"... humans have certainly changed climate by interfering with it. But, nuclear weapons? I'm not sure I understand the mechanism of how it could warm the planet... I have sanity-checked things Elon Musk has said in the past and they do tend to be possible in theory... he has made money with Space X and Tesla."
Robert Walker, an inventor with degrees in math and philosophy, wrote on Science 2.0 with regard to Musk's Stephen Colbert interview.
"I found it surprising how seriously his rather off the cuff, and joking, remark has been taken by some reporters, reported as a major news story by many journalists."
MacDonald and Walker both seem to not take the idea of a plan to "nuke mars" seriously, so they probably wouldn't have gotten on national television with Stephen Colbertand made such statements. If they did, it would only be their professional reputation at stake, not billions invested in the stock market by shareholders. They have no fiduciary duty.
Art Bell and Leanord Nimoy could fairly be described as forward-thinking and thoroughly immersed in science fiction, if not outright science. They are and were celebrities and are and were responsible to no one. They have no fiduciary duty either.
Elon Musk, on the other hand, has a massive fiduciary duty. He certainly has a reputation of being a visionary, but MacDonald's statement that Musk has "made money with SpaceX and Tesla" is puzzling.
As SpaceX is a privately-held company, how MacDonald could state that Musk has "made money" with it, makes no sense. And the truth is, Musk has probably lost money on SpaceX. The SpaceX Falcon rocket, shown in the Stephen Colbert clip below, failed miserably.
Musk and a great many Tesla shareholders have made money, but the company has yet to regularly turn a profit. SolarCity Corporation (NASDAQ: SCTY), another Musk project, is bleeding money quickly and Seeking Alpha has asked if the GigaFab is turning into a "white elephant." If Tesla and SolarCity don't meet current, already greatly reduced, earnings expectations, after all the hype Musk has built around them, shares may not be able to hold onto their current rich valuations.
MacDonald and Walker are not widely-known scientists, but they are two of the only scientists who have made public statements, held up, even partially defending Musk's Stephen Colbert show Mars plans.
Listen to what Neil deGrasse Tyson, someone who appears to have knowledge of profits and losses, had to say to Business Insider in 2013.