeography to climate, and climate sensitivity? (3) How do changing vegetation-climate interactions affect these issues?
Through considering the relationship between the local and regional scale, we explore the dangers of drawing global conclusions from local data, and highlight key areas where new palaeodata could be targeted to inform the above questions and better evaluate the models.