If people should all vanish, die out etc., how long would it take

[Hardrada]

for the Earth to regain its health, the oceans to be clean again, the rivers to run clear, the struggling endangered species to regain numerical strength. How long?

[rzemanfl]

1. Just a moment of geological time. n/t

[Radio_Lady]

17. You're exactly right. In the Museum of Natural History in NYC, I recall

seeing a wall with a time-line. It started with the beginning of Earth -- not the seven day version they spoke of in the Bible -- but eons ago. I think the line was about 20 ft. long, of which just the last few inches (centimeters?) was the part where humans evolved.

We're just not as important as we think we are. We're just a grain of sand revolving around a minor star, which will eventually explode and encompass Earth and the other planets, then die out as an astronomical cinder.

After you think about Earth, think about the "billions and billions" of stars out there in the Universe, some with potential for life.

I'm not going to sweat it. I won't be around until the end of time -- just a few more years, really.

In peace,

Radio_Lady

[w13rd0]

2. We've created a lot of waste...

...that would outlast any single one of us, even to several generations. Yes, in geological terms, a moment, in real terms, probably 10 to 50 thousand years. That's for all traces of us to be wiped away. For the ecology to recover, about 1 to 5 thousand.

[Cleita]

3. Don't plan on it as long as there is some sustainable place

for them to live. Humans are wickedly adaptable to harsh environments. However, if we were reduced in numbers so that only a few of us remained to repopulate, it would give the earth time to heal herself.

[DireStrike]

4. 100 years maybe?

Of course the plastic and long-lasting chemicals wouldn't go away. But they'd get buried and ignored, unless something evolved to use them.

Earth was never a particularly nice place though. 99.9% of all species that have existed are extinct now. Not to excuse our actions...

[Xithras]

5. A human dieout would be terribly damaging in the short term.

Without additional factors, if humans simply ceased being an influence, most of the natural world would recover in just a few decades. Some environments, like New York, would take centuries to revert to a natural form, but MOST of the world would bounce back fairly quickly.

But that's not what would happen if we died off. Why? Because we have an immense technological infrastructure that requires MAINTENANCE to keep under control. Without humans, many of the artesian oil wells would begin spilling oil uncontrollably. The nuclear reactors would all eventually breach. The chemical plants and storage facilities would all begin to leak. The damage wrought over the first decade as our infrastructure disintegrated would be ENORMOUS. Heck, just the effects of our nuclear weapons falling apart would be enough to sterilize vast swaths of the planet.

[Karenina]

6. Wir werden Venus.

Mars, anyone?

[Totallybushed]

7. My guess would be about 100 years

Except for any radioactive spots, of course.

The atmosphere and the oceans would "cleanse" in a year or two, but the disappearance of man would upset the ecology drastically, like it did when the white man landed and diseases killed up to 90% of the pre-Columbian Native American population.

There's a theory that th evast flocks of pasenger pigeons still existent in th 1800s were the result of the ecological devestation that the disappearance of man wrought on the North American continent, so we are talking about over 400 years.

Of course, the reason the ecology didn't right itself in that time is that man contnued to come over and disrupt it.

[Redstone]

8. It'd be a pretty boring place, though.

Redstone

[Jeroen]

23. I don’t think monkeys or dolphins subscribe to that point of view ;-)

[Redstone]

26. I don't care what they think. I'm not one of them. We humans have every

but as much a right to exist as they do, don't we?

Redstone

[lonestarnot]

9. 1/2 life of depleted uranium?

[Tesha]

31. Depleted Uranium is a *NON-FACTOR*.

For all the talk it spurs here on DU, DU is a *NON-FACTOR*
in this (hypothetical?) end-of-the-world scenario.

One: There ain't all that much of it compared to the Earth.

Two: It's half-life (millions of years) tells you that it is highly
non-radioactive as radioactive substances go. Globally, granite
rock faces almost certainly make a much larger contribution to
the overall background radiation.

As someone above correctly observed, if you want to worry,
worry about all the spent fuel and nuclear waste that we've
got "stored" around the globe. That's far more dangerous
than all the DU we've ever made.

Tesha

[pitohui]

10. kirtland's warbler would be extinct the very next year

a lot of species would go instantly extinct because without human maintenance they would be gone already, the usa would be forever changed since most of our "signature" species from california condor to kirtland's warbler fall in that category


we have a duty to survive, too many species would be replaced by brown-headed cowbird and never seen again if we die

[XemaSab]

20. I dunno about all that

I think the cowbird population would crash in most areas of the US. They're too disturbance dependant.

[Freedom_Aflaim]

11. What does it matter?

If their is no sentient life for Earth to support, then Earth is no more or less important than the other billions of planets out there.

Earth is only special because its the only one we know of that can support sentient life.

Without intelligent life, Earth is nore more special than any other large rock in space.


Now I know what you are trying to say and its a good point when you are trying to consider the harmful affects that humanity has on *our* environment. Every moment we are doing terrible things to our environment that lessens our ability to thrive.. But once the last human dies, Earth is no longer special. Even if it were, who would it be special to?

[pitohui]

12. many sentient species other than humans

i suspect you don't know what "sentient" means, many people don't

even crows are sentients

even doves (dumb ass but pretty birds) are sentient

your argument would be stronger if you knew what you were talking about

[Freedom_Aflaim]

13. Crows?

Hmm kay. Its not my intention to lump the intelligence and self-awareness of crows and humans together. I suspect you know that.

I apologize for using the wrong word.

What would you use in place of "sentient" to describe the ability of mankid to think, adapt, love, create, hate, build, destroy, and do all the wonderful and terrible things that we are capable of?

[pitohui]

24. i accept that you don't know what sentient means

however i won't do your homework for you, you learn nothing that way except how to copy

[Freedom_Aflaim]

28. Excellent

I was wondering how you would manage to escape the point.

Do you spend alot of time pointing out nuances of definitions? Thats proably easier than having an actual discussion I would imagine.


I'm going to give you a big blue ribbon for being so smart, although with a pat on your back.

[XemaSab]

21. What other planet has even a microbe on it?

:shrug:

[Freedom_Aflaim]

25. Strong Evidence suggests that Mars may

http://www.lpi.usra.edu/lpi/meteorites/mars_meteorite.html

There is also quite a bit of evidence that water lies beneath the surface of mars and one of the moons of Jupiter. We've yet to find a place with water that doesn't have microbial life.

Even if we later learn that there is ZERO life beyond earth, there is nothing special about anything, including Earth if there is no one for it to be special to.

Its a variation on the philosophical question of a tree falling in the forest, if no one is around to hear.

[XemaSab]

27. That's nonsense

Unless a planet supports people it is worthless?

So if we find another planet that is like Earth only with no people it's just a cosmic "meh?"

[Freedom_Aflaim]

29. No that would be a huge find. Hardly worthless

But the key to understanding the point is that it would be worth something TO someone.

If no intelligent, selfaware, sentient beings existed, then "worth" and "special" has no meaning as their very meaning is derived in the minds of those beings.

Not to mention that your very scenerio defines that there is a "WE" to find it.

However in the original scenerio by the original poster, there are no intelligent, self-aware, sentient beings. In that case no blob of mass is any more or less important than any other blob of mass.

[slackmaster]

14. Great Zen question

Since clarity of rivers, etc. is defined by humans, if humans are gone there wouldn't be anybody around to answer.

[Cleita]

15. Something interesting I read in a science magazine a year or

so ago. The DMZ (demilitarized zone) in Korea, the strip of land between No. Korea and So. Korea, has turned into a Garden of Eden of sorts. Since it's off limits to people, a wide variety of plant and animal life has sprung up in an ecological paradise. The Korean war isn't over, but a cease fire was brokered in 1954, so that's 52 years ago.

Apparently, much of it could be restored in fifty years if the DMZ is used as a yardstick. I also noticed in my back pasture, that once my neighbor took her horses out of it, that the natives started popping up, trees grew and wildlife moved in and that was just four years ago.

[Johnny Noshoes]

16. It was only a game but...

ages ago I was playing around with that Maxis Game "SimEarth". I set about to really screw up the planet just to see what would happen. Well I messed it up pretty badly and then just let the sim run for a several turns. The planet fixed itself and came back to equilibrium. Now of course it was just a simple sim and who knows how long the real thing would take to right itself. The poster who mentioned all of our unattended tech is probably right in that without us around to take care of it it would reek havoc until it was spent. My guess is it probably would take about 20-50 thousand years for things to get back to some kind of normal.


"All things share the same breath - the beast, the tree, the man, the air, shares its spirit with all the life it supports." Chief Seattle

[Freedom_Aflaim]

30. That was a fun game

I wish they would do a new version of it.

[bloom]

18. The earth is in the process

of returning to slime:

http://ktla.trb.com/news/la-me-ocean30jul30,0,799834.story?coll=ktla-news-1

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=364x1770090


Where it was about 500 million years ago.


Who knows what else will last.

[lumberjack_jeff]

19. If the purpose of the earth is just to grow stuff...

... then pretty quickly. (Assuming that whatever killed us didn't kill the rest of the biosphere - a big leap)

However, I think that the fact that we're the only creature in the known universe with the wherewithal to contemplate that concept means it'd be a big loss - even if we did bring the catastrophe on ourselves.

I'm of the opinion that we're alone and that humans will never find another planet harboring life, especially not intelligent life.

[Hardrada]

33. I think they are out there.

I just think they are scared of us.

[XemaSab]

22. I think 90% of the disturbance would be fixed within 20 years

The other 10% would take centuries, at least.

[savemefromdumbya]

32. thousands of years