What would the Earth look like if humans disappeared?

Cecil’s column: http://www.straightdope.com/columns/read/3269/what-would-the-earth-look-like-if-humans-disappeared

I’ve read the Alan Weisman book he refers to, The World Without Us, and it’s fascinating. One point Cecil doesn’t mention is that nuclear power plant, hydroelectric dam and oil refinery failures would be inevitable - and very messy - soon after all humans disappear.

I never read the book, but I did watch Life After People.

I loved where Cecil commented “I can’t say it’s not an alluring proposition, and — helpfully — one that was broached this year by researchers at Denmark’s Aarhus University. They came to the fairly obvious conclusion that, sans Homo sapiens, the rest of the world’s fauna would be a hell of a lot better off.”

I wrote years ago, “The single best event for Earth’s biological diversity since we evolved will be our extinction.”
from The Notebooks of Maggie A - Part Six

I seriously doubt Mt. Rushmore will last as long as predicted. Fine erosion may be slow, but bigger chunks will fall off faster, exposing more area to the elements. Without maintenance the faces will be unrecognizable before too long. I don’t think gas lines will easily explode either, because they’ll be empty from leaks fairly quickly. The pyramids in Egypt and other such structures around the world may outlast all of our modern artifices.

But will the pyramids be visible? I’d expect that sands would cover them in not too many hundred years, given an expansion of the Sahara from warming.

If you start counting hidden human goods, then buried treasures and sunken gold would be around for a very long time.

Thing is, as appealing as that sounds, the assumption that we would not be replaced by some much worse thing is a bit of wishful thinking. Whatever that creature might be, it would probably not do quite the same stuff as we do, but there are plenty of ways a rising macroparasite could mess up the global ecosystem as much as we have.

Possible. But it never happened before us and I hope it won’t happen after us. My hope is that we die in the mass extinction we’re causing (the irony of that appeals to me) and, in a few million years, the biodiversity will recover from what we did.

But, who knows? It could be like Childhood’s End where Homo sapiens evolve into their true, ultimate, selfish jerkiness and literally destroy the entire planet because they need it for something. And screw every other species that needed the planet to live on.

Probably not. They’ve survived this long because they’re basically piles of earth, just like all the other pyramids and mounds we know about around the earth. They can get covered up or grown over without collapsing. Pretty good strategy for longevity, not so good for interior space.

Well, we believe that. We assume that a previous intelligent species would do the kinds of things we do. That is not altogether certain. They could have been like large soft centipede-like creatures that propagated by dividing at segment boundaries, thus passing on knowledge directly, through a body-length brain, so that the children would not have to re-learn everything. And their work is obvious: they were geniuses at genetic technology, creating absurd leviathans to clear the jungles for them, and to fly upon. Beasts that over-consumed the available resources, causing the ultimate downfall of the intelligent centipedes.

Or not.

Not really, in the greater scheme of things. None of them really compare with a decent volcanic eruption, and a dam failure is little more than a localised tidal wave.

One statement threw a red flag for me: “It’s another few centuries before trees really recolonize the place.” Maybe this is so in the Eastern USA, but here in the West the forests would re-establish themselves much more quickly. Just mowing a Douglas-Fir will kill it but with no one to push the Snapper around there’d be a full climax forest within a hundred years. I base this claim on my personal observation of a D-Fir I felled last year … 100 foot tall … 95 growth rings.

Trees certainly can grow to great heights in 100 years, but it takes time for them to move laterally into new areas. So existing forests that have been partially cleared will grow and thicken rapidly, but reclaiming large clear cut areas would take some time.

Some parts of the west, anyway. Large swaths of Wyoming, Colorado, New Mexico, etc, etc, will most certainly not be taken over by forests. All of the 11 US western states have large spreads of land that will remain relatively clear of trees, as do the adjacent plains states.

It would seen to me there would be a much more immediate occurrence that I have never heard addressed and that is the meltdown of every nuclear reactor on earth. I do not know how many there are but I would think every land based power plant as well as every ship and submarine that is nuclear powered would melt down in a matter of days. This enormous amount of radioactivity worldwide would have to have some detrimental effect on all plant and animal life. (?)

In terms of the global ecosystem, the amount of radioactivity in all the nuclear power plants and naval drive system is comparatively trivial. Local effects would probably be nasty, but in general, not so much.

As plants took over, they would absorb most of the carbon out of the air, causing another ice age – if a nuclear winter has not caused one already. This process might occur even if we didn’t disappear. A warming earth and plenty of atmospheric carbon is liable to encourage plant life already.

The dinosaurs had their day. They are gone. The elephants, the polar bears, the rhinoceroses are approaching the end of their evolutionary day. And our time may come as well. I don’t think disease or nuclear war is going to kill us. We will simply destroy the ecosystem that supports us and makes us possible. I cannot imagine that we would be the first creatures that ate everything and then disappeared, though we might be the first that had a worldwide distribution.

Anyway, blaming everything on the Republicans seems a bit over the top – extremely silly, even. I haven’t noticed that Al Gore has done anything to reduce his carbon footprint. Kerry’s remarks at the Paris climate talks showed profound ignorance of the issue even as he lectured Republicans on their ignorance – he seems to think that CO2 is a thin layer at the top of the atmosphere and that earth’s temperatures have not varied in millions of years. I guess he forgot about the ice ages.

I am reminded of a Far Side cartoon where there is a conference of dinosaurs and the speaker is saying something to the effect of “We are in serious trouble. An asteroid is approaching, the earth is cooling. And we have brains the size of walnuts.”

Apparently big brains aren’t enough.

could be worse. I sincerely hope that we don’t discover teleportation and end up destroying ALL the planets, not just this one.

It makes me laugh when I’m watching an episode of Star Trek and they find some ancient civilization that’s been extinct for half a million years but their power reactor is still on line and the computer is still operating.

I’m not a trained ecologist, but I can verify that from experience. A tornado went through my neighborhood in 1986, tearing every single mature pine tree down in one area, making a meadow out of heavy forest. Although you can see definite signs of natural recovery 30 years later, it isn’t anywhere close to a heavy forest now.

In contrast, where man has replanted after the tornado – we have some real tree-huggers around here – the forest is 80% recovered in thickness, although the trees still have some vertical growing to do.

So you expect warming to continue with no human activities to fuel it? If that’s the case, why are we so worried about anthropogenic warming now?

Oh, I cover that one as well in another Notebook:

“If there’s another Earth-like planet out there, keep us the hell away from it. Look at what we did to this one. Frankly, I’m not sure if we should even be setting foot upon this solar system’s two water moons because look at what we did to our oceans.”
The Notebooks of Maggie A - Part Ten

I sent an early version of that to Neil deGrasse Tyson after I saw him on some show waxing poetic about humans leaving the Earth and colonizing other worlds. Never did hear back from him. Space travel is one subject I’ve done a complete 180 on from when I was young.

Huge difference in the parts of Mount St. Helens that were replanted versus areas left to recover naturally.