Could a giant parasol in outer space help solve the climate crisis? | Hacker News Reader

Could a giant parasol in outer space help solve the climate crisis?

nytimes.com

33 pointsgmays83 comments

That is all well and good, but high CO2 causes other issues than just warming. The only real fix is doing the hard thing, limit CO2.

For example here os one concerning item:

>when we breathe air with high CO2 levels, the CO2 levels in our blood rise, reducing the amount of oxygen that reaches our brains. Studies show that this can increase sleepiness and anxiety, and impair cognitive function

From https://www.news-medical.net/news/20200421/Atmospheric-CO2-l...

- Cognitive effects show up well over 1000 ppm.

- Current atmospheric concentration is around 417 ppm.

- The rate at which atmospheric CO2 concentration increases has been approximately 2-3 ppm per year over the past decade, as observed at monitoring stations like Mauna Loa.

If we hit 600 ppm and don't seem to be slowing down, maybe then I would worry about this but probably worry about ocean acidification before cognitive decline.

I have no expertise in this at all. How do they determine if cognitive effects only show up well above 1000? Is it possible that the testing methodologies aren't capable of detecting changes at a lower level?

Edit(

>In fact, at 1400 ppm, CO2 concentrations may cut our basic decision-making ability by 25 percent, and complex strategic thinking by around 50 percent, the authors found.

If this is a continuous scale, it could be affecting us at lower levels already )

Further, isn't it reasonable to assume that regardless of the above, there will be 'hotspots' of c02 where the concentration may be hundreds of ppm higher than the average/background, at least temporarily (e.g. heavy industry centres, or cities in valleys)?

Edit: The article mentions indoor levels are ~500 ppm higher than outdoor, so if a home is in one of my presumed hotspots, some people might be hitting these levels on occasion.

Oh, people hit that level all the time indoors. One person sleeping in a bedroom with a closed door overnight reaches high CO2 levels. A classroom of students are swimming in it.

I once stayed in a hotel with 1700 PPM in my room. It was a LEED Gold building sealed up tight. We didn't notice any cognitive issues but we made a point of not staying there long.

> - Cognitive effects show up well over 1000 ppm.

"Well over" is as little as 1500ppm. Definitely at 2500ppm. Reaching those numbers in poorly ventilated buildings is easy.

> - Current atmospheric concentration is around 417 ppm.

People mostly work indoors, so atmospheric concentration is not comparable.

> maybe then I would worry about this but probably worry about ocean acidification before cognitive decline.

True, you can always improve individual ventilation in rooms and houses until maybe 700-800ppm in the atmosphere, and at that level I would also worry about other things (ecosystem collapse, major weather events, fires and air pollution).

Indoor air is going to be at some concentration above ambient. Raise the ambient concentration and you raise the indoor concentration. There's already many of indoor concentrations that are problematic.

I think this is an extremely important and little known fact.

We double it every 35 years, so I don't think it's safe to assume linear growth.

at that rate of increase (~300 years to reach 1000+) could we possibly adapt over time? There are probably already humans who are more/less susceptible to high c02 environments.

Individuals don’t adapt, a specie is through selection of best individuals. Since humans mostly managed to escape from selective pressure we are probably not going anywhere in such a short time I guess.

Lowering CO2 is important but is also very intractable international problem full of politics. So it makes sense that various people concerned about the environment propose to make an end run around all this mass of irrational savage humanity

Yeah and virtually every source of pollution brings more to the table than co2... much nastier things usually

I mean, that's true, but not relevant at the scale of the CO2 in the atmosphere. Think about breathing from a paper bag - your exhaled breath contains about 4% CO2, and after several cycles of re-breathing the same air, that percentage will increase, and you'll start to notice the effects you described, in the range of parts per hundred.

CO2 from the ambient air you breathe is currently 0.04%, in the range of parts per ten thousand, two orders of magnitude lower than where you feel the effects you described.

I mean yeah, lets destroy our civilization (or whole mankind, who knows what desperate collapsing nations with nuclear weapons will do) as we know it so that we won't risk breathing 0.3% higher co2 concentration, seems logical. We would be such losers to use some simple cheap trick to give us some time to figure things out.

Yes...but.

I ran the numbers on this idea many years ago and it's doable with current technology.

The good news is that the day it's deployed global warming stops instantly. It will still take a while for the planet to cool down, and much longer still for the ice caps and glaciers to return, but the warming up stops immediately.

The bad news is that it would probably take decades to deploy, and it will cost $Trillions, just as tfa points out.

The even worse news is that it does not stop the acidification of the ocean and it might even give fossil fuel burners an excuse to continue business as usual.

It might be a good idea after we stop dumping carbon into the atmosphere, but not before.

Space-based geoengineering is technically superior to stratospheric aerosol injection, but the latter is practical almost immediately, and is likely to be much cheaper no matter what. In my view that outweighs concerns about the ozone layer.

It has also been pointed out that launching enough space-shades with chemical rockets would itself deposit a considerable amount of particulate matter in the upper atmosphere, so to be really atmospherically 'clean', one would need to complement geoengineering with a radical new launch technology.

How can it works? The moon is already huge and when it’s eclipsing the sun it’s only shading a small spot.

One would need to block a significant fraction of the solid angle between the sun and earth. The smallest side is on earth side, and that would require an object the size of the planet.

Looks like we’re hanging on anything to procrastinate the mandatory society shift.

The shade would be much closer to the Earth than the Moon. The article says shade would block 2% of Sun light. It would "would have to be about a million square miles, roughly the size of Argentina".

2% is about the ratio of earth cross section area to Argentina surface, that sums up.

Proximity should not impact the efficiency as the Sun is not a point source and what is important is effectively the ratio of lit/shaded surface.

Now that’s 2.8 millions of square km that is 2.8e12 square meters. Mylar at 7g per square meter would mean sending up 19.6e6 tons for the sail only.

Low orbit future best payload seems to be 250 tons, the sail would then take about 8000 rocket launches if I’m correct.

And then the sail’s structure, moving it to high orbit, the steering system to manage the tremendous solar pressure, etc…

It avoids actually solving the very lucrative pollution problem, so this is a prime candidate.

I'm convinced we'll do literally any and everything besides stopping the root cause.

Well that's easy to imagine because the root cause is so deeply rooted and complex, and stopping it would be literally a Herculean effort across billions of people in hundred+ countries, many of which would have to work against their own primal surface-level interests (e.g. good luck convincing poorer or even affluent countries reliant on oil exports that they should decarbonise and coordinate efforts with other countries to decarbonise, even if you directly give them the money to allow them to decarbonise which nobody is going to do).

This narrative bothers me because it removes the personal responsibility from people who are… responsible. Like, we can’t tell people they can’t do anything to fix it and so they shouldn’t feel bad for continuing life as normal… and then be surprised when they don’t change their behavior.

Guess what, you should feel bad. History and your descendants will judge the hell out of you. Billions will die and your small part, while certainly not the cause, will still be pinned to you for your acquiescence to it being “too hard” to change.

Now, if everyone in the developed world got this message suddenly change isn’t so hard.

Im skeptical about this solar shield thing but how big of a problem is CO2 on its own? (without climatic effects)

Ocean acidification & acid rain

Acid rain is not caused by co2 for sure. How big a deal is ocean ph falling? Wasnt it lower than now a few million years ago?

While it's true that acid rain is not caused by CO2 per se, it is generally caused by products of combustion. The context was specifically the other harmful effects of the root cause - burning fossil fuels - which a solar shield would not address. So it's wrong to narrowly focus on CO2.

As for ocean acidification, it's a pretty big deal: https://en.wikipedia.org/wiki/Ocean_acidification#Predicted_...

"Importantly, the rate of change in ocean acidification is much higher than in the geological past. This faster change prevents organisms from gradually adapting, and prevents climate cycle feedbacks from kicking in to mitigate ocean acidification. Ocean acidification is now on a path to reach lower pH levels than at any other point in the last 300 million years.[81][71] The rate of ocean acidification (i.e. the rate of change in pH value) is also estimated to be unprecedented over that same time scale.[82][14] These expected changes are considered unprecedented in the geological record.[83][84][85] In combination with other ocean biogeochemical changes, this drop in pH value could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean, beginning as early as 2100.[86]"

Fascinating thank you

The good thing is that it's easily and nearly instantaneously reversible.

From an engineering standpoint, it it blocks 2% of solar radiation as stated by the article (and let's suppose we can send that amount of stuff in space) it will have to reflect that amount of solar radiation, not absorb a significant amount of it (because of heating and dissipation) and direct anything it absorbs away from Earth as much as possible.

From my understanding, instantaneous reversability property is problematic because we haven't actually solved the underlying problem.

Now we've just got a "sail maintenance" problem: we put the sail up, continue to burn ff now unimpeded by the worst side effects. 1-2 decades later, if the sail were to fail / lose funding / get neglected by temporary geopolitical conflict, earth rapidly accumulates all of carbon debt we accrued.

Even if it absorbs and re-emits everything, that would probably be fine. Black body radiation is emitted in practically every direction, and only a miniscule portion of that would hit the Earth.

The bigger problem with absorption is potentially heating the material to the point of vaporization.

All that said, the most practical form of this would probably be something like a fresnel lense that uses refraction or a structure that uses diffraction to redirect the light rather than reflect or absorb it.

How about the material that the Webb telescope sunshade uses?

For people who want to explore this potential future I recommend Neal Stephenson's Termination Shock as a near future sci fi read.

Not saying it will happen like that but he brings up some interesting potential cause and effect

If we mitigated just the warming issue through geo engineering, how severe are carbon emissions impacts on our environment?

Would we be able to go back to emissions increasing, or is this causing loss of other biodiversity?

CO2 dissolves in water to become carbonic acid which causes ocean acidification. In the ocean this causes problems with most (all?) crustaceans, molluscs, and corrals by interfering with their ability to build calcium carbonate structures by preferentially binding with carbonate ions. Since many of them are keystone species, this will eventually lead to catastrophic effects as other species that depend on them either collapse or those they prey on grow out of control. The more atmospheric CO2 goes up, the more of it dissolves in the ocean and acidifies it.

Sooner or later that acidity begins to interfere with phytoplankton and other photosynthetic organisms in the oceans, which account for two thirds of oxygen production on the planet. It just kinda gets worse from there.

https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_at...

Whatever we do - it better be easily reversible or decay relatively quickly. It would suck to launch a solution that overshoot or causes some unforeseen problem and we can't quickly revert it.

Serious question. Do ppl really think we can do anything about it? (Environmental issues we are facing - climate warming is just one of it)

This is mostly a political problem. We all know that without world goverment its impossible to tackle problems like that. And currently we see moves destabilising geopolitics and not uniting them.

Im seriously see only gray scenarios moving forward till mby we magically find infinite clean easy to produce and portable source of energy that producers will be willing to share for free.

You as an individual can stop driving and instantly cut your co2 emissions by half or more.

But that’s not what you’re asking is it? Ok, you can show up to city hall and advocate for making your city a place where you don’t need a car. But that’s probably also not what you’re asking. How can you be a hero and save humanity? You can’t. You can reduce your moral responsibility for what’s happening though by reducing your part in it.

Transport is just one source of CO2, and can be mostly solved with electric vehiclezs. People buying stuff they really don't need is a much bigger problem.

Transport is one of the easiest to substitute with alternative means in many parts of the world. Then you don't have the CO2 from manufacturing the car (electric or not) and you don't produce any while traveling. My family and I decided to get rid of the car 3 years ago and we didn't look back. We are fortunate enough to live in an area with acceptable public transport and we got ourselves bikes as a supplement. We ended up renting a car 2 times in 3 years, one of which was a moving van. Won't work for people living in remote areas, but it's doable for many.

We have also not used a plane in the last 4 years, but that's something many won't be willing or able to do.

It's at least worth thinking about if nothing else.

What material would this have to be made of to not melt?

Edit: I'm not that familiar with radiation and its parameters/properties. My assumption was that it would accumulate heat. I'll go look up if radiation is a function of heat, then I suppose it could become stable at some temperature. It's surprising to me that you can block out some of the sun from a good area on the earth and not have melting bits.

It's not as hot as you'd think. Solar panels (highly absorbing) reach slightly over the boiling point of water in direct sunlight. Metals work fine, so do a surprising number of composites and plastics.

* Aluminum, Magnesium, Titanium, Berylium

* Graphite/epoxy, Aramid/epoxy, Glass/epoxy

https://www.sciencedirect.com/topics/earth-and-planetary-sci...

> What material would this have to be made of to not melt?

I would just use a giant array of solar PV panels as screen, then build a huge coil gun nearby and use all that energy to deflect potential dangerous asteroids by throwing them projectiles made of collected and recycled debris from decommissioned satellites.

Something with a black back to radiate the heat back out to space.

This is (very) stupid.

Mushroom. What other material would a parasol be?

Reflective mylar.

i hear it's extremely cold out there

It is both incredibly hot due to solar radiation, and extremely cold, due to the lack of atmosphere to transfer heat.

The sun-side of this parasol will be all melty, while the shade side will be extraordinarily chilly. Whatever it is made of, will need to withstand that extreme thermal gradient.

> It is both incredibly hot due to solar radiation, and extremely cold, due to the lack of atmosphere to transfer heat.

If the temperature of the moon is anything to go by, it's hot but not too hot. According to NASA:

>Temperatures near the Moon's equator can spike to 250°F (121°C) in daylight, then plummet after nightfall to -208°F (-133°C).

https://science.nasa.gov/moon/weather-on-the-moon/

Something like aluminum foil should work fine.

There's also the possibility of occasional space debris or solar flares striking the parasol

Very minor possibility though as any space debris that is not already in a semi-stable orbit would most likely have been filtered out by the planets before making it to any location inside of Earths Orbit, and a space parasol would be fairly small on an astronomical scale.

"To block the necessary amount of solar radiation, the shade would have to be about a million square miles, roughly the size of Argentina, Dr. Rozen said."

"Dr. Rozen said his team was ready to design a prototype shade of 100 square feet and is seeking between $10 million and $20 million to fund the demonstration."

In a better world, if every country agreed not to destroy each other for a decade and applied their defense budgets, it's doable. Global defense budget is approximately 2.2 trillion as of 2022, according to Statista. Granted, that would cause of a lot of unemployment.

Whereas sulfate dispersal in the stratosphere would cost about 700 million per year. Over three orders of magnitude less money.

Unclear whether a crash decarbonization program would be more or less expensive than that, though.

The hubris of people who acknowledge our lack of foresight that resulted in the accidental geoengineering of climate proposing such a dangerous project that could kill everything without understanding the implications. This is a harebrained scheme of ridiculous proportions.

I thought we already solved this problem [ONCE AND FOR ALL!](https://youtu.be/0SYpUSjSgFg?si=9Oodfb1SgHvTZWLa)

It would be "astronomically expensive", they said. :0

Actually.. No, if it's on a inner orbit, synchronous to the earth, it's just a dust flake throwing a shadow on a peeble. Could even shape it and foils or flakes need little structure. And as they are lights ails, if you throw them lightly inwards, they would automatically disperse. Still problematic approaxh to behavioral change, but if the species is not capable of that, for now, cause to feral, one could make due.

Ps: this would reduce solar efficiency..

it just needs to have a spider like robot that can patch the holes

the US has been investigating these ideas since early in the cold war. It started as a means of mass destruction (could we silently reduce solar radiation over russia and cause their crops to fail?), but really could be a means to cool down the ocean.

There are tons of other impacts of carbon, but we could reduce the solar energy hitting the ocean with currently technology if we needed to.

Most probably, no

There are hypothesis that global warming is intrinsecally related to planetary dynamics, such as a giant volcano exploding under the ocean, and similar events.

But what would happen if you said aloud that nothing can prevent further global warming, and it is actually expected to increase to levels that will make soon some great areas in the planet uninhabitable.

Probably the best - for some - is to keep the CO2 discourse at high pitch.

How would the orbital mechanics work? Wouldn’t the shield orbit faster around the sun than earth and constantly need adjusting?

https://science.nasa.gov/resource/what-is-a-lagrange-point/

similar thing that keeps the james webb telescope in its current position

Wouldn't it be easier to put a lot of smaller objects between the Earth and Sun to reflect light rather than one big one?

It's too large to be a single object anyway. It has to be a swarm.

Looking at it over the long term, it's something we will need to do regardless of co2 emissions as the sun heats up over it's lifespan. The more interesting part of it is that I've you do Earth you have the tech and infrastructure to do the same to Venus and do the opposite to Mars. Combine the solar shade with some solar panels and you are well on your way to becoming a Khardeshev II civilization.

It's a shade the size of Argentina.

Argentina is a very big country

The Kardashev scale is a scale whose smallest unit is our current civilization, the scale easily accommodates Argentina.

Yeah but that scale is fantasy/sci-fi. Baked within it is a kind of assumption that it is a scale we should be moving up through, which is not a given.

So I guess it is reasonable if you think the destiny of life on earth is to “conquer” the “full power” of the sun.

Kardashev scale is a fantasy - a dangerous one because very intelligent people spend their talent and societies' resources pursuing it.

Indeed. Argentina is only 3.5 times smaller than the USA. It's a lot of stuff to send to space.

This is an odd one though, as Argentina's shape is very long an narrow. I doubt that shape is what is needed. So just looking up something with the similar sizes based on area doesn't really help when the shapes are so different.

Feature Request: I want to measure current CO2 levels around me with my smartphone.

This tech could make other planets habitable too.

I recall a certain prominent fictional billionaire from The Simpsons creating a parasol to block out the sun (with murderous results...): https://www.youtube.com/watch?v=IyjJbhuwGkU

(And tinfoil hat time-- how does this not get used as a geopolitical football?)

This feels an awful lot like the plot of another Bond movie. It would be a shame if something happened to your nice crops over there...

could it yes, but that would be predicated on some one with a space agency funding it. NASA, good luck convincing congress to fund it enough to maintain what they have, let alone solve a problem half of congress deny exist for ideological reasons. European space agency smaller than NASA. Russia to busy spending all of their money trying to take over their neighbors, china maybe not holding my breath for the country building more coal plants and that has daily air reports for their capital to do anything about climate change, India to poor. I mean there is space x but Musks seems to be too busy frying his brain on drugs with his board to actually do anything other than turn twitter/X into 4chan while lighting his equity on fire.

gotta stop manbearpig

There is no solution to the climate crisis. Everything that uses a solving perspective is deeply flawed. The decisions we make today will decide how many billions will die and how uninhabitable the world will become for our grandchildren and many other species. The train for if has long departed, all we have left is a question of how bad it will be.

"The problem" is modernity, focusing on CO2 in isolation is naive.

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