liquid water is hardly a step, confirmation, or support for Nick Hoffman's well-known "White Mars" hypothesis -- which is still a "liquid CO2" hypothesis, to the near complete exclusion of liquid water throughout almost all of Martian history.
The "Iceball Mars?" article referenced does not appear to support Nick Hoffman's "White Mars" hypothesis in any way, grudging or otherwise, unless "White Mars" only refers to color, or he has transformed it into an H2O rather than CO2 active volatile hypothesis.
In fact, the article supports the insights of some enthusiasts and amateurs, together with some Viking era professionals, who have long suggested that many of the enigmatic features on the Martian surface (especially in the Northern Lowlands) are the result of water ice mediation, a surface that may well have once been entirely covered with an "ocean" that would have been frozen solid at the surface. There could well have been liquid water below the ice cover, but there wouldn't have to be.
Nick's argument has come close to claiming that liquid water is IMPOSSIBLE under any circumstances anywhere on Mars, and at any time except in the far distant past, and then only as a result of temporary atmospheric density increase and surface warming due to impact. Grudgingly, Nick has allowed as how there could be reservoirs of liquid water perhaps 10 kilometers or more below the surface.
Nick's argument is that the only surface volatile worth considering is liquid CO2, explosively released. In this, Nick is almost certainly deep in error.
On the other hand, Nick has done something terribly important for the understanding of Mars -- something we can see hints of in the article referenced: he demonstrated better than anyone else has to date that Mars is not only cold now, it has almost ALWAYS BEEN COLDER THAN IT IS NOW.
In other words, there was probably never a "clement" Blue Mars era, and perhaps there can never be.
That does not mean that liquid CO2 has been the primary volatile modifying the Martian surface, but it doesn't mean it couldn't play a role.
From the article:
The notion that half of today’s dry, dusty
planet was recently covered by ice may
seem a bit far-fetched at first glance. But it
begins to look more plausible in the light of
new data on the extent of current polar ice.
hundreds of kilometers, according to
Odyssey data.
I would ask why a "recent" ice-cover would be considered "far-fetched" -- when the signs and evidence have suggested exactly that for a generation? What is it about the obvious that forces almost immediate dispute and/or rejection when it comes to Mars, The Planet of Deception? ;-)
Cheers, BRFelix