This Is the Way the World Ends 394
Dave Knott writes "The CBC's weekly science radio show Quirks and Quarks this week features a countdown of the top ten planetary doomsday scenarios. Nine science professors and one science fiction author are asked to give (mostly) realistic hypotheses of the ways in which the planet Earth and its inhabitants can be destroyed. These possibilities for mankind's extinction include super-volcanoes, massive gamma ray bursts, and everybody's favorite, the killer asteroid. Perhaps the most terrifying prediction is the reversal of the Earth's magnetic field (combined with untimely solar activity), a periodic event which is currently 1/4 million years overdue."
Um, global thermonuclear war? (Score:5, Insightful)
What about that? I think it's still much more likely than the other options listed. It wouldn't end the Earth (nor would for example Gamma burst), but it would end the civilization and/or kill all humans.
--Coder
Overdue, eh? (Score:5, Insightful)
I always love it when people say these things. Point of fact, we don't have enough data points to make this prediction. At best, that's a wild conjecture.
What's really disconcerting (Score:5, Insightful)
I sincerely hope that we'll be able to set up colonies on other planets or in other solar systems before something snuffs out life on Earth. Our survival as a species will depend on it.
Overdue? (Score:3, Insightful)
Re:Um, global thermonuclear war? (Score:5, Insightful)
We still have those bombs, remember? What about that? I think it's still much more likely than the other options listed. It wouldn't end the Earth (nor would for example Gamma burst), but it would end the civilization and/or kill all humans. --Coder
There are humans all over the place. In some cases you'd have detonate a bomb in one area to kill a couple of people. Seems unlikely. It'd be devastating but unlikely to occur in any civilisation destroying volume.
Re:Magnetic reversal (Score:1, Insightful)
Re:What's really disconcerting (Score:1, Insightful)
I disagree. If there is only one doomsday scenario but it is almost certain, then that is much more disconcerting than 10 doomsday scenarios with 0.01% probability each. What's really important is the sum of probabilities, not the number of scenarios.
Re:Um, global thermonuclear war? (Score:5, Insightful)
If we go into biotechnology, I'm more scared of completely synthetic viruses/bacterias/nanobots. Our current tech is still way off, but one day it will be possible to create things for which humans have no resistance whatsoever. Something like polyethylene membrane coated bacterias. I know this specific example wouldn't work, but if something as exotic was created, our immune system would be completely helpless.
And chemical weapons are not even that scary. You need quite a lot of chemicals to cover a relatively small area. And most dangerous ones are organic and get broken down/degraded in nature. I don't think you would be able to kill >1% of world population even if you tried with chemical weapons. And to destroy entire biosphere- impossible.
--Coder
magnetic reversals are not periodic (Score:5, Insightful)
Perhaps the most terrifying prediction is the reversal of the Earth's magnetic field (combined with untimely solar activity), a periodic event which is currently 1/4 million years overdue.
From the record of paleomagnetism found in spreading ocean floors, the reversals are anything but periodic. Reversals recur, but the interval between reversals can be less than 25 thousand years, or longer than 35 million years. In other words, the intervals between reversals vary in duration by a factor of more than 1000.
The oceanic record is limited to the last 200 million years, at most. It has been extended further back by correlating measurements from continental rocks formed at different times, and relying on models for tectonic drift. This naturally yields inferences with lower confidence and limited time resolution. However, the results suggest that geomagnetic field has occasionally been stable for more than 50 million years at a time.
http://en.wikipedia.org/wiki/Magnetic_reversal [wikipedia.org]
Given that their occurrence is erratic rather than periodic, and that there is no decent model for predicting their occurrence, the assertion that a magnetic reversal is "overdue" is absurd.
The scaremongering that a reversal would lead to "the end of the world" or mass extinctions is equally puerile. Reversals of the geomagnetic field show no particular correlation with extinctions in the past.
Re:Most likely scenario (Score:3, Insightful)
Even the most retarded religious fundamentalist understands that dropping a nuclear bomb on someone who has one, or has a country which has one for a friend, isn't such a bright idea.
snip
Even actually been to the middle east ?
Some of the fundamentalists BELIEVE in their god. They don't care if they all die, so long as they go to heaven.
Religious fanatics (Score:2, Insightful)
Even the most retarded religious fundamentalist understands that dropping a nuclear bomb on someone who has one, or has a country which has one for a friend, isn't such a bright idea.
For some religious fanatics, it would be a bonus if the other country wiped them out in retaliation, as that would ensure all citizens a free ticket to paradise.
Usually it is not a problem, the people in the top of the hierarchies will tend to be people who are mostly interested in using religion to ensure their own power, and have no hurry to give up earthly delight for paradise. The dangerous time is right after a revolution, where you risk getting people in power who actually believe in the stuff they preach.
Re:Um, global thermonuclear war? (Score:5, Insightful)
Oh c'mon, that threat scenario is SO 80s! Contemporize, man, it's the Terrorists now, not the Communists.
Re:What's really disconcerting (Score:3, Insightful)
Looking at what we've done to this planet, I'm not so sure the survival of our species is in anyone else's interest.
OTOH making some lifeless planets flourish could be the greatest thing our species has done.
The most probable one is always forgotten... (Score:5, Insightful)
Overpopulation will kill us all before anything else...resources like oil and metals will be exhausted in the coming decades! the dramatic changes in the climate caused by human activity, the cutting down of rain forests will cause the populations of third world countries to migrate en mass to Europe and North America, further increasing the fights for the remaining resources...
Re:Magnetic reversal (Score:5, Insightful)
Also don't forget that 99% of the life on earth has a lower life expectancy and thus faster propagation cycle than us. When an animal dies of cancer after 4 years that has a life expectancy of 6 and is fertile with two, life can go on.
When humans die at age 6 on average, we die out.
Re:Um, global thermonuclear war? (Score:5, Insightful)
I'd bet on the biosphere surviving. It might not survive in a state that we'd like but it would survive.
fire off as many nukes as you like but come back in 10 million years and you'll find whatever the rats evolved into hunting each other through the forests of asia and the only remains of our civilisation will be a thin layer of dust containing higher than normal levels of uranium in the rock layers.
If you don't think the rats and cockroaches will survive then bacteria will. There are bacteria which can survive inside the heart of nuclear reactors then we're not going to kill off the biosphere with just a few hundred thousand nukes.
Even if we could blot out the sun entirely for a million years the things living around vents in the deeps of the ocean would keep going as if nothing had happened.
We will never kill the earth, even in a worst case senario we'll be nowhere near as bad as some of the significant events of the past like asteroid hits and super volcanos.
But we could kill ourselves, like bacteria in a dish slowly killing themselves with the products of their own metabolism.
Re:Um, global thermonuclear war? (Score:3, Insightful)
Actually, if you survive the blast and fallout, the big problem is nuclear winter. A full nuclar exchange would cause huge, continental fires, smoke and block sunlight for long enough to trigger an ice age. You're pretty much screwed if you crawl out of your bunker to rebuild civilisation and to find 6 feet of snow covering everything.
Carl Sagan did some work on this some decades ago.
Re:Overdue? (Score:3, Insightful)
If the Haley comet shows up one year late next time around, it'll be one year overdue.
Y'know, words have subtly different meanings depending on context.
In the case of Halley's comet, "overdue" means: "it should have been here 342 days and 17 hours ago - Hey, Frank, did you remember to factor in the perturbation from Uranus? OMG don't say the bloody thing has gone chaotic on us! What the hell are we gonna do with this space probe?"
In the case of "big ones", "field reversals" etc, "overdue" means "These things seem to come by every ten millenia or so - isn't it about time we had another one?"
The latter is a rather weaker use of the word.
Re:Most likely scenario (Score:5, Insightful)
I'm sure you haven't.
Some of the fundamentalists BELIEVE in their god. They don't care if they all die, so long as they go to heaven.
Right. And you know this how? The Saudis are rich enough to have bought all the nukes they wanted (from Pakistan, North Korea, say). And they're as devout as they come. But they haven't sent us all to paradise/hell.
Funny thing, fundamentalist leaders don't sacrifice themselves. And that goes for Muslims as well as Christians and Communists.
Ummm, probalby not so much (Score:5, Insightful)
The whole nuclear winter thing is a bunch of politics getting mixed up in science. Thus far, there has been no good proof that there's any sort of reality in it. For a decent paper on it have a look at http://www.uow.edu.au/arts/sts/bmartin/pubs/88spp.html [uow.edu.au] he covers some of the background of the politicization of the concept.
As for Sagan himself on the issue, his research seems more speculative rather than concrete. Remember he also predicted that the first Iraq war would lead to global cooling because of the particulate matter generated from the oil fires Saddam threatened to set. Well indeed Saddam did set those fires as he threatened and it had no measurable impact on our climate.
Don't confuse scientists speculating on things with real empiricism. There's lots of interesting ideas and theories, something with mathematical or computer models to back them up. That doesn't mean any of it has a thing to do with reality. That proof is separate.
String theory would be a good example. It is, in fact, not a theory. It makes no testable prediction. It's a neat bit of math and who knows, might even be correct. However at this time all it is is a neat bit of math, a hypothesis on how things might work. It won't even be a theory until they figure out how to make some testable predictions and won't be at all something to hang your hat on until there've been some serious tests of those predictions.
Re:Um, global thermonuclear war? (Score:3, Insightful)
Haven't you heard? The massive nuclear arsenels are not nearly the threat that a terrorist with a shoe bomb is.
Much simpler. We will eat the world to death (Score:5, Insightful)
The world population is increasing exponentially. Nothing increases exponentially in a limited environment, so the most likely scenario is that we will simply continue growing our consumption until we run out of the resources which allow the growth. oil, water, energy etc. Then the carrying capacity of the earth will be drastically reduced and with that goes the number of living things. In the final stages of growth humans will displace most other lifeforms which compete for resources.
You could use yeast in a bottle as an example. It grows until all the sugar is consumed, or alcohol level is too high, then it all just dies off.
Our bottle is simply larger.
Re:DNF (Score:4, Insightful)
During a simulation, the operators do not receive the blocked popups prompting them to acknowledge the exercise, and upon seeing 'multiple targets' on their inbound radar, they instigate a return strike against the 'enemy'. And so it begins...
That's totally unrealistic. No self-respecting Geek would use a GUI to control nuclear weapons. He'd have a command line interface and some shell scripts to automate the more tedious processes.
Re:Magnetic reversal (Score:4, Insightful)
In other words, it seems past examples show we really do not have to fear the end of humanity when the earth geomagnetic filed reverses. There is no record of extinctions tied to reversal events.
The Epitome Of Egotism (Score:3, Insightful)
Almost invariably when people talk about 'how the world ends' they're actually talking about human extinction. Equating the two is the sort of massive species specific ego trip that prevents people from solving the deadly problems they create, and lets them create more daily by allowing them to evade responsibility. In most scenarios the world, if not the majority of the biosphere, will continue in a more or less normal fashion. Even is such as the planetary collision that created the moon, some parts of the biosphere survived and repopulated the planet. After most of the scenarios the Earth will continue with very little evidence remaining of the very intense but very brief infection of its surface. We might fare better if we took our example from rhinovirus rather than Ebola. Killing your host is not beneficial to survival.
There's a bit in the new version of 'The Day The Earth Stood Still' that illustrates this problem in human thinking. When asked why he came to "our planet", Klaatu responds incredulously "YOUR planet?"
The Judeo-Christian argument that 'God gave man dominion over all the animals and plants' makes the same mistake (and is probably to origin of this broken thinking). It is often taken to assume that "dominion" means 'permission to use and abuse at will without repercussion' instead of the more accurate "control or exercise of control; sovereignty". The latter implies responsibility for the outcome due to application of control. No rights exist without a concominant duty. The right to live on this planet requires exercise of the duty to preserve it, at the very least by not using more than the fair share of resources. Argue against it with words all you like, Nature will respond by evolving the biosphere to include or exclude us without saying a word, or listening to our assertions of dominance or pleas for mercy. I'm betting this will be the primary message of TDTESS, with Klaatu standing in for Nature (though I'm betting he ends up cutting us some slack).
200 years ago Thomas Malthus estimated the sustainable carrying capacity of the human environment to be two and a third billion persons. I haven't seen a convincing argument with a significantly greater estimate that doesn't mistake technology as it is currently practiced (ie. non-renewable) for sustainability. We're less than 1.5 years from having 3 times Malthus's estimate.
Not with a bang, but with a whimper,
and a gag and a cough and a choke,
and pandemics and starvation,
and "natural" disasters of our own making,
and the oxymoronic "wars for survival" for dessert.
The most likely reason (Score:4, Insightful)
USA's war against terrorism triggers world war 3 and the revenge-thirst of both sides cause the whole planet to be destroyed by nuclear weapons.
Re:Um, global thermonuclear war? (Score:3, Insightful)
There is much more to the beauty of this planet than humans and their "civilizations".
Re:Tsk Tsk Tsk (Score:5, Insightful)
A much more interesting top ten would be the myriad ways that civilization could end. The next article on the main page discusses possible environmental causes of a 50% drop in sperm counts. Double that a few more times and you get a tidy end to civilization, attrition. Then there are natural or man made pandemics, massive climate changes, global thermonuclear war. How about a subtle shift in one of the universal constants of physics? The universe isn't going to keep expanding forever either. Too far fetched? Take heart, evolution is cooking up lots of nasty little things to use against us too.
My personal favorite end-of-civilization would be the global spread of a hardy airborne virus that causes plants to be unable to photosynthesize. Fin.
Now back to the news,
-ellie
Re:magnetic reversals are not periodic (Score:3, Insightful)
there is no decent model for predicting their occurrence
There is one: the Lévi distribution.
Here's a clue for an AC. The Levy distribution is not a predictive model, but a statistical description which appears to describe the historical durations between geomagnetic reversals. The statistical distribution of historical durations has no predictive value for the duration of any particular interval. It could not even predict the occurence of the last reversal, for instance.
the assertion that a magnetic reversal is "overdue" is absurd.
No, it would only be absurd for the exponential distribution.
Thanks for the laughs, AC!
Here's another clue, since you appear to need a few. The observed or inferred intervals have durations from 25 thousand years to over 50 million years, and appear to be described by the Levy distribution. However, the mathematical Levy distribution has an infinite mean and infinite variance. Therefore, if intervals between geomagnetic reversals truly conform to the Levy distribution, then there is no upper bound on the duration of such an interval. In fact, even the statistically expected value is infinite. In other words, one could never assert that a reversal is overdue. This conclusion may appear unexpected or counterintuitive, so here's summary information on the Levy distribution http://en.wikipedia.org/wiki/L%C3%A9vy_distribution [wikipedia.org]
That page was linked in the Wikipedia article on geomagnetic reversals. Did you even read it? You obviously did not read (or comprehend) the Physics World article which was also linked.
Re:Missing Option (Score:3, Insightful)
This is how suicide cults are born. Remember Heaven's Gate?
Re:Missing Option (Score:2, Insightful)
...if you're going to include a science fiction, why not include a couple biblical/religious predictions?
CBC is in Canada, not the USA.
Re:Overdue? (Score:3, Insightful)
Probabilities don't predict when something might happen, or when something is 'due'. That's a gambler's mis-perception.
If an event has a one-in-one-thousand probability of occurring in a given year, that doesn't mean it'll happen every thousand years. It means that if you look at a million year period, divide it up into 1000 thousand year blocks, you'll find that the event usually occurs once in each of those blocks. However, sometimes it won't occur at all, and sometimes it'll occur multiple times. It's just that 'once per 1000 years' is the most common frequency.
There's no way to tell, during one of those thousand year blocks, whether you're in an above-average block or a below-average block (unless the event has already occurred a few times, in which case you're clearly above average.) Therefore, you can't say that the event is 'due', even if it's been a while since the last event.
Re:Ummm, probalby not so much (Score:3, Insightful)
As for Sagan himself on the issue, his research seems more speculative rather than concrete. Remember he also predicted that the first Iraq war would lead to global cooling because of the particulate matter generated from the oil fires Saddam threatened to set. Well indeed Saddam did set those fires as he threatened and it had no measurable impact on our climate.
Did he really make this prediction? Given that he died more than three years before the war, I would be very impressed if he were already thinking about these issues.
Re:The Spaghetti Monster and the Maya, UPC codes.. (Score:2, Insightful)
Read, "The God Delusion". You will find, logically, that the probability of the existence of a God in infinitesimal. Much in the same way that I can write on a piece of paper that elephants are riding on pink space ships on the other side of the sun... now go prove that it does not exist, or that fairies do not exist, or that unicorns did not exist, etc... Most importantly, are the odds 50/50? No, of course not.
And yet you seem so close!
Re:Magnetic reversal (Score:3, Insightful)
Significant numbers of humans (say, 99%) dying would just bring us to the same global population level as during Roman Empire. Horrible, but not even close to extinction.