Which catastrophic risks does a mars colony mitigate?
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Climate change : yes
If a Mars colony mitigates catastrophic risk (extinction risk?) from climate change, then climate change is not an existential risk to human civilization on earth.
If humans can thrive on Mars, Earth based humanity will be able to cope with any climate change less drastic than transforming the climate of Earth to something as hostile as the current climate of Mars.
Supernova, GRB : probably ? Unlike impactors, a supernova or GRB would affect both Earth and Mars. However, if the major impact on Earth is deaths by radiation of exposed people and destruction of agriculture by destruction of the ozone layer, then Mars should be much more resilient, since settlements have to be more radiation hardened anyway, and the agriculture would be under glass or under ground.
Is not a good addition. The Mars-hardened facilities will be hardened only for Mars conditions (unless it’s extremely easy to harden against any level of radiation?) in order to cut colonization costs from ‘mindbogglingly expensive and equivalent to decades of world GDP’ to something more reasonable like ‘decade of world GDP’. So given a supernova, they will have to upgrade their facilities anyway and they are worse positioned than anyone on Earth: no ozone layer, no atmosphere in general, small resource & industrial base, etc. Any defense against supernova on Mars could be better done on Earth.
Good point. Mars would only be better off if the colonies over-engineered their radiation protection. Otherwise anything that gets through Earth’s natural protection would probably get through Martian settlements designed to give the same level of protection. It might be relatively cheap to over-engineer (e.g. digging in an extra meter), but it might not.
It might be relatively cheap to over-engineer (e.g. digging in an extra meter), but it might not.
FWIW, while researching my Moore’s law essay, I found materials claiming that underground construction was more expensive but paid for itself via better heating/cooling. But that was for shallow cut-and-scrape constructions and I suspect 1 meter wouldn’t take care of supernova radiation.
I suspect 1 meter wouldn’t take care of supernova radiation.
As far as I understand the issue, the danger is mainly from the temporary ozone layer depletion, with the resulting solar UV rays doing most of the damage, and not from any kind of direct supernova radiation. And UV is not hard to shield from.
Hm, so you’re right: http://en.wikipedia.org/wiki/Near-Earth_supernova#Effects_on_Earth In that case, it doesn’t sound like that much of a direct threat at all: we can use cheap underground or UV-glass-filtering greenhouses to grow our food. A disaster, but not really an existential threat.
If a Mars colony mitigates catastrophic risk (existential / extinction risk?) from climate change, then climate change is not an existential risk to human civilization on earth
This does not follow. One possible (although very unlikely) result of climate change is a much more severe situation resulting in a Venus like situation (although not as high as temp and not as much nasty stuff in the atmosphere). If that happens, Mars will be much easier to survive on than Earth, since with a lot of energy from nuclear power, extremely cold environments are much more hospitable than extremely hot environments. Current models makes such a strong runaway result unlikely, but it is a possibility.
Is climate change seriously considered to be an existential risk? It seems to 1st order climate change would just move population densities, to 2nd order there might be net less or net more land and ag resources after the climate change, and either 2nd or 3rd order, the rate of hurricanes and other weather storms is changed.
It doesn’t seem to me that something which reduces human population from 6 billion to 2 billion should be considered an existential threat. A threat, yes, an expense we would prefer not to tolerate, perhaps. But a game ender? Not the way I play.
“On the Earth, the IPCC states that “a ‘runaway greenhouse effect’—analogous to Venus—appears to have virtually no chance of being induced by anthropogenic activities.” http://www.ipcc.ch/meetings/session31/inf3.pdf
Hmm, the IPCC asserts this statement without providing any argument to support it.
Some quick thoughts: In the beginning, there were no oceans. The earth was molten and without form. Now, assume venusian-runaway is a possibility for for this planet’s climate. Why has it not already occurred, much, much earlier in the planet’s history?
The planet was very much hotter and more humid in the very distant past. The CO2 in the oceans and the methane in the permafrost was captured from the atmosphere. The O2 in the atmosphere is a biogenic waste product of photosynthesis.
I do think the oceans will boil eventually, not because of global warming, but because of solar warming, after the sun has depleted it’s hydrogen.
My understanding is that all the Carbon which is fixed and stored under the ground in petroleum, coal, natural gas, and other “fossil” fuels was in the air of the earth as CO2 before it was fixed by plants and buried. So it would seem that even with ALL the fossil fuel carbon in the atmosphere, the earth supports life. Considering the adaptability of human life, especially with modern technology, I would be surprised if it was concluded that humanity would be wiped out by this.
The Mars colony could be useful to test the tools necessary to overcome the hostile climate, and it could make their development (possibly mass development) a higher priority.
So in case the Earth climate starts to change very rapidly, we would have a choice to use already developed and tested equipment, built in existing factories, instead of trying to invent it amidst global chaos.
If a Mars colony mitigates catastrophic risk (extinction risk?) from climate change,
then climate change is not an existential risk to human civilization on earth.
If humans can thrive on Mars, Earth based humanity will be able to cope with any climate change less drastic than transforming the climate of Earth to something as hostile as the current climate of Mars.
By the same logic,
Is not a good addition. The Mars-hardened facilities will be hardened only for Mars conditions (unless it’s extremely easy to harden against any level of radiation?) in order to cut colonization costs from ‘mindbogglingly expensive and equivalent to decades of world GDP’ to something more reasonable like ‘decade of world GDP’. So given a supernova, they will have to upgrade their facilities anyway and they are worse positioned than anyone on Earth: no ozone layer, no atmosphere in general, small resource & industrial base, etc. Any defense against supernova on Mars could be better done on Earth.
Good point. Mars would only be better off if the colonies over-engineered their radiation protection. Otherwise anything that gets through Earth’s natural protection would probably get through Martian settlements designed to give the same level of protection. It might be relatively cheap to over-engineer (e.g. digging in an extra meter), but it might not.
FWIW, while researching my Moore’s law essay, I found materials claiming that underground construction was more expensive but paid for itself via better heating/cooling. But that was for shallow cut-and-scrape constructions and I suspect 1 meter wouldn’t take care of supernova radiation.
As far as I understand the issue, the danger is mainly from the temporary ozone layer depletion, with the resulting solar UV rays doing most of the damage, and not from any kind of direct supernova radiation. And UV is not hard to shield from.
Hm, so you’re right: http://en.wikipedia.org/wiki/Near-Earth_supernova#Effects_on_Earth In that case, it doesn’t sound like that much of a direct threat at all: we can use cheap underground or UV-glass-filtering greenhouses to grow our food. A disaster, but not really an existential threat.
This does not follow. One possible (although very unlikely) result of climate change is a much more severe situation resulting in a Venus like situation (although not as high as temp and not as much nasty stuff in the atmosphere). If that happens, Mars will be much easier to survive on than Earth, since with a lot of energy from nuclear power, extremely cold environments are much more hospitable than extremely hot environments. Current models makes such a strong runaway result unlikely, but it is a possibility.
Is climate change seriously considered to be an existential risk? It seems to 1st order climate change would just move population densities, to 2nd order there might be net less or net more land and ag resources after the climate change, and either 2nd or 3rd order, the rate of hurricanes and other weather storms is changed.
It doesn’t seem to me that something which reduces human population from 6 billion to 2 billion should be considered an existential threat. A threat, yes, an expense we would prefer not to tolerate, perhaps. But a game ender? Not the way I play.
Runaway (“Venusian”) climate change is an existential risk, though most consider that a pretty unlikely scenario.
Hmm, the IPCC asserts this statement without providing any argument to support it.
Some quick thoughts: In the beginning, there were no oceans. The earth was molten and without form. Now, assume venusian-runaway is a possibility for for this planet’s climate. Why has it not already occurred, much, much earlier in the planet’s history?
The planet was very much hotter and more humid in the very distant past. The CO2 in the oceans and the methane in the permafrost was captured from the atmosphere. The O2 in the atmosphere is a biogenic waste product of photosynthesis.
I do think the oceans will boil eventually, not because of global warming, but because of solar warming, after the sun has depleted it’s hydrogen.
My understanding is that all the Carbon which is fixed and stored under the ground in petroleum, coal, natural gas, and other “fossil” fuels was in the air of the earth as CO2 before it was fixed by plants and buried. So it would seem that even with ALL the fossil fuel carbon in the atmosphere, the earth supports life. Considering the adaptability of human life, especially with modern technology, I would be surprised if it was concluded that humanity would be wiped out by this.
The Mars colony could be useful to test the tools necessary to overcome the hostile climate, and it could make their development (possibly mass development) a higher priority.
So in case the Earth climate starts to change very rapidly, we would have a choice to use already developed and tested equipment, built in existing factories, instead of trying to invent it amidst global chaos.