We propose to study examples of past climate warming and environmental change in order to find the main patterns of ocean feedbacks on climate by concentrating on changes in three-dimensional (3D) ocean circulation, ocean carbon cycle, gas hydrate dynamics, and the influence of geological greenhouse gas emissions. The examples range from the extreme global warming during the Paleocene Eocene Thermal Maximum (PET M, 55 Ma), to the glacial/interglacial transitions, the Holocene climate optimum to the regionally confined medieval warm period. We shall integrate high performance Earth system modelling with geophysical fieldwork on modern analogues of gas release and high-resolution sedimentological and paleoceanographic proxy work to provide a synthesis of the relevant ocean processes during periods of climate warming.
This research topic aims to answer the following specific questions. How did the 3D ocean circulation control warming, how did it respond to different forcing factors, and what was the climate feedback? How does the ocean carbon cycle response to climate warming operate under different background conditions? How important were geological carbon emissions including gas hydrate dissociation in
driving environmental change during the PETM?
Focus 1: Climate model simulations focusing on the different warming episodes will take into account variable distributions of the continents, orbital parameters, ice sheets and greenhouse gas levels.
Focus 2: In order to reconstruct past changes in marine environmental conditions and climate, centennial-scale records will be established across the different warming epochs (δ18O, δ13C, Mg/Ca, etc.).
Focus 3: We will investigate geological forcing mechanisms of climate warming.