Eleni Anagnostou
Eleni Anagnostou is a biogeochemist and paleoceanographer at GEOMAR, where she leads a research group for projects focusing on carbon-climate dynamics in the Cenozoic. Her background is in Chemical Engineering (NTUA, Greece), continued by an MSc in Environmental Science (Rutgers, USA) and a PhD in Chemical Oceanography (DMCS, Rutgers, USA). She worked as a post doc at University of Southampton (UK) and Northeastern University/Claremont McKenna College (USA), followed by a year at ETH Zurich (Switzerland). Her group targets marine archives, such as foraminifera, corals and coralline algae, and we use trace elements and isotopes (e.g. boron) to reconstruct past climate variability from annual to million year time scales. Their main goal is to answer questions on the mechanisms driving the interaction between carbon, climate and sea level change during Earth’s history.
Resolving early Cenozoic carbon-climate relationships
Atmospheric carbon dioxide (CO2) plays an important part in determining climate on human and geological timescales. However, the link between climate and CO2 in Earth’s history is not always straightforward, particularly during periods of multiple climatic and environmental changes such as the early Cenozoic. Over the past years, our CO2 reconstructions using the boron isotope proxy (B-proxy) in planktonic foraminifera led to a series of advancements in our understanding and use of B-proxies, revealing the CO2 levels during the peak warm period of the Cenozoic, the early Eocene Climatic Optimum, and suggesting CO2 reduction as the main driver of Eocene cooling. Our additional reconstructions during the Eocene provided the ground to suggest the state dependency of climate sensitivity and potential mechanisms driving carbon and temperature variations during this Era. The analytical and methodological developments towards reducing reconstruction uncertainties for the B-proxies, now allow us to generate millennial-resolution CO2, as needed for targeting unique climate transitions and suspect tipping points in the climate system, such as the Eocene-Oligocene. Further, in a coordinated international effort through PAGES, we suggest an improved B-proxy CO2 curve for the Cenozoic, utilizing our refined understanding of the proxy and seawater and temperature constraints, which provides our evolving best estimates of CO2. These presented here, in addition to age model adjustments and new reconstructions all contribute to interrogate the relationship between Earth’s climate and CO2, and update our understanding of the interplay among variable forcings for long-term and short-term climate change.
