There are no expected natural disasters in the near future that would make humans extinct.
The biggest possible threats are:
A 2010 poll found that 31% of Americans think that we will be hit by a giant asteroid by 2050. See Public sees a future full of promise and peril
In actuality - then it's most likely to be several hundred thousand generations before we are hit by one. And for one as large enough as the dinosaur ending impact - you are talking about millions of generations of humans. Those of course are long enough timescales for humans to evolve into other creatures, and for the larger impacts, long enough for small mouse sized creatures to evolve into humans.
And even that is not long enough timescale for a human extinction causing impact - if the dinosuars had had our technology, they could have survived the initial firestorm and rebuilt their civilization, and restored the planet using materials from seed banks and preserved species they took underground and under the sea with them before the impact happened.
Though smaller city threatening and tsunami causing asteroids are more frequent.
So - there is nothing at all likely to happen to us that's worth going into space to escape - not natural disasters. And as for man made disasters - well those could be caused by human colonies in space - as easily as caused by humans on Earth - even could be a result of a conflict between humans in space and humans on the Earth - so - that's no help to try to escape them by going into space. Space colonies would also probably be the first affected by loss of technological capabilities by human civilization.
Now long term, it is an issue. But - how long term - well we are talking about hundreds of millions of years there.
Some time in the next few hundred million years, then whatever species of intelligent creature then lives on Earth may well need to escape from Earth into space to survive some Earth threatening disaster. Most likely that will be because the seas are boiling dry, something that will happen about a billion years from now as the sun heats up.
But not certain - they might instead move the Earth to a more distant orbit, for instance - slowly - over millions of years, who knows what technological capability they will have then.
And - any terraforming attempts we do now are unlikely to help them. For instance the ideas for terraforming Mars are ideas that will release volatiles on Mars to create an atmosphere and shallow ocean that will last - at most - maybe a few million years. Unlikely to last hundreds of millions of years.
On those timescales
So - after the terraforming attempt eventually - either succeeded or failed - but then ran out of its volatiles - Mars would end up with no water, no atmosphere - and far harder to terraform than it is now.
That also is the optimistic view. There are many things to go wrong with terraforming and they might well not end up with a terraformed Mars at all at the end of the process if you just press ahead using only our current knowledge and ideas. Maybe even a planet that is hazardous to humans.
For some of the things that could go wrong:
But if you have that level of technology - then there is no risk at all from asteroid impacts as you just need to survey the Oort cloud - and if you can bombard Mars with comets - you can certainly divert incoming asteroids of the 10 to 100 km scale long before they hit Earth - as you'd have millions of years of warning (by then would have surveyed the entire Oort cloud most likely and know the position of every comet in our solar system larger than say 10 km or whatever).
And as for Mercury, or remote chance of a really huge thousand kilometer scale comet headed for Earth - with millions of years of warning - chances are you have the technology by then to move planets.
There are ideas for that already - we could do it with our existing technology with enough effort and expense put into the project - the idea is first to divert a large asteroid - and then with repeated flybys of Earth and Jupiter every few thousand years - it can gradually move Earth's orbit further away from the sun see
Moving the Earth: a planetary survival guide
Planet Earth on the move
So in short - not at all likely that the world will end through natural disasters. Only thing we need to worry about there are ourselves - if any technology we develop ourselves such as especially
If you want an isolated community of humans - easier to create that on the Earth than in space.
So - solution is not to try to escape from it - but to keep a watchful eye out for problems - and to listen to people who talk about these issues and look carefully at what they say - and do what one can to stop these things ever happening. Which we can do - have already solved many major issues as a species - e.g. ozone layer, DDT crisis, the Green revolution preventing massive world starvation - managed to find our way through many decades of risk of global nuclear war - test ban treaty, mass species extinction - many gone extinct but could easily have been far worse e.g. by now might be even almost no wild large mammals left (surely no whales, tigers, elephants, lions for instance) if we hadn't had successful international conservation measures, etc etc. I think myself that we can prevent our own extinction similarly - but - not by running away from the problem into space. Not yet anyway.
We may need to do it some time in the next few hundred million years - and - not us quite - but rather - whatever species we evolve into - or quite possibly by then - intelligent octopuses or parrots or dogs or some future species we can't imagine - whatever species has the best space faring capabilities on Earth by then.
The biggest possible threats are:
- Gamma ray burst - highly focused short intense beams of gamma rays - if one of them happened to be directed our way.
They are exceedingly rare - so far only observed in other galaxies. For a nearby one directed directly towards Earth - expect it to be millions of generations of humans between them - and if one did happen, only the side of Earth on the side of the burst would be affected. Humans on the other side would survive the initial burst, and could rebuild civilization and adapt to Earth and work on restoring Earth more quickly than by natural processes. Our seed banks (deep underground in Norway) would survive also, and all species living on the other side of the Earth at the time of the burst - and marine species, These could be used to help rebuild Earth. - Black holes. Collision of sun with a large black hole - we'd see it coming for millions of years. Collision with a mini black hole - that's not likely or we'd see stars blanking out all the time. In both cases, sun disappears and going to another planet won't help. Collision of Earth with a black hole very unlikely as it is far smaller than the sun.
- Asteroid impact. Yes danger of big asteroid hitting Earth. But again very rare. Ones large as the one that ended the dinosaur era - every few tens of millions of years. So - hundreds of thousands of generations of humans - not likely that the first major impact we encounter is like that. Instead - likely to be many smaller city and country threatening impacts. And in remote case one did happen - if it is as large as that, say, 10 km in diameter - then we'd see it coming at least months in advance (if it came from the Oort cloud) - and far longer in advance if it was a NEO - and could prepare for it.
The Asteroid That Killed The Dinosaurs
Space guard surveys aim to plot all the 1km or larger objects in the inner solar system with any chance of hitting Earth - and future missions may reduce that to 130 meters or larger Explaining meteors: are we in danger?
And - many humans would survive an impact even as large as tens of kilometers in diameter. No need to go into space - could survive in submarines or deep undersea or underground shelters - costs far less for far more survivors than to build lots of spaceships and habitats to survive. And after impact they are in the right place to rebuild civilization.
There is almost zero danger of an impact so large that it makes humans extinct, not with our technology. There were impacts large enough in the early solar system for the first few hundred million years. But the impact record on the Moon and other planets show that we have had no impacts as large as that for billions of years. I mean - impacts large enough to e.g. make the surface of Earth molten and boil the seas, that sort of unsurvivable event for any humans not in space. Only chance of that is a few hundred million years into the future when there is a remote chance Mercury could be disturbed from its orbit by resonances with Jupiter - and an even remoter chance that it could then hit Earth. - Global warming - to heat the Earth up enough for a runaway greenhouse effect so the seas boil will require more than ten times the amount of CO2 in all the oil reserves and coal reserves on the Earth. Projections for a hundred years into the future, worst case, is less than 10C rise in temperature. A humanitarian disaster if it happens - many humans affected, quite possibly government toppling - could be widespread suffering, hunger, - we most definitely need to deal with such issues.
But certainly not human extinction causing - some humans for sure will survive - and an Earth that's say 5C hotter is still far far more habitable than any other place in the solar system.
It doesn't make sense to go into space to try to escape from those effects, as they won't make humans extinct, or make Earth uninhabitable, not nearly as uninhabitable as Mars (say), never mind hope that billions of people from Earth could find a better place to live in space. Instead these issues should strongly motivate us to fix the issues here on Earth as best we can.
Will Earth's Ocean Boil Away?
A 2010 poll found that 31% of Americans think that we will be hit by a giant asteroid by 2050. See Public sees a future full of promise and peril
In actuality - then it's most likely to be several hundred thousand generations before we are hit by one. And for one as large enough as the dinosaur ending impact - you are talking about millions of generations of humans. Those of course are long enough timescales for humans to evolve into other creatures, and for the larger impacts, long enough for small mouse sized creatures to evolve into humans.
And even that is not long enough timescale for a human extinction causing impact - if the dinosuars had had our technology, they could have survived the initial firestorm and rebuilt their civilization, and restored the planet using materials from seed banks and preserved species they took underground and under the sea with them before the impact happened.
Though smaller city threatening and tsunami causing asteroids are more frequent.
So - there is nothing at all likely to happen to us that's worth going into space to escape - not natural disasters. And as for man made disasters - well those could be caused by human colonies in space - as easily as caused by humans on Earth - even could be a result of a conflict between humans in space and humans on the Earth - so - that's no help to try to escape them by going into space. Space colonies would also probably be the first affected by loss of technological capabilities by human civilization.
Now long term, it is an issue. But - how long term - well we are talking about hundreds of millions of years there.
Some time in the next few hundred million years, then whatever species of intelligent creature then lives on Earth may well need to escape from Earth into space to survive some Earth threatening disaster. Most likely that will be because the seas are boiling dry, something that will happen about a billion years from now as the sun heats up.
But not certain - they might instead move the Earth to a more distant orbit, for instance - slowly - over millions of years, who knows what technological capability they will have then.
And - any terraforming attempts we do now are unlikely to help them. For instance the ideas for terraforming Mars are ideas that will release volatiles on Mars to create an atmosphere and shallow ocean that will last - at most - maybe a few million years. Unlikely to last hundreds of millions of years.
On those timescales
- Water is lost from the upper atmosphere of Mars as hydrogen dissociated from the Oxygen
- Carbon dioxide would be turned into limestone in the shallow seas
So - after the terraforming attempt eventually - either succeeded or failed - but then ran out of its volatiles - Mars would end up with no water, no atmosphere - and far harder to terraform than it is now.
That also is the optimistic view. There are many things to go wrong with terraforming and they might well not end up with a terraformed Mars at all at the end of the process if you just press ahead using only our current knowledge and ideas. Maybe even a planet that is hazardous to humans.
For some of the things that could go wrong:
- Trouble With Terraforming Mars
- Imagined Colours Of Future Mars - What Happens If We Treat A Planet As A Giant Petri Dish?
But if you have that level of technology - then there is no risk at all from asteroid impacts as you just need to survey the Oort cloud - and if you can bombard Mars with comets - you can certainly divert incoming asteroids of the 10 to 100 km scale long before they hit Earth - as you'd have millions of years of warning (by then would have surveyed the entire Oort cloud most likely and know the position of every comet in our solar system larger than say 10 km or whatever).
And as for Mercury, or remote chance of a really huge thousand kilometer scale comet headed for Earth - with millions of years of warning - chances are you have the technology by then to move planets.
There are ideas for that already - we could do it with our existing technology with enough effort and expense put into the project - the idea is first to divert a large asteroid - and then with repeated flybys of Earth and Jupiter every few thousand years - it can gradually move Earth's orbit further away from the sun see
Moving the Earth: a planetary survival guide
Planet Earth on the move
So in short - not at all likely that the world will end through natural disasters. Only thing we need to worry about there are ourselves - if any technology we develop ourselves such as especially
- Nanotechnology
- Self replicating machines - especially ones small and hard to detect
- Artificial life not based on DNA or different biochemistry
- Return of XNA based life to Earth from elsewhere in the solar system - if it turns out to be better at metabolizing than DNA based life for instance, or more efficient photo synthesis or in some way out competes Earth life
- Biochemical or nano technology weapons
- Experiments that could destroy the Earth - e.g. creating mini black holes. Review of the LHC experiment showed it safe in this respect - energies were similar to those created in natural events - but maybe future far more powerful experiments could do it. But - this doesn't seem to be an issue as far as we can tell.
"To start with, theoretical physicist Stephen Hawking calculated all black holes should lose mass over time, giving it off as so-called Hawking radiation. Tiny black holes should shrink via such evaporation faster than they grow by gobbling up matter, dying within a fraction of a second, before they could engorge on any significant amount of matter.
Even if one assumes Hawking is wrong and that black holes are more stable than that, the tiny black holes would pose no danger. Because the microscopic black holes would be created within a particle accelerator, they should keep enough speed to escape from Earth's gravity. Moreover, if any get trapped, they are so tiny it would take each one more than the current age of the universe to destroy even a milligram of Earth matter."
Mini Black Holes Easier To Make Than Thought
However - it was certainly necessary to do a detailed review of the potential dangers posed by mini black holes - and we should continue to monitor and review any experiments that might have the potential to destroy the Earth.
If you want an isolated community of humans - easier to create that on the Earth than in space.
So - solution is not to try to escape from it - but to keep a watchful eye out for problems - and to listen to people who talk about these issues and look carefully at what they say - and do what one can to stop these things ever happening. Which we can do - have already solved many major issues as a species - e.g. ozone layer, DDT crisis, the Green revolution preventing massive world starvation - managed to find our way through many decades of risk of global nuclear war - test ban treaty, mass species extinction - many gone extinct but could easily have been far worse e.g. by now might be even almost no wild large mammals left (surely no whales, tigers, elephants, lions for instance) if we hadn't had successful international conservation measures, etc etc. I think myself that we can prevent our own extinction similarly - but - not by running away from the problem into space. Not yet anyway.
We may need to do it some time in the next few hundred million years - and - not us quite - but rather - whatever species we evolve into - or quite possibly by then - intelligent octopuses or parrots or dogs or some future species we can't imagine - whatever species has the best space faring capabilities on Earth by then.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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