[gnulinux]

How do you know? Can we go to Mars today? What if earth gets destroyed before we can emigrate to Mars? (assume that Mars is a clone of earth i.e. the same conditions we have in Earth)

Also it's possible earth wasn't suitable for Venisian life back then.

[jerf]

Because the level of destruction imposed on Venus implies a degree of power a great deal beyond what we have now. Venus has 93 times the atmosphere of Earth. Wrecking Earth's atmosphere to that extent on a short time frame due to intelligent life's activity isn't just burning a tons of hydrocarbons, it would be going out to the Solar System and pulling in mass in quantity to be dropped in to the atmosphere. By the time they got there they ought to have the capacity to do a lot of other things too.

It isn't particularly plausible that life destroyed Venus. It's especially not particularly plausible that it just so happens that life did it to Venus using exactly what happens to be a fashionable thing to talk about here on Earth at this exact time.

[stcredzero]

They wouldn't have had to wreck their atmosphere to that extent so quickly. What if they wrecked their atmosphere more slowly, then experienced a slow global collapse of civilization due to the climate change? There could have been a "phase change" event where they retained technology, but quickly lost the ability to engage in the magnitude of project required to save their planet. "We of Souvenusia do not trust the people of Norvenusia to act in good faith in the sun-shield project!" Venusian civilization devolves into global war. Then the climate has warmed up to the point, where their wartime activities trigger a global methane clathrate catastrophe.

It's especially not particularly plausible that it just so happens that life did it to Venus using exactly what happens to be a fashionable thing to talk about here on Earth at this exact time.

But it could make for a timely, marketable, ripping good novel!

[theseadroid]

Say if we suddenly realize earth is going to be unsuitable for all life forms in a year. What would we do? I would fire as many rockets as possible to Mars, carrying all kind of life forms on earth, and hope a few of them will survive and possibly evolve to Mars' environment.

[emiliobumachar]

Even all-out nuclear war would leave the Earth far more habitable than Mars. We'd need to come up with quite the feat to extinguish life here, think steering a Moon-sized asteroid.

[gnulinux]

We do know at this rate earth will be unsuitable for human life in the future and we do almost nothing about. If it were just next year, maybe we would do more about it. But my point is we can't do much since we don't have the technology to go to Mars. Emigrating to Mars is an unsolved problem and it can remain unsolved before we wreck the planet.

[jlarocco]

That's easy to say, but how would you actually do it?

To use myself as a counterexample, I don't see the point, and wouldn't be inclined to help.

[Robotbeat]

We're trying.

I think these things are path dependent. There's not a particularly good, short-term, economic reason to go to Mars and build it up enough to be self-sustaining. However long term, it probably does improve our civilization's and species' (and perhaps life's) chance at survival. Unfortunately, we're not terribly good at long-term decision making.

It could very well be that there was a window when the hypothetical Venusian civilization had the capacity to leave en masse to Earth but by the time the matter had become pressing enough, it was too late.

For instance, it could be that advanced geoengineering techniques were able to hold off the effects of warming for thousands or tens of thousands of years which reduced the urgency leaving Venus, but over time the cost to maintain such systems became much too expensive and then some crisis (global war?) destroyed the geoengineering scheme, quickly heating Venus and destroying the advanced technological civilization and/or putting it into terminal decline.

Point is you have to do such things when you have the chance, not necessarily when it seems most pressing.

As Randall Monroe has said, "The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision." https://xkcd.com/893/

We went to the Moon ~50 years ago and soon stopped. It was somewhat of a historical accident that we went at all. It's not obvious that we will return in the future (even those efforts to go to the Moon or Mars face voices calling on even private efforts to be stopped). The future has not been written, and we don't know that it'll end up in the positive direction. But we, today, have the power to try.