Snowball prevention questioned.

ABSTRACT

The 'snowball Earth' hypothesis interprets geological evidence as indicating multi-million-year episodes of global glaciation near the beginning and end of the Proterozoic eon. On the basis of a coupled carbon cycle-climate model, Peltier et al. propose that temperature-dependent remineralization of organic carbon in a Neoproterozoic ocean with 100-1,000x more dissolved organic carbon than today could create a negative climate feedback, thereby preventing a snowball Earth. Their results are sensitive to initial conditions and model parameters; moreover, important geological observations and components of the carbon cycle are not considered-notably the absence of sources or sinks of carbon. Their model results fall short of explaining the geological evidence in the absence of global glaciation.