
Cooling the Earth with a cloud of small spacecraft near the inner Lagrange point - abecedarius
http://www.pnas.org/content/103/46/17184.full
======
mchannon
This strategy, to get rid of some sunlight, doesn't fix our problem with CO2.
In fact, it's likely to make the problem worse.

Our planet has two primary natural methods for lowering atmospheric CO2. One,
natural weathering, is not impacted with this strategy.

The other, plantlife, is absolutely affected. If you were to take 10% of
sunlight away from Earth, then it logically follows that plants would get 10%
less sunlight to convert CO2 into starches and H2O into oxygen. The resource
you're trying to constrain, in the name of fighting effects of rising CO2
levels, is the very resource you need in order to fight rising CO2 levels.

Sure, blocking or deflecting some light might lower Earth's temperatures
temporarily, but you'd exacerbate CO2 levels semi-permanently.

We, as a community, need to come to the realization that our CO2 problem is
not strictly a temperature problem.

~~~
hwillis
Every idea for geoengineering as a solution to climate change is _insane_.
They're either nonsense, like solar chimneys, or they're like this one: way
worse than the problem currently is, and WAY worse than _not emitting CO2_
would be. Take atmospheric sulfate aerosols[1], which I often see touted as
the solution, usually by conspiracy theorists. The kind of people who think
"big green energy" is money play, and this simple solution is being hidden for
some grand reason.

"Atmospheric sulfate aerosols" means _spraying sulfuric acid into the air_.
It's all the joy of this solution with the added bonus of primarily blocking
visible light, destroying the ozone layer, and scattering light so that solar
panels and plant life don't work as well. Oh yeah, and SPRAYING ACID INTO THE
AIR. Intentional acid rain, forever. It's an incredibly foolish, destructive
idea that people with zero drive to do basic research support vocally.

The cheapest, easiest and safest way to fight climate change is to stop
emitting CO2. It would be so incredibly easy to stop 80% of anthropogenic
emissions. These geoengineering plans are worse in every way.

[1]:
[https://en.wikipedia.org/wiki/Stratospheric_sulfur_aerosols](https://en.wikipedia.org/wiki/Stratospheric_sulfur_aerosols)

~~~
jseliger
_The cheapest, easiest and safest way to fight climate change is to stop
emitting CO2_

Which is absolutely true, but no one (basically) is doing it. And the U.S. is
moving in the right direction in some metrics (solar, wind) but the wrong in
many others (urban planning ([https://www.vox.com/energy-and-
environment/2017/8/22/1617782...](https://www.vox.com/energy-and-
environment/2017/8/22/16177820/california-transportation)), nuclear
([https://www.technologyreview.com/s/603647/meltdown-of-
toshib...](https://www.technologyreview.com/s/603647/meltdown-of-toshibas-
nuclear-business-dooms-new-construction-in-the-us/)), and politics (Trump,
Cruz, etc.)).

So while I agree with the proposed solution, no one else does, and even then
we have to deal with China and India joining the developed world and what that
means for CO2 emissions.

~~~
hwillis
>even then we have to deal with China and India joining the developed world
and what that means for CO2 emissions.

Evidence disagrees. Chinese coal consumption is declining ever so gradually
(~1% annually) despite their economy growing as normal. In fact their overall
co2 emissions are slowly falling as well. Its an open question whether this is
going to continue or if this is just a false peak, but if their commitment to
renewable and green energy is a predictor then they may fall below the us
emission level relatively soon.

~~~
enraged_camel
Serious question: how reliable are the figures from China? How can we trust
they aren't fudging the numbers, either at the local level or the national
level?

~~~
askmike
What is there to gain from fudging these numbers?

~~~
Rescis
Continued economic growth at the increased rates that non-renewable energy
sources provide, without the external disapproval/sanctions that come with
them.

------
patrickdavey
I'd argue that the more energy you use, the more comfortable your life is.

I'd also argue that energy use (at the moment) is pretty linked to how much
CO2 you emit.

A lot of the biggest emitters live in democracies.

So, how do you get the majority of the population to vote in politicians who
are going to make their lives less comfortable (by taxing / controlling /
lessening the amount of CO2 they use)?

Frankly I reckon we, as a civilization, are going to dither and procrastinate
up until the point it's far far far too late to do anything meaningful, and
then people will try jump on the geoengineering to hack things into place.
There was a nice piece in the book "This changes everything" where they were
talking about geoengineering. I'll paraphrase, but basically someone said
"we'll just alter things in this way", and someone else said "that'll mean
droughts in my country". Fun times ahead.

If you haven't read it yet, I recommend "Sustainable Energy Without the Hot
Air" [0] to get an idea of just how much less energy we need to use if we want
to get by with just renewables. I really hope we can get there!

[0] [https://www.withouthotair.com/](https://www.withouthotair.com/)

------
philipkglass
_If it were to become apparent that dangerous changes in global climate were
inevitable, despite greenhouse gas controls, active methods to cool the Earth
on an emergency basis might be desirable. ... It seems feasible that it could
be developed and deployed in ≈25 years at a cost of a few trillion dollars,
<0.5% of world gross domestic product (GDP) over that time._

The "few trillion dollars" part is a problem. Not because it represents a
particularly high cost scheme for neutralizing the warming part of AGW, but
because it's so all-or-nothing. If you invest "only" $10 billion in this
scheme the marginal abatement effects are going to be pretty close to zero,
because so much of the cost is front-loaded into enabling technologies that
will _eventually_ deliver direct benefits.

I refer the interested reader to the classic The Political Economy of Very
Large Space Projects:

[http://www.jetpress.org/volume4/space.htm](http://www.jetpress.org/volume4/space.htm)

With minor adjustments, it could be generalized as The Political Economy of
Very Large Projects.

~~~
kanzure
> The "few trillion dollars" part is a problem.

I am not particularly convinced that this requires a few trillion dollars. Is
there some hard evidence that sunshades are impossible to deploy with less
than $10 billion?

[http://diyhpl.us/~bryan/papers2/space/Self-
deployed%20extrem...](http://diyhpl.us/~bryan/papers2/space/Self-
deployed%20extremely%20large%20low%20mass%20space%20structures%20-%202007.pdf)

------
godshatter
I'm not against geo-engineering as a general concept, even though I don't
personally buy into the most alarmist of the climate change scenarios. If we
do do some kind of project like this, I would want to have a counter in place
in case it does more harm than good, as a general rule of thumb. I would want
that factored into the cost and preparations in place for just such an
eventuality before committing to such a course.

In this case, though, it seems relatively trivial - it seems like it's more
work to keep them in place then to have them scatter to the (solar?) winds.
Once they've moved out of the Lagrange point, then they become a non-issue.
All we've lost is the money to put them there and the materials. Compared to
some of the other ideas I've heard, this appears to be much safer.

------
bmcusick
If you're going to put 20 million tons of perfectly identical gram-sized craft
into orbit somewhere, it seems a lot more sensible to launch a factory to the
Moon rather than launch all that mass from Earth. The CO2 added to the
atmosphere from burning 2 billion tons of rocket fuel cannot be negligible.

~~~
sp332
This is addressed in the paper. It's even addressed in the abstract of the
paper.

Edit: _Second is a concept aimed at reducing transportation cost to $50 /kg by
using electromagnetic acceleration to escape Earth's gravity, followed by ion
propulsion._ The paper says that if there are rockets involved, they will be
used outside of the atmosphere.

~~~
robotresearcher
> It's even addressed in the abstract of the paper.

Where?

edit: located below (italics added) thanks. The environmental costs of launch
are considered. I can't see the environmental impact of _manufacture_
considered explicitly, though.

Abstract:

If it were to become apparent that dangerous changes in global climate were
inevitable, despite greenhouse gas controls, active methods to cool the Earth
on an emergency basis might be desirable. The concept considered here is to
block 1.8% of the solar flux with a space sunshade orbited near the inner
Lagrange point (L1), in-line between the Earth and sun. Following the work of
J. Early [Early, JT (1989) J Br Interplanet Soc 42:567–569], transparent
material would be used to deflect the sunlight, rather than to absorb it, to
minimize the shift in balance out from L1 caused by radiation pressure. Three
advances aimed at practical implementation are presented. First is an optical
design for a very thin refractive screen with low reflectivity, leading to a
total sunshade mass of ≈20 million tons. _Second is a concept aimed at
reducing transportation cost to $50 /kg by using electromagnetic acceleration
to escape Earth's gravity, followed by ion propulsion_. Third is an
implementation of the sunshade as a cloud of many spacecraft, autonomously
stabilized by modulating solar radiation pressure. These meter-sized “flyers”
would be assembled completely before launch, avoiding any need for
construction or unfolding in space. They would weigh a gram each, be launched
in stacks of 800,000, and remain for a projected lifetime of 50 years within a
100,000-km-long cloud. The concept builds on existing technologies. It seems
feasible that it could be developed and deployed in ≈25 years at a cost of a
few trillion dollars, <0.5% of world gross domestic product (GDP) over that
time.

~~~
Footkerchief
The issue being addressed:

> The CO2 added to the atmosphere from burning 2 billion tons of rocket fuel
> cannot be negligible.

The quote from the abstract that addresses it:

> Second is a concept aimed at reducing transportation cost to $50/kg by using
> electromagnetic acceleration to escape Earth's gravity, followed by ion
> propulsion.

More detail later in the paper:

> Because of its enormous area and the mass required, shading from space has
> in the past been regarded as requiring manufacture in space from lunar or
> asteroid material and, thus, as rather futuristic. Here we explore
> quantitatively an approach aimed at a relatively near-term solution in which
> the sunshade would be manufactured completely and launched from Earth, and
> it would take the form of many small autonomous spacecraft (“flyers”).

------
idbehold
Since stopping CO2 levels from rising is nigh impossible, the only option left
it seems is something drastic like this (I'm reminded of Futurama where they
drop a giant ice cube into the ocean every once in a while). It has the added
benefit of being able to be done without depending on everyone else changing
their habits.

I have a feeling that there are a bunch of these "plan B" solutions to our
global climate change problem. It's that they are mostly just giving us more
time before we have to actually deal with the problem. If the Atlantic
Meridional Overturning Circulation ever comes to a halt then we are really
screwed, so if there's anything which could prevent that from happening it
might be worth the risk.

~~~
archagon
The problem with geo-engineering solutions to global warming is that they
would require global consent. Anything else would be a drastic violation of
human rights, and potentially a cause for massive conflict. We all have to
share the same planet, and some peoples might be drastically opposed to
(potentially) irreversible processes such as the scattering of chemicals in
the atmosphere. Any "for the good of mankind" justification is almost beside
the point.

~~~
idbehold
Wait, so everyone is allowed to contribute to global climate change without
permission, but we need everyone's agreement to prevent it?

~~~
archagon
Unfortunately, yes? Nobody made the decision to contribute to global climate
change; it just kind of happened as an emergent consequence of the discovery
of oil. Whereas a single country deciding to permanently tint the sky is not
going to go over well with the global community, probably to the point of
tanks on borders and missiles at ready.

~~~
cortesoft
It wouldn't require global consent, just consent of the few global powers
strong enough to do anything about it.

~~~
archagon
Sure, but I think it'll be very difficult to get the US, China, and Russia to
agree on something as drastic as this before catastrophic climate-related
events start taking place. (And let's not forget all the other nations with
nuclear missiles. The playing field is a lot more level these days, for better
or worse.)

~~~
adrianN
Luckily(?) catastrophic climate-related events are already happening.

------
gdubs
I'm all for exploring solutions, but I also wonder about the behavioral
economics at play when people "feel" like a geo-engineering solution is
inevitable.

In other words, how much does believing we will inevitably engineer our way
out of the problem keep us from making the hard choices that may be necessary.

~~~
fleitz
All solutions are geo-engineering...

Exactly what kind of solution are all the things that are recommended to do to
lower global CO2?

The only difference is the current recommendations are inefficient and take a
long time.

~~~
andai
And are at odds with greed / desire for comfort and luxury.

~~~
fleitz
Exactly, which is why the whole thing is stupid and isn't going to happen.

Enviros: You can enjoy longer summers and shorter winters, or you can be poor.

Sane people: Longer summers and shorter winters sounds pretty good to me.

------
alkonaut
Wouldn't earth based reflection be a lot simpler? E.g artificial
clouds/ice/etc to reflect sunlight off the planet?

~~~
bigbugbag
Like polar ice ?

this would be simpler for sure but it would require very difficult things to
attain such as having people relinquish their air conditioning, stopping
capitalism and consumerism, changing the global industrial process,
diminishing our energy consumption, replacing the current political systems
with democratic ones, returning to ways of producing food that do not cause
soil infertility.

~~~
alkonaut
Exactly like polar ice. The problem as you point out is that polar ice is
_reducing_ which just makes it worse.

And obviously this whole discussion about technological solutions is due to
the fact that all those things you list seem to be impossible or happening too
slowly.

I doubt artificial ice is the easiest solution, but e.g artificial clouds
could be perhaps.

~~~
andai
I saw something on TV a few years ago about a project to make boats which
would spray a fine mist high into the atmosphere, ie. create artificial clouds
to reduce the heating of the earth.

------
xbryanx
The American Geophysical Union is looking for feedback from its members on
geo-engineering efforts like this right now. The draft statement is a good
read: [https://sciencepolicy.agu.org/comment-
geoengineering/](https://sciencepolicy.agu.org/comment-geoengineering/)

------
njarboe
$50/kg to Earth orbit would be fantastic. One could get to a much higher exit
point than the 5.5 km elevation (18,000 feet) they propose for even more
efficient system. Seems like a great mega-project for China. They have the
resources, drive, ambition, tech, and access to many 8 km+ mountains to build
a launch tower on. Hopefully this would spur the US to partner with Chile
and/or Argentina to build one on one of the ~7km peaks in South America.
Denali is probably out of the question, but as military project, maybe it
could be done.

~~~
KGIII
Umm... I'm not sure it is politically feasible to build a rocket launching
facility on Denali. That is gonna make a whole lot of people angry. You should
see what happened when they put wind turbines on the much smaller mountains of
Maine.

Sort of related, I happen to like the looks with said turbines. There are
still untainted vistas.

~~~
NegativeK
Is Denali worth it, given its remoteness, horrid weather patterns, and
distance from the equator?

~~~
KGIII
From the little I know about rocket surgery, probably not. There are better
places to launch from.

~~~
njarboe
From US soil? Not sure the US would put 10's to 100's of billions into a
launcher and not have it in the US. Maybe the Panama Canal land grab route
would be what would happen instead of Denali.

~~~
KGIII
We'd probably use the current facilities. I suppose we could also try for
Hawaii or Puerto Rico. The land grab is also an option, given the likely
political climate if it reaches this point.

My understanding is that closer to the equator is better, with some caveats.

~~~
stevep98
> My understanding is that closer to the equator is better, with some caveats.

For this project, I don't think it matters. They even said they will orient
the launcher vertically.

The reason you normally want to be closer to the equator is that you get some
sideways velocity from the rotating earth, and that is faster nearer the
equator. This is important for low earth orbits because the sideways velocity
is very high.

However, in this case they don't really care much about sideways velocity.
They want to reach escape velocity. As you go higher, the sideways velocity
needed to stay in orbit gets smaller, until finally it's practically zero. So,
any gain they would get from being near the equator wouldn't be needed.

I think.

~~~
KGIII
I'm still pretty skeptical about them putting it on Denali. It just seems
really unlikely - and insanely difficult. It's also considered sacred by some
of the natives, as I understand. I am imagining the outrage.

------
burke
> It seems feasible that it could be developed and deployed in ≈25 years at a
> cost of a few trillion dollars, <0.5% of world gross domestic product (GDP)
> over that time.

Much more optimistic numbers than I had previously guessed.

------
mabbo
It's also been speculated that the same idea could be used to have the
opposite effect on Mars. A cloud of small satellites trying to push _more_
sunlight towards the planet, thereby heating it up.

It's all space-nerd talk for the moment, but none of the technology needed to
achieve these goals is very far from reach today.

~~~
antisthenes
In that case, neither is fusion, which is essentially free energy forever.

It opens up the avenue for many more warming and CO2 mitigation techniques
that are a reality today (e.g. desalination on a global scale and massive
reforestation of Africa and the Amazon)

As well as the ability to stop burning fossil fuels much quicker than
transitioning to solar/wind.

~~~
eloff
It's interesting how you think it's possible to do massive reforestation in
Brazil and Africa. Think about massive reforestation of Europe or the eastern
USA and I think you'll see the fundamental problem with it. That land has
already been put to other use (mostly agricultural use) and cannot simply be
reforested. The government would have to repurchase the land from each
individual land owner to do that which is not at all practical.

~~~
CPUstring
To be fair, France currently has more forests than it did a century ago.

------
gene-h
This project requires millions of square kilometers of high tech satellites.
If we could make millions of square kilometers of high tech satellites then we
could probably make millions of square kilometers of solar panels here on
earth, and not put CO2 into the atmosphere in the first place.

~~~
andai
"The future is already here — it's just not very evenly distributed." William
Gibson

The space based sunglasses would shield the entire earth.

I think it would be more difficult to get millions of square kilometers of
solar panels evenly distributed.

------
drawkbox
Deflecting sunlight in orbit is interesting.

Regarding deflecting light, for a long time white roofs have been pushed as a
reflection mechanism[1] to deflect and lower energy costs thus reducing
emissions. Though white roofs may actually increase warning in the way it
reflects light onto other particles and doesn't help block it from coming into
the atmosphere. Solar roofs capture it better and may be a better emissions
lowering tool.

Seems like a better idea to do it from space, unless of course it goes too far
and is difficult to control.

[1] [https://www.theguardian.com/environment/2011/oct/27/white-
ro...](https://www.theguardian.com/environment/2011/oct/27/white-roofs-global-
warming)

~~~
wellboy
This seems really viable.

Deflecting is still better than absorbing on the roof top, since roof top
means 100% warmth absorption and deflection always less than 100%, probably
only a fraction of that.

~~~
sliken
Your assuming that the atmosphere is more transparent to infrared (from a hot
roof) then optical ranges (from a white roof).

~~~
jwilk
No?

The atmosphere is more transparent to sunlight than to IR, thanks to
greenhouse gases.

That's why absorbent roofs heat the Earth more than reflective roofs.

------
civilian
> 3 trillion dollars

This is why we need a space elevator! Costs would be reduced from $40k / kg to
~$400/kg.

I spoke to an engineer at a space-focused company about space elevators. He,
unfortunately, burst my bubble. While the elevator itself might be feasible,
he thinks that countries would never let an asteroid large enough to act as a
counterweight, with thrusters large enough to move it attached, enter Earth's
orbit. The potential of it being used as a catastrophic weapon is just too
dangerous.

~~~
XR0CSWV3h3kZWg
We'd also need to advance material science and logistics quite a bit. It
sounds like carbon fiber has the tensile strength, but we can't make it in
near the length nor quality we'd need for a space elevator.

The elevator would need to avoid or divert space junk.

And we haven't actually practiced asteroid capture, much less orbit keeping on
a scale that large.

------
xhasid
Would it possible to aim to have these satellites shade only one or both of
the poles? That could solve the problem of reduced sunlight for plants. (Among
other issues.)

~~~
tempestn
ISTM it would be difficult since the sun isn't a point source. Fortunately, as
other comments have mentioned, sunlight is not the limiting factor for plant
growth in most situations.

------
filleokus
Can somebody who understands the subject (or have read the paper more
carefully than me) say how the moment of the shadow on the earth would be?
Would it be fixed on a part of the earth or move, and if it moves, how fast
and in what "orbit". I.e, would some part of the earth get more (much more?)
cloudy days if this would to be implemented?

~~~
ramidarigaz
The inner Lagrange point is always between the sun and the earth (by
definition), so the "shadow" would always be centered on local "noon" and
would pass the each longitude at the same time every day.

~~~
civilian
But the sun isn't a single point, it is big! In the same way that a pencil can
have a sharp shadow but an office building will have a blurry shadow, the
satellites would produce blurry shadows.

I'm not sure of the dimensions of the inner Lagrange point-- I agree that the
shadow would be centered on astronomical noon, but I think it would be so
blurry, and have such a wide blur radius, as to be unnoticeable except as a
change in absolute light.

------
nickt
Sunstorm [1] by Arthur C. Clarke & Stephen Baxter, obliquely touches on this
though with added aliens and a larger threat from the sun.

[1]
[https://www.goodreads.com/book/show/35815.Sunstorm](https://www.goodreads.com/book/show/35815.Sunstorm)

------
davesque
I don't have the technical background to know if this is a pie-in-the-sky kind
of thing, but it seems like an amazing idea. It reminds me of the "Icarus
array" from the book "Echopraxia" by Peter Watts. Of course, this wouldn't
harvest energy but just absorb it.

~~~
sbierwagen
February 2001, "Ice and Mirrors", by Brenda Cooper and Larry Niven. Swarm of
small mirrors used to cool a planet. Mentioned in this Nature article
complaining about the cost:
[https://www.nature.com/news/2006/061030/full/news061030-6.ht...](https://www.nature.com/news/2006/061030/full/news061030-6.html)
Predates Echopraxia by 13 years.

~~~
antisthenes
This is the space version of fusion, "just 20 years away" or "within our
grasp" for the last 60 years.

In fact, it may be even less feasible. Not to sound too much like a skeptic,
but my bet is on terrestrial methods of mitigation, solar/wind/tidal,
reforestation and, hopefully one day, fusion.

Most people underestimate by several orders of magnitude how hard it is to
launch something into space correctly.

------
lifeisstillgood
I remember a quote from a US geo-engineer to the effect of "half of my job is
not to come up with geo-engineering solutions that will be used, but to show
people that plan B is soooo extreme that they start taking plan A much more
seriously"

Citation needed I know but it has stuck with me

------
spenrose
"They would weigh a gram each, be launched in stacks of 800,000, and remain
for a projected lifetime of 50 years within a 100,000-km-long cloud. The
concept builds on existing technologies. It seems feasible that it could be
developed and deployed in ≈25 years at a cost of a few trillion dollars, <0.5%
of world gross domestic product (GDP) over that time."

Oh FFS. If we have a few $trillion to devote to global warming, we can
enormously reduce it using known technologies.

There is an important clue in this spectacular self-own to the emotional
allegiances of the people who get excited about ideas such as this one.

~~~
sliken
How about just invest in a solar powered way to make something useful from CO2
in the atmosphere. Like say a brick. We could make roads and buildings out of
it.

~~~
andai
I think trees stole your idea about 400 million years ago.

~~~
sand500
Yep, look up carbon sequestration.

------
SubiculumCode
Any form of geoengineering that is outside of earth mskes me nervous. Removing
or altering its effect might be precluded if society breaks down (e.g.after a
nucleur war)

------
redthrowaway
So what happens if a big volcano goes off and we suddenly need that sunlight
again? Not too easy to clear debris out of a Lagrange point.

------
anotherbrownguy
I don't understand why people are still obsessed with "global warming". The
political proponents of it have already changed it to "climate change" after
global temperature stopped rising for a decade and it's been almost two
decades now. I would be much worried about "global cooling" i.e. another ice
age.

A couple of degree increase over the next hundred years (which is their worst
case estimate based on the most advanced models, even though no model has been
able to predict anything, only fit historical data) will change nothing. Sea
levels will probably rise by a few feet and people living in their beach
houses will have to find another vacation spot in 20 years after they notice
that the sea has been coming closer to their house since the last decade.

Ice age is just as unpredictable (except they don't even have a make-believe
explanation for it) and could start any time giving us very little time to
prepare. If we want humans to suffer less because of it, the least we should
do is try to give over a billion people who have no access to electricity some
way to make sure that they will be able to heat their houses if it's cold,
like most of the developed world can... in addition, meanwhile, they can enjoy
clean drinking water, washing machines, industries etc.

~~~
tempestn
Most of your assertions here are incorrect. You don't need a particularly
complex model to show that if more energy is absorbed by the earth than is
radiated, which is the case due to greenhouse gasses in the atmosphere, the
temperature will rise until it returns to a steady state at a higher
temperature. This means that even if CO2 emissions stop immediately (which
obviously they won't), the temperature will continue rising for a period of
time (some decades).

A 2 degree rise is considered to be the absolute limit without likely
catastrophic consequences. It is certainly not the worst case.

Sea levels could certainly rise by more than you claim, but sea level rise is
far from the only problem. See here for instance:
[http://nymag.com/daily/intelligencer/2017/07/climate-
change-...](http://nymag.com/daily/intelligencer/2017/07/climate-change-earth-
too-hot-for-humans.html)

If you're being honest about your introduction, that you don't understand why
people are concerned about climate change, then that's a start. If you're
instead trying to convince people of your point of view, please provide
evidence for your assertions.

~~~
anotherbrownguy
>If you're instead trying to convince people of your point of view, please
provide evidence for your assertions.

That is useless. People follow it like a religion, I am merely trying to have
a conversation to few reasonable ones so I can understand their point of view
if they have anything interesting to say apart from repeating the same tired
tropes.

>You don't need a particularly complex model to show that if more energy is
absorbed by the earth than is radiated, which is the case due to greenhouse
gasses in the atmosphere, the temperature will rise until it returns to a
steady state at a higher temperature.

Do you have reference to a graph that shows the amount of CO2 in the air vs
how much heat is absorbed? Has this been isolated? Can't be that difficult to
create a green house and study the relation by varying CO2 concentration.
Could it be that the temperature rise is an independent phenomena which is the
cause for CO2 rise, not the effect of it? None of the political arguments seem
to be questioned ever and no scientific studies seem to come out of it. Given
that most research findings are false
([http://journals.plos.org/plosmedicine/article?id=10.1371/jou...](http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020124)),
there ought to be some research findings that show evidence against climate
hysteria, even if they are wrong, but those don't seem to surface. It is as if
any questioning of political propaganda is systematically silenced
([https://www.youtube.com/watch?v=GujLcfdovE8](https://www.youtube.com/watch?v=GujLcfdovE8)).

~~~
tempestn
If you're asking for references that CO2 absorbs and radiates IR radiation, I
imagine you'd have to look to a textbook or papers from the early 20th
century. That's established fact. As far as evidence that increased CO2 in the
air reduces the radiation of heat from the earth back into space, yes, there
is also plenty of evidence showing that. Here's an article that does a good
job of explaining the science and links to several sources:
[http://www.ucsusa.org/global_warming/science_and_impacts/sci...](http://www.ucsusa.org/global_warming/science_and_impacts/science/CO2-and-
global-warming-faq.html)

This paper from back in 2001 demonstrates that the changes in spectra radiated
from earth as detected by spacecraft match expectations given the effects of
CO2 and other greenhouse gasses in the atmosphere:
[http://www.nature.com/nature/journal/v410/n6826/abs/410355a0...](http://www.nature.com/nature/journal/v410/n6826/abs/410355a0.html?foxtrotcallback=true).
It also links to a number of papers around the supporting science.

Those are just the first two good examples I found. There are plenty more. I
don't agree with your argument (as I understand it) that most research is
wrong, and therefore the fact that there's no research supporting your
position somehow itself supports it. Rather, while of course not all
scientific research is done well, and scientific understanding is always
evolving, that does not mean that it is impossible for anything to be known.
The great deal of evidence supporting human-caused climate change, and the
lack of robust evidence of the contrary, should reasonably lead one to the
conclusion that it is a real phenomenon.

~~~
anotherbrownguy
>If you're asking for references that CO2 absorbs and radiates IR radiation, I
imagine you'd have to look to a textbook or papers from the early 20th
century. That's established fact.

Hmm... the "established facts" for thousands of years in textbooks and
everywhere was that the earth is flat. I guess I should believe in that too.
Anyways, I will link you to an article which argues that CO2 acts as a
coolant:
[http://www.biocab.org/Overlapping_Absorption_Bands.pdf](http://www.biocab.org/Overlapping_Absorption_Bands.pdf)

So, Given that plants grow better at higher CO2 concentrations (as experienced
by indoor growers [https://university.upstartfarmers.com/blog/why-and-how-to-
su...](https://university.upstartfarmers.com/blog/why-and-how-to-supplement-
co2-in-indoor-farms)), it seems like it is good to try increase CO2
concentrations higher and see if we can achieve the desired cooling effect
while we are at it. Meanwhile, we will also be solving world hunger,
preventing deaths due to unclean water, freeing up time used by people of
poorer countries in farming, processing food, washing etc. using industrial
machines and letting them enjoy the same standard of living as the western
countries... all of this can be done by letting them use fossil fuels...
taking the taxes and international restrictions away from the industry.

>
> [http://www.ucsusa.org/global_warming/science_and_impacts/sci...](http://www.ucsusa.org/global_warming/science_and_impacts/sci..).

I read the article and it seems to be posted on a site for "Union of Concerned
Scientists", which it seems is an advocacy group for what they think is
"scientific". I think that is a very closed minded way to view science but
let's examine their claims:

>CO2 has caused most of the warming and its influence is expected to continue

To back this up, they link this IPCC page:
[https://www.ipcc.ch/report/ar5/wg1/](https://www.ipcc.ch/report/ar5/wg1/) and
I finally found the report after some time:
[https://www.ipcc.ch/pdf/assessment-
report/ar5/wg1/WG1AR5_Cha...](https://www.ipcc.ch/pdf/assessment-
report/ar5/wg1/WG1AR5_Chapter08_FINAL.pdf), they could have linked to the
report directly, but OK.

Anyways, in the report, they compare various chemicals and how much heat they
trap. What they don't compare is how much heat 280 ppm of CO2 captures vs how
much 1500 would capture. My guess is not much because a 40% rise in CO2
changed the average temperature by a couple of degrees in the last few hundred
years. So, it seems like the relation is either very weak or that there is no
relation at all. It can't be that hard to create two greenhouses next to each
other, fill them with different levels of CO2 and note the difference and it
is very surprising that nobody has done it... but given how modern science
works, what is much more likely is that the experiment didn't come in their
favor and hence it was never published.

>that most research is wrong

I am not the one claiming that. There have been multiple studies in the fast
few years which have shown that most modern scientific publications don't hold
up on peer review... and most scientists don't spend their time on peer
review. It seems that it is not in their interest to review a study that
someone else published. Making new and extraordinary claims with doctored data
seems to get all the attention from journalists (and hence more funding), so
that is all everyone seems to be interested in doing.

>The great deal of evidence supporting human-caused climate change, and the
lack of robust evidence of the contrary, should reasonably lead one to the
conclusion that it is a real phenomenon.

100% of Nazi scientists believed that Jews were an inferior race. Maybe
scientists are biased by politics of the countries they work in, among other
things? Can you name one other "scientific fact" that has not been politicized
but still "settled"? Let me help you: it doesn't exist. Science doesn't
"settle". It's always open to enquiry and new evidence can always change it.

~~~
nikdaheratik
> 100% of Nazi scientists believed that Jews were an inferior race.

May I direct you to
[https://en.wikipedia.org/wiki/Godwin%27s_law](https://en.wikipedia.org/wiki/Godwin%27s_law)
which suggests that at this point you have likely lost this thread. Don't
worry, you can come back in a few weeks and will likely be able to put up more
FUD about how the climate isn't changing and there's "no way to tell" whether
putting more CO2 in the atmosphere will trap more infrared sunlight.

Nevermind that this property of CO2 is an established fact, and we have Venus
as an example of what a runaway greenhouse effect looks like in real life.
Also ignore the advice of the 95% of scientists who have studied this for
years.

> the "established facts" for thousands of years in textbooks and everywhere
> was that the earth is flat

Most people (including scientists/philosophers) didn't believe that the Earth
was flat. The Greeks used the theory that the Earth was spherical to determine
the circumference of the Earth thousands of years ago
([https://en.wikipedia.org/wiki/Eratosthenes](https://en.wikipedia.org/wiki/Eratosthenes)).
And sailors recognized that the Earth had to be spherical from early
observations with spyglasses as well. The controversy was between religious
leaders who wanted to continue to push the official "Geocentric" model (that
is that the round Earth is the center of the universe) in spite of evidence to
the contrary.

Of course, the fact that the Earth is round didn't affect most people's daily
lives at the time the way climate change will today, which is why they didn't
care much either way. A luxury we do not have.

------
AlexCoventry
If the authors are around, you're missing some backslashes before your dollar
signs, here:
[http://www.pnas.org/content/103/46/17184.full#sec-3](http://www.pnas.org/content/103/46/17184.full#sec-3)

------
hughes
> there is no fundamental reason why launch from Earth by linear acceleration
> to escape velocity of 11.2 km/sec should not be possible

ok... even if you build it 5km in the sky, a 1km long launch rail would still
apply 6,000 Gs of acceleration. Good luck designing a spacecraft that can
survive that.

~~~
sliken
Or don't waste 5km and make the tube 5km. The acceleration drops to 1282G.
Digging a 1km hole drops it to 1000G or so. Not really that much. About the
acceleration a woodpecker head gets, less than a baseball being hit by a bat,
or what a wrist watch can withstand. Under 1/10th that of the electronics in
an artillery shell.

------
barneygumble742
Isn't this what Mr. Burns did on The Simpsons except for Springfield instead
of Earth?

------
whataretensors
Does anyone have links to a good recent research paper on climate change? With
modeling details and dataset. I've looked around but it's difficult to find
the best/most recent knowledge.

------
Nomentatus
"A major technical hurdle to be overcome is the instability of the orbit,
which is at a saddle point."

Tether from the lunar surface, through the Lagrange point.

------
mishkovski
One option is to find a way to decrease human population voluntarily. That
will reverse human related climate change in more natural and comprehensive
way.

------
SCAQTony
How would a "cloud" at the Lagrange point be removed in the event of a global
cool down or "black swan" event occurred?

~~~
cookingrobot
From the article, the L1 Lagrange point isn't stable, it's a saddle.

In the plan described here, the craft would be actively controlled to adjust
how much light they're diverting and at what angle in order to stay balanced
at the Lagrange.

If the steering system is turned off all the reflectors would harmlessly blow
away.

------
amelius
Don't we need the photons to convert CO2 back into O2 through photosynthesis?

------
drc0
simpsons did it
[https://metrouk2.files.wordpress.com/2011/03/article-1300967...](https://metrouk2.files.wordpress.com/2011/03/article-1300967207614-0b51086100000578-330784_636x336.jpg)

------
xitrium
What idiot called this "Feasibility of cooling the Earth with a cloud of small
spacecraft near the inner Lagrange point" instead of "Solar Eclipses As A
Service?"

------
deft
Why not a giant magnifying glass to concentrate the sun and increase temps on
enemy territory?

------
phkahler
This is a shit test.

~~~
andai
It might be!

lifeisstillgood 16 hours ago

I remember a quote from a US geo-engineer to the effect of "half of my job is
not to come up with geo-engineering solutions that will be used, but to show
people that plan B is soooo extreme that they start taking plan A much more
seriously"

Citation needed I know but it has stuck with me

------
kazinator
With regard to stability, just use L4 and L5! Park some anchor objects at L4
and L5, and stretch a big tape-like net between those things, in the middle of
which is the shading device. Problem solved! :)

