We probably couldn't sterilize the earth even if the entire humanity wanted it more than anything else and threw everything it had to make it happen and then some more.

Even destroying the entire humanity would be hard, civilization could go, we have plenty of scenarios for that, but killing every human, even the odd tribe of refugees who could survive in a cave somewhere is something else. I'd say it is the maximum extent of what our technology could do. By that I mean nuking everything we could nuke, including things like volcanoes, mass produce all the greenhouse gases, the ozone depleting ones, the poisonous ones just to release them all, have our finest biologists prepare a pandemic, we may even try to bring in some asteroids.

To sterilize the Earth we would need to destroy all the extremophile bacteria, the tardigrades, the deep biosphere,... That's not happening. Note that we are very careful to sterilize Mars rovers, so that we don't contaminate Mars with Earth life. That's how hardy we consider life to be.

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autoexec an hour ago | parent [-]

> We probably couldn't sterilize the earth even if the entire humanity wanted it more than anything else and threw everything it had to make it happen and then some more.

That's a rather fun thought experiment. If we were outright trying to destroy the earth it'd be pretty easy!

There are already concerns about what irreversible harm geoengineering could do accidentally. We'd just have to intentionally destroy our ozone layer again and let the runaway greenhouse effect heat the planet up enough to boil off the oceans and send the water into space via atmospheric escape. We (and most living things on Earth) wouldn't survive long enough to see the oceans become desert, but we could set the feedback loop up to continue without us.

Very little can survive without water and once the water is gone it's gone. Water wouldn't return to Earth unless it came on the backs of asteroids (which would be its own problem). The extra solar radiation would help finish off what was left.

If we were going to actively bring in asteroids, the goal shouldn't be to hit the planet with them, the goal should be to use their gravity to move the planet into a less habitable zone (https://en.wikipedia.org/wiki/Moving_Earth) or even into the collision path of another planet.

We could also put all our resources into making Grey goo (https://en.wikipedia.org/wiki/Grey_goo) happen.

	▲	Lerc 35 minutes ago \| parent [-]
		What conditions do you need for runaway greenhouse effect at 1 AU. earth has had over 20% CO2 in the past, but the sun was cooler then. Moving the planet and pulverising with an impact large enough to kill everything are firmly in the bounds of not currently feasible. I really doubt humans could do it, it would have to be done in one fell swoop, because any attempt to push the earth beyond a tipping point for bacteria to be killed would require pushing for longer than we, the pushers, could survive. We would have to be better at designing than evolution to make Grey Goo, otherwise evolution would probably have already done it, and it has, to date, designed some pretty out there things.