Comment by autoexec
7 hours ago
> It’s a self-correcting system. The air and the water will recover, the earth will be renewed.
Sadly this really isn't the case, and there are a lot of things we can do that will permanently fuck the planet. It can't be certain that we will kill ourselves off before we cross some tipping point that will eventually turn the Earth into just another lifeless rock in our solar system.
Can you expand more on what these things are?
Life on earth survived both the Cryogenian period with 5°C mean surface temperature [1] and Paleocene–Eocene thermal maximum with esimated 27.2–34.5°C mean surface temperature [2]. For comparison the current mean temperature is 15–16°C, the preindustrial was approximately 14°C.
I'm not even sure it's easy to exterminate humanity: our species has displayed an extreme ability to adapt. Surely, billions of humans could die in a big cataclysm but it's genuinely hard to imagine an event that will exterminate every last pocket of survivors. Even harder if we speak roaches and bacteria. The "lifeless rock" will happen when the sun turns into the red giant.
[1] https://en.wikipedia.org/wiki/Cryogenian
[2] https://en.wikipedia.org/wiki/Paleocene–Eocene_thermal_maxim...
Well, "permanently fuck the planet" can be a matter of perspective. The great oxidation event "fucked up" the planet for anaerobic life, but we would not exist without it, so it was a huge blessing for us. Even human CO2 emissions could be viewed as a huge blessing for biosphere in the far future since it releases captured carbon ("the currency of life") thus significantly delaying the timeline of atmospheric CO2 depletion to levels at which photosynthesis becomes impossible.
Natures capacity to bounce back has been overestimated it turns out https://phys.org/news/2026-10-nature-capacity-species-lost-v...
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.
> 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.
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.
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That seems pretty arrogant that a hundred million years or more won’t restart life back on Earth. But I also might just be ignorant. What could we do to end all life on earth and prevent future life from forming?
Well there are some well-described scenarios of what could've happened to a hypothetical ancient life on Mars. There's some evidence suggestion methane-producing microbes may have lived on Mars 3.7 to 4.1 billion years ago that may have lead to the CO2 and hydrogen being replaced with methane, stripping away the planet's protection and leading to rapid glaciation and total extinction.
Indeed earth has itself had a few close calls with total extinction https://en.wikipedia.org/wiki/Medea_hypothesis
99.5% of life may have died during the Great Oxidation Event. 96% of all marine life may have died during the Permian–Triassic extinction event
TBH it's no short of a miracle that we're still here.
I love that word, “may.” The linchpin of so many suppositions.
Well there we go. TIL.