Early Eocene Climatic Optimum (EECO, ~53-51 million years) is one of the past warm periods, associated with high CO2 concentrations (~900-2500 ppmv), which can serve as an analogue for our possible future, high C02 climate. One notable feature of this hothouse climate state is the weaker meridional temperature gradient relative to pre-industrial values. This have been confirmed by both proxies and models, but the extent of the temperature gradient still requires more research. Models are challenged to reproduce the stronger than present day polar amplification signal, and it is also shown that high latitude proxy data are often influenced by seasonal bias. Thus, there is an uncertainty regarding both the observed and modelled meridional gradient and the mentioned issues complicate also the comparison between modeled and proxy data.
The project C1 investigates the meridional temperature gradient in the paleoclimate system through understanding of the energy transport processes, polar amplification in an ice-free world and seasonality. Methodologically, this project relys on modelling the EECO conditions with both high and low complexity models, designing sensitivity studies and comparing model and proxy data.