We just don't have the technology at present. So not really much point in trying to guess costs.
Mars society estimate a 1000 year long program. That's not including oxygen. It's just a tree and plants friendly planet - if it worked, humans would use oxygen masks, and you wouldn't have animals or birds yet. They estimate an oxygen rich atmosphere as another several millennia (Chris McKay estimates an extra 100,000 years for an oxygen rich atmosphere).
That includes sending mirrors into space around Mars - one of the issues is that it's further from the sun so doesn't have Earth levels of sunshine. So they build giant space mirrors to double the amount of light received by the planet. Another idea, probably do both, is to build factories on Mars to generate greenhouse gases.
But this shouldn't be taken as a prediction or more than a rough guess, after feeding in optimistic figures and projections.
We haven't terraformed any planets and don't understand Earth's climate too well - see how much debate there is about whether or not we are warming it by adding CO2.
We only have a few centuries of reliable data on Earth's climate.
We haven't yet achieved a closed system habitat the size of Biosphere 2.
And - on Earth - the same process took hundreds of millions of years to complete. You might look at the regular changes in the oxygen concentration
There is also lots to go wrong along the way. It could end up in a worse state than it is now for humans, and changed so that it is hard to attempt to terraform again.
And if it succeeds, if it is really true that you can change the climate of an entire planet from a vacuum covered dry cold planet like Mars to one with a thick oxygen rich atmosphere like Earth, as quickly as a thousand years - what's to stop it from unterraforming as quickly as it terraformed?
Also - how do we know that whatever civilization there is a thousand years from now will want this? Even a few decades from now, chances are that we have other priorities and new ideas of what's the best megatechnology project to take on in our solar system - if we do any at all.
And what other technological project have humans taken on that lasted - in modern times even for longer than a few decades? In the past some constructions of buildings,have taken centuries, don't know of anything that took millennia to complete.
I think terraforming, if we do it at all, is a technology for a future century or at least a hugely increased understanding over what we have now.
Indeed, I think we are too young as a civilization to undertake any projects that can only be completed on a multi-century or multi-millennia timescale - and need to be sustained for that long to be successful.
And I think we need to think carefully about the unexpected long term effects of the shorter term projects we do take on.
Though building large self enclosed "Biosphere 2" type habitats in space - that we could do in the near future. That's a multi-decade project, rather than a multi-millennium project, and also can be approached incrementally, with smaller habitats and habitats that are almost closed system.
Terraforming though - that we can't approach incrementally, it's an all or nothing thing. Once you start to terraform a planet you are committed to finish the job or you are pretty sure to leave it worse off than you started (warmed up, volatiles escape, but then cools down again, ice covers the planet and it goes into a snowball deep freeze, introduced life, can't remove it, or it puts the planet into unexpected end states etc etc).
But thinking about ideas for terraforming - that I think is beneficial, helps us to look at the Earth in a different way - probably also help us to understand explanets better - the discipline of looking into ways of terraforming worlds I think is beneficial - just think - applying it - that's what we aren't ready for yet.
See
Trouble With Terraforming Mars
Imagined Colours Of Future Mars - What Happens If We Treat A Planet As A Giant Petri Dish?
Mars society estimate a 1000 year long program. That's not including oxygen. It's just a tree and plants friendly planet - if it worked, humans would use oxygen masks, and you wouldn't have animals or birds yet. They estimate an oxygen rich atmosphere as another several millennia (Chris McKay estimates an extra 100,000 years for an oxygen rich atmosphere).
That includes sending mirrors into space around Mars - one of the issues is that it's further from the sun so doesn't have Earth levels of sunshine. So they build giant space mirrors to double the amount of light received by the planet. Another idea, probably do both, is to build factories on Mars to generate greenhouse gases.
But this shouldn't be taken as a prediction or more than a rough guess, after feeding in optimistic figures and projections.
We haven't terraformed any planets and don't understand Earth's climate too well - see how much debate there is about whether or not we are warming it by adding CO2.
We only have a few centuries of reliable data on Earth's climate.
We haven't yet achieved a closed system habitat the size of Biosphere 2.
And - on Earth - the same process took hundreds of millions of years to complete. You might look at the regular changes in the oxygen concentration
There is also lots to go wrong along the way. It could end up in a worse state than it is now for humans, and changed so that it is hard to attempt to terraform again.
And if it succeeds, if it is really true that you can change the climate of an entire planet from a vacuum covered dry cold planet like Mars to one with a thick oxygen rich atmosphere like Earth, as quickly as a thousand years - what's to stop it from unterraforming as quickly as it terraformed?
Also - how do we know that whatever civilization there is a thousand years from now will want this? Even a few decades from now, chances are that we have other priorities and new ideas of what's the best megatechnology project to take on in our solar system - if we do any at all.
And what other technological project have humans taken on that lasted - in modern times even for longer than a few decades? In the past some constructions of buildings,have taken centuries, don't know of anything that took millennia to complete.
I think terraforming, if we do it at all, is a technology for a future century or at least a hugely increased understanding over what we have now.
Indeed, I think we are too young as a civilization to undertake any projects that can only be completed on a multi-century or multi-millennia timescale - and need to be sustained for that long to be successful.
And I think we need to think carefully about the unexpected long term effects of the shorter term projects we do take on.
Though building large self enclosed "Biosphere 2" type habitats in space - that we could do in the near future. That's a multi-decade project, rather than a multi-millennium project, and also can be approached incrementally, with smaller habitats and habitats that are almost closed system.
Terraforming though - that we can't approach incrementally, it's an all or nothing thing. Once you start to terraform a planet you are committed to finish the job or you are pretty sure to leave it worse off than you started (warmed up, volatiles escape, but then cools down again, ice covers the planet and it goes into a snowball deep freeze, introduced life, can't remove it, or it puts the planet into unexpected end states etc etc).
But thinking about ideas for terraforming - that I think is beneficial, helps us to look at the Earth in a different way - probably also help us to understand explanets better - the discipline of looking into ways of terraforming worlds I think is beneficial - just think - applying it - that's what we aren't ready for yet.
See
Trouble With Terraforming Mars
Imagined Colours Of Future Mars - What Happens If We Treat A Planet As A Giant Petri Dish?
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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