
How Long Does Mass Extinction Take? - zvanness
http://www.smithsonianmag.com/science-nature/how-long-mass-extinction-180949711/
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jofer
I'm impressed, that's a surprisingly good pop-sci-style article. The writing
is clear, correct, accessible, and a nice summary of the scientific context
for the paper in question. The original PNAS article is also clearly linked.

At least with geoscience, science journalists usually manage to get things
horribly wrong. Judging from previous articles, Helen Thompson (the writer)
looks like she might be a biologist instead of a geologist, but she nailed the
subject matter, regardless.

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mathattack
I agree - well written. Perhaps the only quibble is that my intuition was that
it would be much shorter. 60,000 years (or even 5,000) is a long time to
react.

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AutoCorrect
you say react as if there's an awareness by the group of organisms that they
are dying out, when that's far from the truth. Think of a species as a
network, with the leaf nodes around for only a specific length of time. Add in
several events that isolate portions of the network, and it dies off in
spurts, as each isolated portion becomes less fit and eventually ceases
reproduction.

With the decline in our birthrate, it will be interesting to see (from a
historical perspective, I'll be long dead) if we die out, or if we get out of
this funk we're in now.

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mathattack
I think the decline in birthrate helps us. If we get to under a billion, we
strain the planet less. But there are plenty of other ways for us to make
ourselves extinct.

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rquantz
This reminds me of the recent episode of Radiolab that suggested the
extinction event at the end of the Cretaceous might have taken only a few
hours[1]. If you thought this article was pop-y, you might be in for a
surprise, but I found it quite entertaining.

[1]
[http://www.radiolab.org/story/dinopocalypse/](http://www.radiolab.org/story/dinopocalypse/)

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ChuckMcM
Its a great way of trying to get a more precise timeline. Now I wonder if we
should start planting radiometric time capsules, time capsules with long half
life materials, a description of what is happening, and a bit of isotope and
its stats. Every 10 years you could do another one. And when the next
extinction hits, should the life after that be intelligent again, they could
find this set of events and date them relative to where they are now. Perhaps
we could finish with "Hey we were too silly to leave the planet, don't make
that mistake, its totally worth it to figure out how to survive off planet."

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erikpukinskis
I've heard this "survive off planet" concept over and over, and inevitably
someone points out that even after the worst conceivable environmental
disasters, Earth will still be more habitable than any planet within 1000
years travel.

And I've never heard a compelling response to that, so why do people still
think leaving the planet is important for our survival?

The only scenario I can think of where a radiation-soaked pocket in the
Canadian mountains is less habitable than "off planet" is when the Sun starts
dying. But that's not really a pressing concern.

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Steuard
If we had a self-sufficient colony on Mars (or wherever), that could provide a
reservoir of both population and (perhaps more importantly) civilization and
technology that would allow our descendants to return and re-colonize the
Earth (or rebuild its infrastructure) after a major disaster.

Even though Mars is clearly less habitable than Earth in general, the point is
that the humans living there would be _ready_ for it. If there were a disaster
here that killed off most of our crops or something, society would collapse
and have trouble recovering.

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lutusp
Given the relative conditions on Mars and Earth, the hypothetical disaster
befalling Earth would have to be pretty horrendous for life on Mars to
represent a positive alternative.

I think we should colonize Mars, not because things on Earth might become
impossible, but just because it's another planet, suitable for some
adventurous, hardy souls to colonize.

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Steuard
I'm not claiming that life on Mars would ever be _easier_ than life on Earth.
But there are plenty of ways in which nasty things could happen on Earth that
the population here is simply not prepared for. A major asteroid impact or
supervolcano eruption could cause terrible weather for years (even if we don't
go all the way to the "atmosphere is a pizza oven" point), and it would be
awfully tough to keep feeding our cities. At that point, most industry
collapses, and we're all interdependent enough that the ripple effects could
wipe out the vast majority of the human population, or even all of it.

Having a self-sufficient population on (say) Mars would make it likely that
_some_ portion of human civilization would survive such a disaster. I guess
you might argue that we could achieve much of the same effect by using the
same technologies to establish self-sufficient populations in safe(r)
locations right here on Earth: underground or deep underwater, for example.
But those would still be _more_ affected by local disasters than a colony off-
planet would be, and I feel like it would be harder to recruit people to live
there (and harder to guarantee that they were truly self-sufficient). As you
say, Mars would attract the adventurous. The Underground Civilization Vault
would just attract the astoundingly paranoid.

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erikpukinskis
We already have massive redundancy on earth: Different cities. Different
continents. A supervolcano would destroy at most a few continents.

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lutusp
> A supervolcano would destroy at most a few continents.

Just for perspective, 70,000 years ago a supervolcano eruption in Indonesia
with global effects nearly wiped out the human race
([http://en.wikipedia.org/wiki/Toba_catastrophe_theory](http://en.wikipedia.org/wiki/Toba_catastrophe_theory)).
On the basis of genetic diversity studies, it's estimated that all but
somewhere between 3,000 to 10,000 people were killed.

We may think ourselves immune from the consequences of a similar super-
eruption today, but for most people in the world, people who aren't rich and
who can't create a well-stocked underground shelter, the risk is very high.

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lettergram
I really enjoyed this article, well written and informative.

That being said, it seemed to be posted with perfect timing; I was thinking
about this walking to work today. What if all of these mass extinctions
(hypothetically or other wise) were caused by some species on the planet
similar to us. Granted there is NO EVIDENCE for this, but what if... It seems
that all mass extinction events happen in similar ways, each time some parts
of an ecosystem are disturbed and it collapses.

Then, the most highly adaptable (fungi, bacterium, viruses are the most due to
their short lifespan) survive. It's interesting to note that it took 30,000 -
50,000 years for the humans to develop this extremely complex society and
ecosystem. Perhaps so short that when if we were destroyed this very day
nothing would remain, say from nuclear war. All of our buildings would decay
and there would be very little remnant in the fossil record.

I am not claiming any of this to be true, nor do I even believe any of it to
be true. It was just an interesting thought I had that horrified me, and I
felt I would share it.

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nicholas73
I doubt there wouldn't be evidence. A steel building frame probably preserves
better than bone. A global population of tool making beings should at least
leave some fossil evidence even if their timeline was only 30-50k years.
Lastly, the distribution of natural resources might leave some evidence (like
not finding ore where you would expect it).

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DougWebb
Have you seen a steel bridge lately? They require constant maintenance to
prevent them from rusting away. Even stainless steel will rust eventually. The
only thing that lasts more than centuries is stone, and only the really hard
stones will last for thousands of years.

The other problem is location. Humans like to build on coastlines, and
coastlines shift. We have very little evidence of ice-age era settlements
today, but the few sites we do know of show that there were some pretty
sophisticated societies around at the time. It's very likely that there
are/were more sites, but today they're under a few hundred feet of water off
our coasts.

As far as natural resources: apparently there are extensive empty holes in the
ground around the great lakes that used to be full of copper ore, based on
what's left in the walls. So much copper ore that the mining must have gone on
for centuries, or involved tens of thousands of people. No one knows who did
that, but a likely possibility is the Phoenicians during the Bronze Age. So
that's one example of the type of evidence you're talking about, albeit for a
more recent period. To go back much further, we'd have to know what kind of
resources they were after and where, and hope that the landscape hasn't
changed so much that we can't recognize the evidence of resource mining.

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Blahah
John Baez's excellent Azimuth project has a really good summary of current
scientific understanding of mass extinction events:
[http://www.azimuthproject.org/azimuth/show/Extinction](http://www.azimuthproject.org/azimuth/show/Extinction).

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lafar6502
Previous mass extinction took 60000 years so even if another mass extinction
event is happening now we won't even notice it.

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hyperbovine
Because a_k = x implies a_{k+1} = x for all k.

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lafar6502
how did you know?

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duvander
Between 12,000 and 108,000 years

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DanielBMarkham
Mankind has most likely already passed an extinction level event with the
creation of solid-state circuits.

So I guess we'll be finding out shortly (i.e., the next 100-1000 years)

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ASpring
I don't follow. Care to expand?

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benjamincburns
I think what he's trying to say is "we're all gonna die!!!!"

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vanderZwan
But how would that follow from solid state circuits?

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rubinelli
In one word: Skynet

