
Inventory of CO2 available for terraforming Mars - pmoriarty
https://www.nature.com/articles/s41550-018-0529-6
======
fallingfrog
I love the idea of colonizing Mars, on a purely romantic level. But on a more
practical level, let's compare Mars with Antarctica as candidates for large
human populations.

Mars: no oxygen, atmospheric pressure essentially zero

Antarctica: breathable, oxygenated air

Mars: maybe a little salty ice below the surface near the poles

Antarctica: Covered with freshwater ice

Mars: 34 million miles away across empty space

Antarctica: a few hundred miles away by boat

I mean, Antarctica, or the bottom of the sea, or the peak of Mount Everest all
_wipe the floor_ with Mars on every metric you can think of. And I know that
various people have suggested that Mars might be a useful second home for
humanity in case some event wipes us all out.. but really, if we get wiped out
it's going to be self-inflicted, and compared with the difficulty of setting
up a viable colony on Mars, the difficulty of sending a few nukes over there
is negligible. It just doesn't buy very much insurance. Sorry to be a downer
but this is pretty farfetched.

~~~
ryanmercer
>Mars: maybe a little salty ice below the surface near the poles

Erm, there's more than a million cubic kilometers of water ice in the poles
that's literally oceans worth, the liquid water below the poles is only of
interest for astrobiology.

>I mean, Antarctica, or the bottom of the sea, or the peak of Mount Everest
all wipe the floor with Mars on every metric you can think of.

Except Antarctica is on Earth. The point of colonizing an off-world body is so
that we can spread ourselves out.

Earth = eggs in one basket. A super volcano like Yellowstone could easily kill
90%+ of our species in the first year after an eruption and most of the other
animal (and plant) life. Big rocks have smashed into Earth before and will
again. A pandemic could easily spread across the planet in months decimating
population and launching us back into the stone age as you just lost most of
the people that knew how the power plants work, how medicine worked, how
making concrete worked, how growing crops in worthwhile quantities worked.

Mars isn't about gaining more resources, it's about giving humanity an extra
life.

~~~
darkmighty
If we're going to live in underground habitats on Mars for humanity-backup,
isn't it easier to just build underground habitats on Earth?

A few hundreds of meters down and the nuke risk is negligible. You can
stockpile enough for hundreds of years at ~0 shipping cost. You can set up
fortified ducts/purification systems to get oxygen from the surface -- with
backup allowing a small population to live long enough for the surface to get
tolerable.

Heck, even a full blown self-sustaining underground habitat doesn't seem out
of question, since there's water readily available, plenty of perhaps
geothermal or nuclear power power, and construction minerals. Destroying the
Mars habitat might not be too much more difficult comparing to destroying this
colony. If it has less than 10,000 or so colonists the US gov. or similar
might even have a chance of keeping its location in secrecy.

Sure it doesn't cover all possible scenarios, but in terms of backup a
conflict-resistant habitat here on Earth seems like the best bang for your
buck.

Welcome to Zion.

~~~
logfromblammo
In the long run, ensuring the continued survival of humanity is not
sufficient. We must also preserve our space-launch capabilities.

It's a lot more difficult to launch through a rock ceiling, radioactive
atmosphere, and a cloud of Kessler Syndrome fragments, from a gravity well 1G
deep, than it is to launch from the surface of a rock with barely any
atmosphere, a bare handful of satellites, in a well only 0.38G deep.

Also, bear in mind that you won't just be stockpiling food, but sufficient
biodiversity to reassemble a viable ecosystem, and sufficient industry and
education to preserve a viable economy. Otherwise, you still die when the
nutri-mat and atmo-pure machines finally break down.

It's certainly easier to dig a deep hole and build a bunker in it, but that
expense does not advance the end goal. It is merely insurance against a
temporary setback. You still need to establish a launch-capable society on
another planet, or everything dies anyway when the sun expands.

Then, after that happens, someone will still be around to say, "It would be
cheaper and easier to colonize and terraform _Venus_ than to send generation
ships every which way."....

~~~
ryanmercer
>and a cloud of Kessler Syndrome fragments

Ugh, don't get me started there. Musk wanting to do all these internet
satellites interests me but seriously gives me nightmares too in regards to
Kessler syndrome.

~~~
baq
Starlink's birds are, according to publicly available information, to be put
in a quicky decaying orbit.

~~~
logfromblammo
In the event of a nuclear war, as suggested by an ancestor post, someone will
almost certainly attempt to use anti-satellite missiles as part of their
first-strike protocol--especially against those satellites suspected of
providing early warning for ICBM launches. Same deal for radar tracking sites.
Blind the enemy. The enemy launches everything they have because they're
blind, and think your missiles are already incoming.

Maybe someone launches anti-ballistic-missile missiles, and scores a few hits.
Debris is spreading to all kinds of orbits. Kessler Syndrome will be the least
of our problems as the bombs fall, but it'll be a pain later, after the
fallout clears.

------
ryanmercer
>The only greenhouse gas present in high enough quantities on Mars to warm it
up is carbon dioxide

Annnnnnnnd that's why some plans call for manufacturing far more efficient
greenhouse gasses in situ. You can also Free the oxygen locked in the regolith
itself with enough energy (so enough time). You could hurl smaller comets and
asteroids at the planet to add to the atmosphere.

[http://www.pnas.org/content/98/5/2154](http://www.pnas.org/content/98/5/2154)
for an example of making other greenhouse gasses.

The polar caps alone have more than a million cubic kilometers of dry ice and
more than a million cubic kilometers of water ice, the regolith over the
entire planet is also lousy with both in varying concentrations which will
release as the planet thaws.

When we actually have the technology abilities to influence the Martian
atmosphere in any appreciable quantity, eventually getting the atmosphere up
to a decent pressure will be more than doable given the interest.

Remember, just few decades ago we didn't even think Mars had water and now we
know there's more than a million cubic kilometers of water ice (and there's
something like 50,669,625,000,000,000 gallons/191,805,395,565,860,992 liters
of water in the caps alone).

The real problem with ever properly terraforming Mars is the nitrogen which
still isn't that big of an issue as again you can import it from comets and
asteroids or heat silicate to release nitrogen.

Hell we could get to Mars, dig a 5ft hole and go "woah! There's all kinds of
organic material down here, this must have been an ancient ocean teeming with
life!" and have all sorts of usable stuff for terraforming frozen in thick
layers of permafrost.

~~~
tomerico
Using low units (liters) so that the numbers look big, can be misleading. To
put it in perspective: The CO2 mass in the polar ice caps is 1/5000 of the
mass of earth atmosphere The water mass underneath is 1/4 of the volume of
water in the mediterranean sea.

~~~
ryanmercer
>The water mass underneath is 1/4 of the volume of water in the mediterranean
sea.

And Mars has about 38% the surface area of Earth, roughly the surface area of
all the dry land on Earth. For Mars that's a hell of a lot of water.

>The CO2 mass in the polar ice caps is 1/5000 of the mass of earth atmosphere

Which is more than enough to sustain above freezing temperatures when melted.
Add in what is frozen in the regolith all over the planet as permafrost and
you're well on your way to a pressure humans can survive without pressure
suits. Which allows you to start bringing in comets/asteroids as well as
heating various rocks to release various gasses as energy generation allows.

It makes terraforming quite doable for even our current civilization and if we
crack affordable fusion (we almost certainly will, probably in our lifetimes
assuming middle age or younger now) energy generation becomes a non-issue and
then it's just a matter of setting up shop on Mars, again with largely (if not
entirely) automated facilities that start chugging away generating 'designer'
greenhouse gasses to start the runaway greenhouse effect to melt the caps.

~~~
SolarNet
The Mediterranean Sea was/is not enough water for each of the human
civilizations that has ever lived on it's borders. Let alone the entire
(habitable area of the) planet.

------
lxmorj
Step 1: Go to Ceres

Step 2: Build Very Large Railgun™

Step 3: Make Ice Block Harvesting Robots

Step 4: Fire railgun for approximately a crapload of years, changing Ceres'
orbit to collide with Mars.

If you get the math Really Quite Spot On, you may be able to slow Ceres while
putting the ice projectiles on a highly elliptical orbit that will also hit
Mars. Get the final collision right as well, and you could spin up Mars a bit
(closer to 24hr days, though I think I'd like 28 better TBH), or slow it's
orbit down a bit.

It'd probably take a couple centuries, and the cool down period might take the
same, but when you're done you've got loads of water, a touch more mass, and a
great little bootstrapped planet.

~~~
dvasdekis
Why would you need to build a railgun? Nuking Ceres a bunch of times at the
correct angle should achieve the same thing.

But - there's a non-zero chance that this collision, whether by railgun or
nuke, endangers life on earth. Problematic, but I love the idea otherwise.

------
dperfect
Even if there was enough carbon dioxide, is seems likely that solar wind would
erode away any terraformed atmosphere as some believe happened in the past[1]
due to the lack of shielding from a global magnetic field.

[1]
[https://en.wikipedia.org/wiki/Atmosphere_of_Mars#History](https://en.wikipedia.org/wiki/Atmosphere_of_Mars#History)

~~~
ryanmercer
>Even if there was enough carbon dioxide, is seems likely that solar wind
would erode away any terraformed atmosphere as some believe happened in the
past

It will. Over MILLIONS of years. That happened on a geological time scale.
People clutch to this claiming 'the solar wind will blow it away' but fail to
realize how long this process takes.

~~~
dperfect
Thanks. That's true, though to be fair, the kind of changes needed to
terraform Mars also normally happen on geological time scales. That's not to
say it can't be done faster, but as others have mentioned, plans to terraform
the planet are incomplete if they don't address the issue of solar wind.

~~~
ryanmercer
>the kind of changes needed to terraform Mars also normally happen on
geological time scales.

Not when humans are involved. All you need to do is raise the average
temperature 5C to create a runaway greenhouse effect on Mars. While that's
more than we've done on Earth, what we've done here was entirely on accident.

With an actual effort... we could probably do that in a few decades with
technology not much more advanced than what we have now. Just doing something
like the Russian Znamya project (orbital mirrors), and a little bit of seeding
the polar regions with carbon to help absorb sunlight, we could bathe the caps
in sunlight 24:37 687 days a year. That combined with creation of 'designer'
artificial greenhouse gasses could get you to the runaway process quicker than
the natural human lifespan and if you kept generating your own greenhouse
gasses/reflecting light to the surface/importing smaller comets (smaller so
you're burning the bulk up in the slowly thickening atmosphere instead of
impacting and throwing up dust), you could get it there in a few centuries and
have the process largely, if not entirely, automated.

------
24gttghh
Could anyone comment feasibility on the 'Cowboy Bebop'-style para-terraforming
postulated on Mars by creating a small non-domed, livable section inside of a
large crater, where the crater walls are high enough to 'contain' enough of
the greenhouse gases being produced by the settlements? [0] Would we be better
off just building huge domes, or digging underground?

[0][https://i1.wp.com/www.inetres.com/gp/anime/bebop/02/bebop_02...](https://i1.wp.com/www.inetres.com/gp/anime/bebop/02/bebop_02_04.jpg)

~~~
scardine
Not exactly this one but you could dig moholes. I guess a mohole deep enough
to get you 1 atm would be too hot for humans but I will not even try to do the
math.

------
maerF0x0
it strikes me that the terraforming goal is often expressed to be habitable to
humans... Why not some economic middle ground? For example, if the oxygen was
sufficient for me to survive ~1hour, it would add a bunch of safety in case of
ripped suit etc. In many areas of life these middle grounds are much
easier/faster to accomplish than the "pure" solution. Maybe that concept
applies to colonies on mars too?

~~~
kanox
One decent "middle ground" would be if you could step outside using just an
oxygen mask instead of a full spacesuit. Unfortunately the conclusion of this
paper is that there isn't nearly enough CO2 to reach the required pressure.

------
jchin
Title reminded me of this board game called Terraforming Mars:
[https://boardgamegeek.com/boardgame/167791/terraforming-
mars](https://boardgamegeek.com/boardgame/167791/terraforming-mars)

For me, each play-through has taken hours but after finally playing it
correctly (first two times I played I misinterpreted some crucial rules), I
enjoyed the game quite a bit.

~~~
adamredwoods
I'm curious how much scientific research they did for the cards.

------
logfromblammo
... by relying on the greenhouse effect from carbon dioxide.

And you wouldn't want to do that, anyway, since it would result in a carbon
dioxide concentration too high for an eventually breathable atmosphere. What
you really want there is water vapor and perfluorocarbons.

But cranking those out takes time. Mars might be warm in 1000 years.

Still, shorter than the trip to another star.

------
chris_va
I was curious about the potential for other compounds. SF6, per molecule is
about 22,000x better than CO2: [https://whatsyourimpact.org/high-global-
warming-potential-ga...](https://whatsyourimpact.org/high-global-warming-
potential-gases)

And there is a seemingly nice paper here on the potential for designer gas
mixes:
[http://www.pnas.org/content/pnas/98/5/2154.full.pdf](http://www.pnas.org/content/pnas/98/5/2154.full.pdf)

------
kraig911
Would it be impractical to just send a bunch of large asteroids to collide
with Mars to get the minerals and gases we need?

~~~
ryanmercer
Impractical? That just depends on what resources you have to tackle the
problem with.

Identifying candidate comets and asteroids is the first step, then coming up
with some sort of propulsion system is the next step. You won't need a lot of
thrust at once, you'll just need continuous thrust for weeks, months or even
years. Nudge the body into an intercept with Mars and wait. Could easily take
decades (if not longer) to start impacting depending on where in the system
you are shopping.

Good news is, comets and asteroids already come reeeeeallllllly close to the
rocky planets so it's just a matter of meeting them far enough out and
applying just the right amount of thrust.

Bad news is, if your math isn't right... whoops you just put something on a
collision course with Earth BUT you'd detect this WAYYYYYY before it would
happen and you'd just apply more thrust, unless of course something happened
to your propulsion system so you'd absolutely want something out there that
could move fast enough to intercept, land, apply thrust.

Impacting won't do much though to raise temperature or atmosphere, the
atmosphere is thin enough you won't burn up much right now so you'd still need
to thicken the atmosphere up some another way.

~~~
kraig911
Actually found an interesting article about this. Sounds like it's just more
of an energy expense with a small amount of benefit.

[https://space.stackexchange.com/questions/16898/what-
would-b...](https://space.stackexchange.com/questions/16898/what-would-be-the-
effect-of-increasing-the-mass-of-mars)

~~~
unchocked
That link discusses bringing mass to Mars to increase its gravity.

This conversation is about bringing gas to Mars to thicken its atmosphere.

They’re very different ideas, and the second one is a lot more interesting
than the first.

~~~
ryanmercer
Easiest way to increase the atmosphere would be to add material though, in
this case comets and asteroids that had significant amounts of ices (and
hopefully lots of metals, even meteoric iron would be extremely valuable on
Mars as a source of easy to process metal).

------
creaghpatr
Not with that attitude.

~~~
394549
Attitude doesn't trump facts or reality.

~~~
Yetanfou
If $deity wanted man to fly he would have given him wings.

(enter Montgolfier, Lilienthal, Santos-Dumont, the Wright brothers, etc)

Flying faster than the speed of sound is impossible, there is a wall out there
which will crush any plane trying to break through it.

(enter Lippisch, those British researchers who realised a moving tail can keep
a plane stable across the sound barrier but for some reason were not allowed
to test their ideas in practice, Bell Aerospace and Chuck Yeager)

Notice the pattern?

~~~
394549
> Notice the pattern?

No.

For ages, people have sought to convert lead to gold though alchemy. Some
skeptics said that was impossible or uneconomical.

(Enter... no one)

Turns out the skeptics are right and no amount of positive attitude and can-do
spirit can change that fact.

Terraforming Mars is a lot closer to alchemy than powered flight, if the
literal matter needed does not already exist on Mars. If we have the
technology for space-tugs that can transport an atmosphere's worth of matter
to it, I doubt we'd still be interested in the project.

~~~
Yetanfou
Transforming lead to gold is possible, it takes a particle accelerator and a
lot of energy but it can be done. It has been done in 1980 at Lawrence
Berkeley National Laboratory (LBNL) in California [1] although they started
with bismuth instead of lead.

Arthur C. Clarke had the following to say on the subject:

1: When a distinguished but elderly scientist states that something is
possible, he is almost certainly right. When he states that something is
impossible, he is very probably wrong.

2: The only way of discovering the limits of the possible is to venture a
little way past them into the impossible.

3: Any sufficiently advanced technology is indistinguishable from magic.

While terraforming Mars is certainly a daunting prospect the single fact that
there is not enough CO2 to create enough of a greenhouse effect to warm the
planet does not seem enough of a reason for me to give up on the prospect.
There are more effective greenhouse gases than CO2, methane comes to mind.
What is not readily present on Mars can be 'liberated' from it chemical bonds
or deposited there by means of inbound objects rich in the required substance.

[1] [https://www.scientificamerican.com/article/fact-or-
fiction-l...](https://www.scientificamerican.com/article/fact-or-fiction-lead-
can-be-turned-into-gold/)

[2]
[https://en.wikipedia.org/wiki/Clarke%27s_three_laws](https://en.wikipedia.org/wiki/Clarke%27s_three_laws)

~~~
394549
>> For ages, people have sought to convert lead to gold though alchemy. Some
skeptics said that was impossible or _uneconomical_.

> Transforming lead to gold is possible, it takes a particle accelerator and a
> lot of energy but it can be done. It has been done in 1980 at Lawrence
> Berkeley National Laboratory (LBNL) in California [1] although they started
> with bismuth instead of lead.

I know that (see emphasis above). The process you cite is _utterly_
uneconomical. It is impossible to transform lead to gold in _all_ practical
senses.

> What is not readily present on Mars can be 'liberated' from it chemical
> bonds or deposited there by means of inbound objects rich in the required
> substance.

Again, the technology and resources required to transport an atmosphere's
worth of matter to Mars likely have far more beneficial uses that a
terraforming project, such as the construction and provisioning of large
habitable space stations.

------
ohitsdom
> Plans to do so have included dropping thermonuclear weapons at the planet's
> poles – an idea supported by Elon Musk.

This is misleading at best. Elon hasn't endorsed one way of terraforming Mars.
He has said it's a question best left to Mars settlers.

------
a008t
Would it not be easier to build and maintain a space station in a stable
Lagrangian point? Gerard O'Neill described a roadmap to one in 1976 in
[https://en.wikipedia.org/wiki/The_High_Frontier:_Human_Colon...](https://en.wikipedia.org/wiki/The_High_Frontier:_Human_Colonies_in_Space)

The ideas were brought to life in Hideo Kojima's Policenauts, which is an
interesting, rather detailed illustration of how the whole thing might work
out. Somehow, I find the idea of a space station like that more exciting than
the idea of colonizing Mars.

------
linuxftw
The amount of capital required (both human and material) is too large to
achieve colonizing Mars, even in a small capacity. It's a pipe dream, never
going to happen without some science-fiction physics-bending solution
(teleporting, free energy, etc).

Let's spend those countless billions on improving conditions here.

~~~
eigenloss
> The amount of capital required (both human and material) is too large to
> achieve colonizing Mars, even in a small capacity.

Sending people to Mars would cost a few times as much as the construction
(inflation adjusted) of the US interstate highway system. [1] There is a
reason physicists, economists, and engineers, but usually not Linux container
experts, are consulted when evaluating megaproject proposals.

> Let's spend those countless billions on improving conditions here.

How do you propose we allocate those billions? Who do you delegate to allocate
those billions? Is the marginal benefit of that reallocation greater than the
marginal cost of killing off all interplanetary colonization efforts?

[1] [https://spacenews.com/op-ed-mars-for-
only-1-5-trillion/](https://spacenews.com/op-ed-mars-for-only-1-5-trillion/)

~~~
linuxftw
> How do you propose we allocate those billions?

I propose we don't collect the billions in the first place.

> Sending people to Mars would cost a few times as much as the construction
> (inflation adjusted) of the US interstate highway system. [1]

Sending a few people and even establishing some kind of 'base' is not the same
as colonizing. That's just the cost of getting 9 crews there and back. If the
article is implying Apollo-sized crews, that's not very many people.

Heavy machinery, concrete, steel/aluminum, fuel, everything needed to create
structures. The costs will be innumerable, and for what benefit? So
potentially a select few people get to fly to Mars and live there?

------
rebelde
A heartfelt discussion about terraforming Mars. This is HN at its most
entertaining. I'm serious. Thank you!

------
cabaalis
Reading through this led me to also Google the unrelated issue of estimates of
how long fossil fuels will last at current pace. I'd never thought about that
before, and I am actually now concerned about my child's future. (Which of
course I worry about other things, but is a first for that aspect.)

Without a major shift in energy source, soon, we will never be able to leave
our planet. Humanity will end here.

~~~
windows_tips
A long time. With uranium, ground-fuels will last even longer.

Sun's supposed to explode and consume the planet soon though.

------
senectus1
pfft, Why bother. I reckon the first serious population on mars will be miners
and industrialists.

They'll mine the crap out of it, setup horribly polluting industry and makes
shit to sell elsewhere.

------
solresident
idk why you can't just grind up a shit-ton of plastic and create sand-plastic
electrostatic differential on the surface to produce more green house gases,
ch4

------
natch
Judging by the abstract, they set aside and don't even consider the question
of whether we could change humans to meet Mars halfway.

------
baybal2
Lets not be too optimistic.

The biggest problem for mars is not pressure, but nitrogen.

You can make oxygen from CO2, obviously. But where do you get nitrogen?

------
Robotbeat
This article is essentially an opinion article. It is paywalled, and the
Abstract contains no actual quantitative data on which to judge the contents.
It uses "today's technology" as some sort of viability deteriminant, but this
is really kind of tautological: we haven't really perfected the art of sending
large payloads to Mars, yet. We struggle to do about one ton. So _of course_
current technology is insufficient.

They speak of CO2 greenhouse effect not being sufficient to cause sufficient
warming... But that's kind of obvious, isn't it? Because if it was sufficient
with easily accessible reservoirs, that'd imply Mars is in some sort of
unequilibrium state that could randomly trigger into a partial runaway
greenhouse effect (to terraform the planet, not make it like Venus) without
even our intervention.

And another thing, warmth is fairly easy to address. What's critical is
_pressure_. I'm much less interested in the amount of CO2 to heat the whole
planet by itself than I am in the amount of CO2 needed to exceed the Armstrong
Limit (0.9psi, the minimum pressure you can survive without a pressure suit
and only a forced air oxygen mask) at the lowest points on Mars (like Hellas
Basin). That's not addressed in the abstract at all, and I'm not about to pay
for an article that doesn't even bother to answer such a basic question in the
abstract as what _mass_ of CO2 exists in these reservoirs (from which one can
easily determine the pressure... Mars needs about 6e16kg of additional
volatiles added to its atmosphere to reach the Armstrong Limit in Hellas
Basin... Mars' atmosphere is currently 2.5e16kg).

Every terraforming proposal I've seen does something like this:

1) Increase albedo of surface via dust on the poles or black powder.

2) Increase greenhouse effect by industrial production of super greenhouse
gases that are far more effective (>20,000?) than CO2.

3) Increase insolation of Mars via giant orbital mirrors (more realistic than
you might think, as you can use micron-thick solar sail type material).

4) Adding more volatiles from exterior sources like comets or asteroids or
moons.

5) Vaporize very deep reservoirs of volatiles using fission or fusion or
geothermal or sunlight or impact energy, reservoirs not considered here.

Many of these require "new" technology, but the principles behind each one are
pretty well understood.

...it's simply impossible to have a serious discussion of this paper as it's
paywalled and contains no quantitative information in the public abstract.
Instead, it serves as just a conversation piece for what people already think
about Mars terraforming.

------
lainga
And yet again, there isn't a single link to the paper anywhere in the article.
A pop-up autoplaying video doesn't replace good journalism.

[https://www.nature.com/articles/s41550-018-0529-6](https://www.nature.com/articles/s41550-018-0529-6)

~~~
bargl
This is a much better article. The current one is just click-bait. I'm glad I
read it but I'm even more glad it was with the context of other comments on
HN.

~~~
geoalchimista
That is because Nature Perspectives are written by real scientists for a wider
audience than their niche. Not only are those articles scientifically more
accurate, but the writers usually try to engage in a dialogue with the
readers, which you don't often see in today's journalism.

