Researchers look to the Southern Ocean for an explanation of the 'Last Glacial Maximum'

June 2, 2014 by Genevieve Wanucha in Earth / Earth Sciences
An artist's rendering of ice age Earth at glacial maximum. Credit: Ittiz/Wikimedia Commons






Lung of the ocean



But during the LGM, permanent covered much more of the Southern Ocean's surface. Ferrari and colleagues decided to explore how that extended sea ice would have affected the Southern Ocean's ability to exchange CO2 with the atmosphere.

Shock to the system




Dependent relationship

The study suggests a dynamic link between sea-ice expansion and the increase of water insulated from the atmosphere, which the field has long treated as independent events. This insight takes on extra relevance in light of the fact that paleoclimatologists need to explain not just the very low levels of atmospheric CO2 during the last , but also the fact that this happened during each of the last four glacial periods, as the paleoclimate record reveals.


"This study is an elegant, straightforward explanation that pulls all these pieces together into one place like no one has managed to do before," says Daniel Sigman, a professor of geological and geophysical sciences at Princeton, who was not involved in the study.
Sigman, who tries to understand carbon fluxes in the last ice age, says that this new framework narrows his focus to a smaller range of possibilities. "What it really does is tune me in to the sea ice and biochemical conditions that I need to see at the Southern Ocean's surface for the full CO2 drop to be realized."

More information: "Antarctic sea ice control on ocean circulation in present and glacial climates," by Raffaele Ferrari et al. www.pnas.org/cgi/doi/10.1073/pnas.1323922111

Provided by Massachusetts Institute of Technology

"Researchers look to the Southern Ocean for an explanation of the 'Last Glacial Maximum'" June 2, 2014 http://phys.org/news/2014-06-southern-ocean-explanation-glacial-maximum.html