Personally, I would not go so far as to interpret one paper that addresses (and counters) some aspects of White Mars as evidence that "Nick is making people worried." In fact, one useful measure is to examine how many workers actually address White Mars, or even reference Nick's work. The number, most assuredly is increasing, but based on my careful perusal of the planetary science literature, I would hardly conclude that scientists are "worried." Frankly, and to put it charitably, the vast majority of the Mars science community does not find Nick's CO2-based hypotheses plausible. To put it not so charitably, some have actually characterized White Mars, though mostly in private, as "fringe" or "crankish."

For me, I believe that it too harsh. Though I do not find White Mars persuasive, some of the work Nick has been involved in recently, especially relating to his original ideas about features at Sisyphi Cavi, Mars (which have been accepted for publication in a peer-reviewed journal), is interesting. Though I still remain on the H2O side of the fence, I will admit, as I have always done, that the "CO2 faction" and their efforts have been a great service to Mars science. By pointing out flaws (some of them glaring) in existing H2O models, they have forced the H2O adherents to defend their positions with data, hard numbers, and logic - not by simple hand waving. Both sides have extremists (or evangelists), and both sides have gaping holes in their models, but as you allude to, the sharpened debate will, in all likelihood, converge on the final answer(s). Hopefully, these "answers" will lead to newer, more provocative questions. This is how True Science *should* work.

Alex R. Blackwell
University of Hawaii