It really, really sounds like you haven’t done the math. The average per-capita CO2 emissions in the USA is about 15 tons (among the highest in the world) and a round-trip flight between SF and NY is about 1.5 tons, 10% of that. So if you flew to conferences 10 times per year, you would be using the entire carbon footprint of an average US citizen, which is among the highest in the world.
Your original statement - that a carbon-hedonistic lifestyle of frequent flying and cruise ships would still be lower CO2 output than having children - is flatly wrong, and your source does not bolster your argument.
Sure, but who's to say whether or not those children will fly on planes or go on cruises? Or their grandchildren? Or their great-grandchildren? This strikes me as a fallacious argument that simply not going on cruises or plane rides can offset the environmental footprint of having children. At least not unless there's some mechanism to forbid those children from every flying on a plane or taking a cruise - and not aware of any such mechanism.
