at least until next year.

"There is no support for the "White Mars" hypothesis -- at least none with regard to the famous (albeit imaginary) Hoffman Flows of CO2."

Except for the fact that something has to account for the features observed on the surface of Mars, and water does not operate in such a way as to produce them...

"His conceptual breakthrough was not those flows, however. Instead, he demonstrated the likelihood that the surface of Mars has mostly always been cold, usually colder than it is today."

Hoffman's conceptual breakthrough was having enough guts to point out the obvious, which is that water does not behave in the way the watery Mars nuts have been spouting for over 100 years.

"That fundamental realization is changing most workers' understanding of Martian history, which in turn is affecting notions of Martian biology. If Mars has always been cold, and there was no early "clement" era, the question is: could Mars have developed native biology, and how could there be Martian biology today? "

Actually, very few people care intensely whether there's life on Mars now or ever...

Mars has cooled, has little magnetic field, and thus next to no shieleing from radiation. My guess, and this is merely a guess right now, is that the C14 load resulting from the radiation is enough to make life almost impossible - the neutrons from C14 decay will split the DNA.

"Despite the "Cold Mars" model, however, there are signs all over the planet of massive volcanism and volcanic resurfacing, some of it very recent. Now you can't have that kind of volcanic activity on the surface without a hot interior. Despite the lack of indisputable evidence that Mars is currently volcanically active, signs of recent volcanism are too strong to dismiss."

There's a big difference between "pyroclastic" mud and lava - and much of the resurfacing is easliy demonstated to be "pyroclastic" mud by examing the results of impacts on it. "Pyroclastic" muds of this type can be produced by simple gravitational compression of clathrates - no need for help from Mars' pitiful molten core.

This is not to say that there is no volcanism on Mars. It is problably related to massive impact, as it is on Dione...

"So. We may find that a cold surface has been affected -- throughout the planet's history -- by an active interior (which may have provided periodic "clement" conditions in some regions some of the time, and that would have very interesting implications for biology.)

The key events affecting martian biology would have been cometary impacts every 26 million years or so - and you can see the strata that resulted from them on many areas of Mars. These impacts could have provided some both radiation shielding and conditions more favorable to life - but in more recent times the C14 load would have intervened...

"But there were no CO2 flows. Ever."

Too late - CO2 flows have already been imaged, and if imaging continues, more of them will be seen...

Cheers, BRFelix