[smartasafruit (OP)]

What would happen if all of humanity vanishes in one second? Like just vanish and leaf all of our buildings and so on, but not our decaying bodies.  Would that stop the  climate change in an instant, or are we too far along by now? Would the rainforest slowly grow back, or is it lost forever? Can almost extinct species come back and repopulate areas where humans used to live instantly?

[Janus]

What would happen if all of humanity vanishes in one second? Like just vanish and leaf all of our buildings and so on, but not our decaying bodies.  Would that stop the  climate change in an instant, or are we too far along by now? Would the rainforest slowly grow back, or is it lost forever? Can almost extinct species come back and repopulate areas where humans used to live instantly?

Look up a book called: "The World Without Us"  by Alan Weisman
It covers this exact subject.  It starts from the time at which we disappear, and goes and extrapolates forward from there over time.

[Bored chemist]

What would happen if humanity vanishes
The newspapers would say it was because of the EU.

[searchingscience]

Hey there!
Another aspect is that the subways of diverse cities would flood after the disappearance of the humanity. Nobody would for instance regulate the groundwater and the pumps.
The buildings would take hundreds of years to degrade and the nature would slowly take over again. But it would also take millions of years until the nature would be completely recovered from our actions.
Moreover, the effects of the climate change would still be there. And the CO2 would not vanish with our disappearance.

[charles1948]

If humanity vanishes, any successor species will have a difficult job, as we've used up most of the oil.

[alancalverd]

Not a problem. No other species needs fossil fuels. Indeed half of humanity seems to exist with little or no oil consumption.

[scientistlover1]

Hey Guys,
I would agree with you. If you assume that from now on both people and their lives (i.e. buildings etc) disappeared, it would still take centuries for the environment and nature to recover and adapt to the animals. I also guess that climate change could be "stopped", but that would also take decades or rather centuries.
Best regards

[alancalverd]

Worth a look at the exclusion zone around Chernobyl. It had pretty well reverted to primeval forest within 20 years after human evacuation. Deer arrived early, quickly followed by wolves and bears. Przewalski horses are thriving and I suspect feral pigs are having a great time if they haven't been displaced by wild boar. There are now enough mature trees to support an entire avian ecology from sparrows to owls.

[charles1948]

Not a problem. No other species needs fossil fuels. Indeed half of humanity seems to exist with little or no oil consumption.

Yes but it's not just the oil.  A future successor species, would find problems if they tried to build a new industrial civilisation.

Where would  they get their essential metals from.  Most of the easily available, near-surface supplies of iron and copper ores, have been plundered by us and exhausted.

The remaining ores are deep-level,  and difficult to mine without machinery.  Which can't be manufactured without the
metal from the ores.

The successor species would thus be in a "Catch-22" predicament.  So they'd probably give up and go back to painting cave-walls and chanting nostalgic folk-songs of the "Old People" who had huge cities celestially lit,  and didn't eat each other in hard winters

[Kryptid]

Where would  they get their essential metals from.  Most of the easily available, near-surface supplies of iron and copper ores, have been plundered by us and exhausted.

It's not like all of the metals in our buildings and machinery would vanish if we were to disappear. Erosion and oxidation would degrade them, perhaps even returning them to the ground eventually. So a future species would still have access to the metals. I'm also somewhat doubtful that we have already mined a significant portion of easily-accessible metal ores (but am willing to be corrected if the relevant data is provided).

[alancalverd]

Why would any humanoid species succeed us if we were extinguished in one second? That could only happen if the world were suddenly to become toxic to the genus homo (there being no other extant species). The evolutionary split from other apes happened a very long time ago and no other primate shares anything like our genetic makeup.

Remember the question isn't about hard times, but extinction. Nothing like a dodo has succeeded the dodo - its ecological niche has been filled by very different fauna.

[Kryptid]

no other primate shares anything like our genetic makeup.

Humans and chimps are about 98% similar genetically, so I find this to be an odd statement.

[charles1948]

Nothing like a dodo has succeeded the dodo - its ecological niche has been filled by very different fauna.

As regards the dodo, give it a chance!  I's only been extinct for 300 years or so.  That's a mere blink of the eye, in evolutionary terms.  Mightn't it, or some very similar bird, re-evolve to roam Mauritius in a few million years?
 
And just as a passing thought, do you think anyone would even remember the Dodo, if it hadn't been given such a succinct and appealing popular name?

Suppose it'd only been called by its scientific cognomen "Raphus cucullatus".  Who'd remember that?

[Bored chemist]

It's not like all of the metals in our buildings and machinery would vanish if we were to disappear. Erosion and oxidation would degrade them, perhaps even returning them to the ground eventually. So a future species would still have access to the metals.

We have found places where the copper compounds occurred at high concentrations in large amounts.
And we dug it out and distributed it all-over the whorls as pipes and cables etc.
So we have made it much more difficult to get hold of metal on an industrial scale.

Any successor to hiumans would probably end up mining our rubbish tips

I'm also somewhat doubtful that we have already mined a significant portion of easily-accessible metal ores (but am willing to be corrected if the relevant data is provided).

If we hadn't used up the readily available- surface or near surface resources, we wouldn't be going to the trouble of digging deep mines.
Is further data needed?

[alancalverd]

no other primate shares anything like our genetic makeup.

Humans and chimps are about 98% similar genetically, so I find this to be an odd statement.

The remaining 2% took something like 5,000,000 years to evolve and produced at least 6 other hominid branches that have since disappeared.  Whatever causes us to disappear is unlikely to be particularly hospitable to anything like us.

The genetic DNA similarity between pigs and human beings is 98%. Interspecies organ transplant activities between humans and pigs have even taken place, called xenotransplants.

Now there's an intelligent and robust species that is already doing well around Chernobyl, formed the US presidential cabinet from 2017 to 2021, and said he would return.

[charles1948]

Is it true that humans share 70 per cent of their genes with Slime Mould?  If so, that could explain politicians.

[alancalverd]

Unlikely. Slime mould displays characteristics of intelligent, adaptive response and collaborative problemsolving.

[ukmicky]

What would happen if life as in humans suddenly vanished, not much in the grand scheme of things. New forms of intelligent life will probably again emerge and and everything that is currently happening to the earth will happen again.

If intelligent life has a model we are probably doing everything that model suggests intelligent life does as it evolves and improves its existence. I don’t condemn us humans for what we have  done  to the earth so far as it is probably an inevitable consequence of intelligent  life’s  attempt to survive . Now however we are at a point in our evolution where we are able to invent technologies that will allow us to take a different path allowing us to change how we treat the world. We can’t take a step back like some would like us to do In order to protect the earth and it’s environments but we can move forward in a more sustainable way which will eventually lead to the change that is needed.

Sorry ,probably a bit off topic near the end

[Petrochemicals]

I advise you to read this.

https://www.thenakedscientists.com/forum/index.php?topic=71332.25

It's in new theories, but it's not particularly new these days and it certainly is not a theory.

This could lead to catastrophic extinction, when the climate reaches equilibrium again there may be many animals lost.