Our resources would be better spent elsewhere. I know that this opinion is anathema on a tech-heavy site such as this one, but I must nevertheless express my respectful disagreement. It would be far, far more productive for the species to dedicate resources towards CO2 and CH4 reduction in the lower atmosphere.

Space travel is fundamental to the human species living sustainably in the long term. Correcting greenhouse gasses doesn't help us if the next day we find a planet-killer asteroid is a few weeks away.

In this regard, the comment about CO2 is actually much more pertinent than it seems at first. If we manage to screw up the climate in this century (which seems very likely these days), inundating every coastal cities in the world, "sustainable space colony" will have to wait a bit longer. Much longer. If you're worried that an asteroid might hit us 500 years from now, you might want to rethink your priority.

Advancing chemical rockets now is important, but compared to the scale of space colony, it feels somewhat like producing better vacuum tubes to make sure (say) the US is the first to create strong AI. Any sane 50s US leader would have understood that "trying not to have a nuclear war with Soviet" is a much more important goal anyway: you can't fund AI research if your country is a radioactive wasteland.

We went from not flying anything heavier than air to going to the Moon in 66 years. If we really really wanted to, we could go to Mars in thirty. This is a problem of priorities, not technologies (although the technological problems are real, they are not insurmountable).

CO2 is a direct and immediate threat.

Unless the lead time is 50-100 years, years might as well be tomorrow, it's going to kill us all either way. Even that might be stretching it.

> Humans as a species will survive CO2

Maybe, personally I believe humans will cause their own extinction. I'm just not sure yet if we're going to take all life with us or not. Dealing with CO2 is a toss up between making the planet uninhabitable or completely inhospitable to life.

So... what, we just halt development of all vehicles, globally, period? Bye-bye trains, planes, cars, bicycles, and buses?

You can't develop the future of transportation or the future of propulsion systems if you literally shut down global commerce.

Besides, an airplane (for example) is not wedded to the engine. Developments in prop planes carried over directly to jet planes, once the jet engine matured. Any future propulsion system that can replace jet engines will probably not be hard to work into many plane designs of the day.

Better to make incremental progress on poverty, without constraining the innovators to work on problems that don't interest them, or that seem even more intractable than e.g. space travel or AI.

Those same < 10 000 people probably doesn't know nor have the ability to fix all the problems on Earth, but they might be able to get to Mars.

Parent: See that little blue dot in the night sky? That’s Earth.

Child: What is Earth?

Parent: Earth was the planet of our ancestors, before people came to Mars.

Child: Who lives on Earth now?

Parent: Nobody. It’s a dead planet. The actions of rich, selfish people destroyed it.

Child: How did the rich, selfish people destroy Earth?

Parent: They burned it up as fuel, getting to Mars.

That proverbial man who plants trees knowing he will never sit in their shade is proverbial for a reason.. it's an amazing and heartwarming little saying because it's a contrast to how we generally behave, as individuals as well as organizations and masses. We learn from repeated catastrophe.. sometimes, maybe. But this problem is not one we can have a lot of attempts at solving. Right now we are still moving into the wrong direction, and probably even accelerating.. sure, hitting a wall can make people change their direction, but not if it breaks their neck, so to speak.

I'm not enormously optimistic. I'm just saying that compared to interstellar travel, avoiding fossil fuels seems like a fairly small problem.

The biggest lever we've got right now is computation, so yeah maybe it would be more efficient to develop AI / IA first and then mass space travel, but we can't be sure.

Also, fundamentally we can accept a few billion deaths. That sounds and is grotesque, but it wouldn't be the end of humanity. I don't see how climate change kills us all in the next 100-500 years.

This is a false dilemma. We have 7+ billion people on the planet. There is most certainly a significant amount of effort going towards the future you mentioned. They are not mutually exclusive (and are, most likely, going to be a product of each other)

At least with the mass extinction there are prospects for fixing the problem.

I wonder what the carbon footprint of space tourism is, and will be if it becomes cheaper and more popular? I feel guilty flying on a plane.

Let's go see the universe, and take life along with us.

Meanwhile, all of the derivative research (effects of zero gravity, life support systems, shielding, re-entry, etc) stagnates. And I guess we should dismantle our satellite systems as well, since they require rockets to achieve orbit.

Maybe we should ban all cars while we're at it, since they pollute our environment. We should shut down the evil factories, too, so no electric cars, either.

Yup, we can just sit in a circle, singing kumbayah while we wait for that miraculous perfect power source that someone else will develop for us. Then, and only THEN, can we continue with "progress".

We can afford to send up a couple of hundred tons of prokaryotic spores every year until the cows come home, with solar sails to get their packages up above solar escape velocity. Over a few decades or centuries that's a lot of unicellular organisms to scatter on the direction of exoplanets; we can hope that in a few million years one or another strikes edible dirt and begins to reproduce.

This is, however, not as mythically resonant as "space: the final frontier" ...

No, thanks. I prefer to believe that this task is what our intelligence is for.

Bacterial colonization is a useful argument for interrogating the "we must colonize spaaaace!" folks' intentions. I mean, why exactly must we colonize space?

"Before the sun leaves the main sequence of the Hertzsprung-Russell diagram/the Earth is hit by a comet or irradiated by a GRB" is a meaningless argument. These events happen on a time frame of hundreds to thousands of megayears; while the mean life expectancy of a mammalian species is on the order of one to ten MYa, and for a hominid species like us, it's well under one MYa. These arguments don't hold water. Furthermore, we coevolved with our biosphere and we're really badly adapted to existence without a large subset of it: calling for human space colonization is implicitly a call for terraforming/transporting a viable terrestrial biosphere to other worlds. Which brings us neatly back to bacterial colonization, because that's part of the package deal.

While I can't refute the quasi-religious imperative implicit behind the rhetoric for space colonization, I wish its proponents would recognize that it's essentially a faith-based ideology!

The Antarctic being a barren wasteland makes it an attractive breeding ground for penguins precisely because it's so inhospitable to anything alive, penguins included. As long as penguins suck less at living in a barren wasteland than their predators it's a net benefit for them to be there, despite the hardships of the environment.

If we assume there is a group of humans that feel existentially threatened by other humans so much that odds of surviving in an irradiated subterranean Mars colony beat the odds of being exterminated here on Earth, it would be a perfectly rational choice for them to try and move somewhere out of reach.

There are lots of potential scenarios why such groups might come into existence, and not all of them involve outright genocide. For example, a group could form just as a result of concerned citizens wanting to go to some place very, very remote once kids start playing Pokemon with their newfangled RNA synthesizers.

No, we're not going to move a billion or two people with them, but that's not what we need to make humanity multi-planet.

It might be hard to argue that our industrial pillage of the planet is solely a result of exploration. Anything weaker than that and I think you have the tougher position.

More recently Oil is currently driving a lot of exploration into the oceans and other remote regions.

PS: Not that I think we should all just stay home, but whitewashing history is stupid.