Katsumi Matsumoto
University of Minnesota
Date/Time: Friday 13th April, 15:30 – 16:30
Venue: IMAS Sandy Bay seminar room
Abstract:
Natural radiocarbon is produced in the atmosphere and distributed among the the three “active” reservoirs: the atmosphere, ocean, and terrestrial biosphere. The relative abundance of radiocarbon in these reservoirs largely reflects the kinetics of carbon cycle and climate state. For example, today’s oceanic abundance of radiocarbon is taken as a measure of deep water circulation and ventilation. During deglaciation, atmospheric radiocarbon abundance appears to have varied significantly in response to rapid climate change such as the Younger Dryas. Traditional view holds that during rapid climate change, the North Atlantic Deep Water was slowed, thus reducing the oceanic uptake of radiocarbon and leading to its accumulation in the atmosphere. In a new study using an earth system model of intermediate complexity, I argue that atmospheric radiocarbon should have in fact been reduced, as the reduction of the Atlantic meridional circulation was compensated by enhanced ventilation in the southern hemisphere.