MdM SEMINAR SERIES - "Surprising new insights on the Southern Ocean carbon sink from the SOCCOM project" by Jorge Sarmiento

MdM SEMINAR SERIES

Title: “Surprising new insights on the Southern Ocean carbon sink from the SOCCOM project"

Speaker: Jorge Sarmiento, Princeton University

Date: Monday, 19^th March 2018

Time: 12h

Venue: Z/022- Z/023

Abstract

Humans are rapidly emitting carbon dioxide to the atmosphere. Some of that carbon dioxide stays in the atmosphere, causing climate change, while the remainder is taken up by ‘carbon sinks’ in the ocean and on land. Substantial uncertainty remains in how much these natural carbon sinks will mitigate future climate change, which affects our ability to meet temperature-defined climate targets such as the Paris Accord. The Southern Ocean is recognized as a critical player in the ocean carbon sink, but has been very difficult to observe and therefore has very large uncertainties. A new set of year-round robotic measurements made through the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Program indicate a major, previously unobserved flux of CO2 from the ocean to the atmosphere in the region between the Subantarctic Front and the southern boundry of the Antarctic Circompolar Current, which is characterized by strong upwelling. The overall impact of this CO2 flux, and other smaller adjustments resulting from the new float observations, is to modify the entire Southern Ocean south of 35°S from an estimated carbon sink of -0.6 Pg C/yr, to a carbon source of 0.1 Pg C/yr. This implies an overall previously undetected source of 0.7 Pg C/yr, which could be a result of interannual variability or of inadequate data coverage in the climatic average. I will discuss the implications of such a Southern Ocean source of CO2 for our current understanding of interannual variability and the spatial distribution of carbon sources and sinks in the ocean as well as on land.

Bio

¿Dr. Jorge L. Sarmiento is the George J. Magee Professor of Geoscience and Geological Engineering, Professor of Geosciences at Princeton University.  He obtained his PhD at the Lamont-Doherty Geological Observatory of Columbia University in 1978, and then served as a post-doc at the Geophysical Fluid Dynamics Laboratory/NOAA in Princeton before joining the Princeton University faculty in 1980.   He has published widely on the oceanic cycles of climatically important chemicals such as carbon dioxide, on the use of chemical tracers to study ocean circulation, and on the impact of climate change on ocean biogeochemistry.   He has participated in the scientific planning and execution of many of the large-scale multi-institutional and international oceanographic biogeochemical and tracer programs of the last two decades.   He was Director of Princeton's Atmospheric and Oceanic Sciences Program from 1980 to 1990 and 2006 to the present, and is Director of the Cooperative Institute for Climate Science.   He has served on the editorial board of multiple journals and as editor of Global Biogeochemical Cycles. He is a Fellow of the American Geophysical Union and the American Association for the Advancement of Science.