Recent advances on the dynamical representation and our understanding of the last interglacial climate
Séminaire d’E. Capron (BAS, CIC), Mardi 4 Septembre à 10h30 en salle Lliboutry, Bât. Glaciologie
RECONSTITUTION SPATIO-TEMPORELLE ET COMPRÉHENSION DU CLIMAT CHAUD DU DERNIER INTERGLACIAIRE – UN POINT SUR LES AVANCÉES RÉCENTES
(RECENT ADVANCES ON THE DYNAMICAL REPRESENTATION AND OUR UNDERSTANDING OF THE LAST INTERGLACIAL CLIMATE)
British Antarctic Survey (UK) ; Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen (DK).
The last interglacial period ( 129-116 kyr ago) was characterized by warmer-than-today High Latitudes and higher global sea level. It represents an interesting case study to gain insights into climate processes and feedbacks under a range of regional temperature changes comparable to those projected by the end of 2100.
In this talk, I will highlight recent insights on the Last Interglacial climate based on the combination of temperature reconstructions from ice and marine archives with new model outputs. I will present a high latitude temperature data synthesis based on coherent chronologies between paleoclimatic records. This compilation provides the first robust evidence for asynchronous surface temperature evolutions across the globe at the Last Interglacial onset. It also allows to identify important missing processes in state-of-the-art model climate simulations to reproduce correctly the Last Interglacial climate evolution.
In particular and based on new model experiments, I will show that a freshwater input into the North Atlantic (due to the Northern Hemisphere ice sheet early melting) needs to be accounted for in addition to the orbital and greenhouse gas concentration forcing in climate simulations, to explain the evolution of the early Last Interglacial climate.
I will finally present our latest results that provide appropriate Last Interglacial data benchmark and a new transient modeling framework over the preceding deglaciation as part of Phase 4 of the international Paleoclimate Model Intercomparison Project (PMIP4).
Overall our work illustrates how using a data-model approach enables to progress on our understanding of the Last Interglacial climate. Such integrative approach should be extended to older interglacial periods as they also hold lessons about the impacts of a range of warm conditions on the different components of the Earth System (i.e. polar ice sheets, ocean circulation) and provide additional test cases for climate models outside their calibration range.