Climate response to orbital forcing during the Eocene deglaciated, high temperature, high CO2 state: New records from Sites 1210, 1258 & 1267

Lead Research Organisation: University of Southampton
Department Name: Sch of Ocean and Earth Science


In the past 150 years mankind has increased the level of atmospheric carbon dioxide in the atmosphere from 280 parts per million by volume (ppmv) to 380 ppmv. We know that this anthropogenic value is much higher than anything seen on Earth in the last 800 thousand years from the famous records of air bubbles trapped in layers of ice cored in Antarctica. At the rate at which China and India are industrializing, by the end of this century, the concentration of CO2 in the atmosphere is predicted to reach 750, perhaps 1000 ppmv. These sorts of concentrations have not been seen on Earth since the Eocene (about 50 million years ago) when our planet was much warmer and less glaciated than today (see cover story, New Scientist, 21 June, 2008). These remarkable observations mean that we must improve our understanding of the stability of these ancient geological climates. In the past this would not have been possible in the way that we propose because the sorts of geological materials required for this work (well-dated, well-preserved and undisturbed sediments from the depths of the oceans) were not available. However, the UK is part of a major international collaborative science program called the (Integrated)Ocean Drilling Program or (I)ODP. In its last phase of operation (I)ODP instigated a major campaign of drilling holes in the sea floor to retrieve the sorts of Eocene sediments required for this sort of work. Each of us was heavily involved in this campaign (see Part I, our 'track records'). Our proposal seeks funding to study natural climate variability during this 'Eocene greenhouse' interval using these recently recovered (I)ODP sediments. Specifically, we want to understand the sensitivity of climate to Earth's orbit of the Sun under this deglaciated, high temperature, high CO2 level state. We plan to generate palaeoclimate records for the surface and deep ocean by applying established chemical techniques to pin-head sized fossils called foraminifera that make their shells from calcium carbonate. A key aspect of our work will be to determine the rhythmic fluctuations in temperature and carbon cycle behaviour across different hemispheres, latitudes and oceans. Our work has the potential to identify novel methods to: 1) Tackle ongoing debate over the existence of substantial ice sheets during other intervals of geologic time. 2) Test for local (surface ocean export production) versus global (deep ocean 'acidity') control on the burial of CaCO3 at the sea floor.


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Description We document many short-term rapid warming events that took place around 50 million years ago when atmospheric greenhouse gas concentrations were high and Earth was much warmer than today. We interpret our records to indicate repeated, large-scale releases of dissolved organic carbon (at least 1,600 gigatonnes) from the ocean by ventilation (strengthened oxidation) of the ocean interior.
Exploitation Route To inform policy on human-driven climate change.
Sectors Environment

Description Integrated Ocean Drilling Program 
Organisation International Ocean Discovery Programme (IODP)
Country United States 
Sector Charity/Non Profit 
PI Contribution I co-lead IODP Expedition 342 and ODP Legs 199 & 207, three multi-million dollar multi-international collaboration as co-chief scientist and/or senior proponent. I participated in IODP Expedition 320. Members of my research group participated in these and many other (I)ODP expeditions
Collaborator Contribution see above and scientific papers arising
Impact many scientific publications. IODP is multi-international and multi-disciplinary