I completely agree - human nature being what it is, carbon reduction is simply not going to work fast enough. We either pretend humans are something they're not, or get to work designing tech to solve the problem. But there's a sharp divide among experts on the topic, with the two divisions named "engineers" and "druids". From a 2007 editorial

I suspect in the coming years the engineer/druid debate will become highly contentious, and a lot of shouting is going to happen. Hopefully we win.

I was listing all the end of the world scenarios and judging how useful a Mars colony would be to ensure the continuity of the human species. I wasn't comparing them.

As to asteroids: 90% of life wiped out, tsunamis and tech is destroyed, a dark day for mankind. But all of that is no better for people living on Mars - unless we are hypothesizing this Mars colony is sufficiently prosperous it can bring disaster relief. So long as some few thousand of us survive, our species continues and the Mars colony doesn't do us a lick of good. And at least a few thousand will certainly survive - the K-Pg extinction event was survived by many animals vastly less adaptable, resourceful, numerous and spread out than modern man. The only scenario were this isn't true and an asteroid is a real existential threat to humanity is a extremely *massive* impact. Something that liquefies the Earth's crust as the Theia impact is hypothesized to have done. In that case, yes having a Mars colony is essential to our species continuing.

Though all this talk of the Chicxulub event reminds me that I missed another end of the world scenario:

Mass volcanism. It's theorized the Toba volcano eruption reduced early man to a few thousand stragglers on the edge of Africa around 70000 BC. Although a similar event wouldn't doom modern man, something like the Permian Siberian Traps eruption probably would. However, the Traps eruption is theorized to have taken over a million years to happen - ample time to found Mars colonies if and when we need them.

A Mars colony, even if self-sustaining, doesn't even ensure our species survival against several plausible end of the world scenarios.

A gamma ray burst event works on the scale of *solar systems*, not worlds. If our system is sterilized by by a GRB we die, be it on Mars or Earth or the Kuiper belt. There is no defense except interstellar civilization.

The theorized quantum vacuum destabilization will end all existence in the galaxy and beyond, let alone our little sliver of it. A new pocket reality of low energy space will expand from some point, and when it reaches us at light speed our bodies and worlds and ships will just stop being things. Not even an interstellar civilization could survive. We would need FTL ships capable of crossing the unimaginable distances between superclusters to keep our species going as super clusters are receding from each other faster than light, so a Doom-o-sphere expanding at light speed will never reach us.

The sun's massively increased energy output in a billion years, predicted to evaporate the oceans and bombard the Earth with intense stellar radiation, will ironically only make Earth slightly less hospitable than Mars is right this second. Mars is already lacking a magnetosphere to predict it from radiation, its oceans have already boiled away into space, its advanced forms of life - if they ever existed - are all long dead and would need to be re-introduced by humanity to make a colony self-sustaining.

Finally, nuclear war. Contrary to popular belief, full scale nuclear war will not end all life on Earth. There are simply too many people living in too many places for us all to ever die to modern nuclear bombs - which are as far as can be done with a nuke surgical instruments for devastating the enemy's nuclear and industrial capacity. And even if we did invest in planet-killing weapons, like Szilárd's theorized 'cobalt salted bombs', ICBMs can easily become IPBMs (interplanetary ballistic missiles). Allowing politicians can ensure Mars dies along with Earth when the day comes (we all know politicians love sharing). Being on Mars buys you a weeks of life before you too are killed.

The only scenario an extra-planetary colony saves us from is asteroid impact. A big rock from space, short of a Theia-level planet-to-planet collusion which liquefies the crust, is a lot like nuclear bombardment in that there is little chance of it killing us. Again, there are too many of us and we're too spread out. So long as multicellular eukaryotic life exists, humans can exist - we fuck like rabbits and are pretty clever. The only advantage of a Mars colony is help restarting Earth's technological base after the dust clears, which why not built time capsules for cheaper?

So yes, a rogue planet slamming into Earth is pretty much the only time "humanity" really needs an extra planetary colony. And that seems so unlikely it strikes me as bizarre to try and plan around it.

The key part of the sentence is "this type". From TFA: Five years ago, Corcoran and Conner showed that tiger moths can jam the hunting sonar of brown bats. But this is the first time that this type of competitive interference among individuals of the same species has been discovered in animals, they say.

What are you talking about? I just explained why that won't happen.

America is for the democrats, and increasingly going to be so as we go forward. When this election shakes out we'll probably find that again - Democrats win the popular vote by a moderate margin, while Republicans got a disproportionate amount of seats. Of course the message in conservative circles will be parades and 3 cheers and "America really does love our treasonously obstinate ways!" but it's all down to the broken machinery of American elections (literally so in the states using Diebold).

I personally agree with you, and the trend to deny reality that exists among the PC crowd is something I find mildly irritating. But careers are at stake and some people are going to take the easy road - it's simply human nature.

Considering a Harvard president (Lawrence Summers) was forced to resign for even suggesting they *talk* about what you're saying - let alone actually argue it - yes it is that difficult for many to accept. It flies in the face of 50 years of cultural ideas about self-determination and the utter supremacy of nurture over nature.

Suppose Mars declares space war on Earth. What is the most expedient method of defeating the enemy? Well planets are huge, and slow, and predictable - and all his civilians live there. Launch a massive cloud of interplanetary nukes at his population centers and wait until he is dead or surrenders. Hopefully your point defense system is good enough to avoid the same happening to you.

Suppose Ship A declares space battle on Ship B. What is the most expedient method of defeating the enemy? Launch a cloud of nukes in his general direction that run cold until near enough to detect a heat signature. Unfortunately, missiles are an engine and a warhead so your much more complicated ship can't outrun them (more mass), and is almost assuredly doomed. Fortunately, he's doomed as well - the time it takes his missiles to hit you is a matter of days. More than enough time for you to launch an equivalent salvo in retaliation before you die.

The only time you'd see SPACE COMBAT like mentioned by the video is a major power bullying some nobody country who can't retaliate in kind. Like what happens today.