Resultados de modelo UVic Ultima Deglaciacion - UVic model output Last Deglaciation V2

Abstract

The early last deglaciation (20-15 ka) is characterized by sea level and atmospheric CO2 increase. Changes in ocean circulation, temperature, and dust fluxes have been proposed to transfer carbon from the ocean to the atmosphere, but quantification of these mechanisms is complicated by rapid dynamics and uncertainties of forcings and feedbacks. However, high time resolution tracers may capture some aspects of the processes involved. Here we analyze a global compilation of stable carbon isotope ratios (13C/12C) from benthic foraminifera, which shows enrichment in deep waters of Antarctic origin and depletion in upper North Atlantic Deep Waters during Heinrich Stadial 1. A global climate model is used to attribute effects of three hypothesized forcings: North Atlantic fresh water fluxes, increased Southern Ocean (SO) ventilation, and decreasing atmospheric iron fluxes and export production. We find that SO processes propagate an increase in 13C/12C of dissolved inorganic carbon (DIC) to Antarctic-originated deep waters, in agreement with reconstructions. Conversely, effects of Atlantic Meridional Overturning Circulation (AMOC) changes are small. Our simulations are able to explain early deglacial atmospheric CO2 rise, supporting the importance of SO ventilation and export production to set glacial-interglacial changes in the carbon cycle.