PMIP Ocean - Understanding changes since the Last Glacial Maximum

C data indicate that the Atlantic Meridional Overturning Circulation (AMOC) during the LGM may not have been significantly different from today. Another presentation highlighted that in model simulations of the LGM, ocean circulation requires thousands of years to equilibrate. This raised the issue of whether the LGM (or in fact any time interval) can be considered to ever be in an equilibrium state, either for models or data reconstructions. Although radiocarbon is perhaps the most direct proxy for deep ocean circulation, independent dating is needed to allow its interpretation as a circulation tracer. The assumption of constant surface reservoir ages made in many previous studies may in some cases not be true, at least during the deglaciation. Nevertheless, new radiocarbon data from the North pand Southern Ocean advance our understanding of deep ocean circulation changes during the LGM and deglacial intervals.