A fully coupled ocean‐atmosphere general circulation model (the Fast Ocean‐Atmosphere Model) is used to simulate the Neoproterozoic climate with a reduced solar luminosity (95% of present‐day), low atmospheric CO 2 (140 ppmv), and an idealized tropical supercontinent. Two coupled simulations were completed with present‐day and cold initial ocean temperatures. These experiments are compared with uncoupled (i.e., mixed‐layer) model experiments to determine the impact of a dynamical ocean on the Neoproterozoic simulations. In contrast to global sea‐ice coverage in the uncoupled experiments, the sea‐ice margin seasonally advances to 46 and 55° latitude in the coupled experiments. The coupled simulations demonstrate that dynamic ocean processes can prevent a snowball solution and suggest that a reduced solar luminosity and low atmospheric CO 2 are not by themselves sufficient conditions for a snowball solution. Heat exchange through vertical mixing in the mid‐latitudes, caused by static instability, is identified as the primary process halting the advance of the sea‐ice margin.
No takes yet. Share an insight, caveat, or question.
Poulsen et al. (2001) studied this question.