Unfortunately...

CO2 flows have not been imaged on Mars, nor will they be, at least not the kind that the "White Mars" hypothesis envisions. But that's all right.

The problem for "anti-wet" Mars folks is that there is an absolute abundance of near-surface water (which could be ice, liquid or chemically bonded) that must be recharged from deep reservoirs. Those reservoirs are almost certainly liquid, and probably very extensive.

From time to time, liquid water has been discharged directly to the surface from the interior, causing most of the extended channelling and catastrophic chaos we see on the surface today.

Rainfall has historically occurred on the surface and snowfall occurs to this day. There is nothing to prevent liquid water temporarily at the surface, either now or in the past. In some places, liquid water may persist at the surface for hours every day; it can persist under an ice cover for quite a long time, indefinitely so long as there is some means of recharge.

Impact has of course affected surface conditions. However, many circular formations on the surface have been misidentified. When the actual cratering history of Mars is better known, the implications and consequences of these impacts may begin to be better understood. But right now, the misidentification of so many circular formations as impact structures interferes with reasonable understanding. Venus and Io provide some alternative circular formations (internally generated) for consideration (and both provide a startling lack of impact structures).

Eventually, the static model of Mars will give over to a more or less nuanced understanding of a dynamic Mars. We've been in the throes of a paradigm shift for a decade or more... given some more time, and our understanding of the Red Planet (no longer butterscotch! yay!) will be so changed that today's beliefs will seem naive and quaint if not altogether obtuse.

Baby steps. Baby steps.

Cheers, BRFelix