Carbon’s role in atmosphere formation

[knocker]

A new study in Proceedings of the National Academy of Sciences suggests that the way carbon moves from within a planet to the surface plays a big role in the evolution of a planet's atmosphere. Mars, which likely released much of its carbon as methane, might have been warm enough to support liquid water.

http://news.brown.edu/pressreleases/2013/04/magma

[frogesque]

It's not so much whether methane could warm Mars, more that a sufficient atmospheric pressure and temperature could develop to keep surface water at a liquid phase. Simple warming alone would just evaporate (more accurately: sublime) any locked up permafrost.

It's becoming fairly clear that Mars did have a heavy atmosphere and a warmer temperature at some stage(s) that did allow surface water. Not so sure that it could return to those days with the resources available.