Blocking Out The Sun: Viable Climate Countermeasure Or Absolute Madness?

If there’s one thing humans hate, it’s exercising willpower. Whether its abstaining from unhealthy foods, going to bed early, or using less energy and reducing greenhouse gas emissions, we’re famously bad at it. Conversely, if there’s one thing humans love, it’s a workaround. Something that lets us live our lives as the carefree hedonists we are, and deals with the sticky consequences so we don’t have to.

One such workaround for the issue of climate change is a doozy, though — blocking out the sun’s rays in order to cool our warming planet.

How Would It Work?

Stratospheric aerosol injection aims to reduce global temperatures by reflecting sunlight back out into space before it warms the Earth. Other geoengineering techniques aim to help cool the Earth, too. Marine cloud brightening aims to also reflect more sunlight, but from a lower level of the atmosphere, while cloud thinning aims to reduce the heat trapped on Earth by Cirrus clouds.

The basic theory is simple. By injecting aerosols — tiny little particles suspended in gas — into the stratosphere, we could reflect more sunlight back out into space, rather than letting it warm the Earth. The idea is to reduce the amount of heat coming in from the sun to make up for the extra heat trapped by higher greenhouse gas levels in the atmosphere. The concept is well understood, and has been demonstrated in the past. Events such as major volcano eruptions have lofted huge amounts of particulate matter into the atmosphere, with a measurable cooling effect as the result.

Of course, if you’re getting visions of James Bond villains or the infamous Mr. Burns, it’s important to note that the aim isn’t to blot out the sun entirely. Perpetual night would have overall negative consequences, leading to total crop failures and a resurgence of goth subcultures. Instead, the idea is to add small amounts of particulates or aerosols into the atmosphere to increase the amount of sunlight reflected by a few percent on average. The amount could be varied to maintain global temperatures in a desired range.

Why Aren’t We Doing It Already?

While the basic theory is straightforward, the devil is in the details. The climate system is a complex one, with  many moving parts that all interact with each other. A small change in one area can have unexpected or undesired effects in another. Opponents to the technology fear that such changes to the chemistry or temperature of the stratosphere could have drastic effects on rain patterns, for example. This could lead to wild shifts in weather, or lead to droughts in crucial farming areas leading to major food shortages.

There’s also engineering issues to contend with. It’s one thing to create reflective aerosols in a small atmospheric region for testing; it’s another thing entirely to do so at a scale that will have real-world effects on global temperatures. Getting this right involves careful consideration of the emissions cost of procuring materials and flying them up to deliver them to the upper atmosphere. Logistical issues are a very real concern, too. It may prove that it’s simply impractical to create enough aerosols in the stratosphere to cool the earth without simultaneously spending huge amounts of energy to get them there.

Stratospheric Experimentation

The balloon platform makes for a simple and cost-effective science platform. The SCoPEx team believes that a full-scale stratospheric cooling project would likely use conventional fixed-wing aircraft, however.

To investigate these issues and learn more about the process, the Stratospheric Controlled Perturbation Experiment (SCoPEx), based at Harvard, is investigating the technology. The experiment plans to loft a balloon into the upper atmosphere, and disseminate particulates over a limited area to study the effects. Experiments will involve tests with sub-micron calcium carbonate particles, chosen for their near-ideal optical properties and expected ozone-safe attributes. Later studies may explore other materials, such as sulfates, already present in the stratosphere, though considered less optimal due to their role in ozone depletion and the amount of heat they can absorb from the sun.

However, the project has faced major setbacks in recent months. After partnering with the Swedish Space Corporation to build a test vehicle, the mooted June launch for a shakedown of the vehicle’s systems was cancelled. Local environmental groups and others oppose the project, on the basis that it could damage the Earth’s climate, and that geoengineering on such a scale should be avoided at all costs.

The SCoPEx test balloon was due to launch in June to shake down the vehicle’s control systems. Public opposition has stalled the project for the time being.

While the initial launch was solely to test out the balloon platform and would not deliver any test material to the atmosphere, the mission was nonetheless cancelled in the face of public dissent. The SCoPEx project has elected to undergo further public consultation in the meantime, in the hope to assuage fears, pushing back any potential launch until 2022 at the earliest.

The incident hints at the controversy around the very topic of geoengineering. Broadly, opinions fall into two camps. There are those that believe we should focus solely on reducing emissions, and that any alternative technologies are a distraction that don’t help solve the root issues at play. Others believe that the world’s slow progress at reducing emissions means that other solutions are desperately required in order to avoid the worst outcomes possible from climate change. Regardless of opinions in the broader public, research into the technology is beginning to pick up steam; the US government recently funded the National Oceanic and Atmospheric Association (NOAA) with $4 million to research the concept. 

It’s likely that the debate will rage on for some time, but with money continuing to flow into the field, it’s likely we haven’t heard the last of these plans to dim the light from the Sun. It may turn out to be impractical, or even wildly disruptive to our global climate. But, until we do the science, we’re never going to know. When we do, expect to read about it here!

155 thoughts on “Blocking Out The Sun: Viable Climate Countermeasure Or Absolute Madness?

      1. Though, the premise in snowpiercer is that the efforts to reverse climate change were done too quickly and too far. Though to a comical degree, not to mention the other oddities of the show….

        But any efforts to manipulate the climate at large tends to have unforeseen consequences.

        In my own opinion, it would likely be better to paint all the roofs white to reflect away more of the sun’s rays that way instead. Not to mention design buildings to naturally avoid letting excessive heat build within, instead of just “solving” the design problems with air conditioning.

        One could also argue that roads should probably be made in a color that isn’t black. As to reflect away more of the light that hits the surface.

        Putting stuff into the atmosphere to block out some of the sun is just another example of how stubborn humanity is to change. And such efforts would likely impact the amount of light exposure that vegetation gets to see. And when plants sees less light, they actually need to breath more. (Yes, plants do produce carbon dioxide at night and this is why you shouldn’t sleep in a greenhouse.)

        In the end, reducing the amount of incoming light is honestly the wrong solution to our current problems.

        Currently the world is covered in more highly light absorbing surfaces than it has likely ever been, and this is part of the problem. Greenhouse gases is another part of the problem. And then there is the long list of other issues.

        1. “In my own opinion, it would likely be better to paint all the roofs white to reflect away more of the sun’s rays that way instead.”

          Uh, yeah, no. That’s just moving heat around.

          1. Increasing the albedo of the ground does work, because the IR coming from the sun that reaches the ground is at a shorter wavelength that goes right back through the atmosphere. If it is reflected rather than absorbed, the heat doesn’t stay.

          2. This whole idea is just moving heat around, throwing more of the suns energy back into space before it hits the atmosphere is going to be more efficient for the same % reflection over the same area than throwing it through the big blanket of atmosphere, but the ground based systems are simple, really really really cheap (like basically free), easy to do, really will work and have other gains like reducing AC energy requirements.

            If we have gotten to the stage we absolutely must divert energy from our atmosphere as we can’t do enough from the ground this idea might become viable enough, and could perhaps double as a cloud seeding platform to help correct the wonky climates drought conditions… But while there are so many simple effective little changes to do from the ground its a daft idea, way to expensive, far to fiddly, unpredictable, and you have to keep doing it rather more often.

            A bit of white paint, and improving energy consumption and generation methods does have continuing work, but nothing like the level of lifting such vast quantities of dust up again and again, as its not like it will stay there…

          3. Air conditioning generates heat while moving heat around, creating a net gain in heat.

            HaD recently featured an article on a new paint that can reflect so well that surfaces actually cool in direct sunlight. https://hackaday.com/tag/white-paint/

            The ‘snowball effect’ related: reflect enough sunlight and a self-reinforcing ice age could occur.

          4. I’m from Almería; the biggest greenhouse surface in the planet aka “the sea of plastic”. There are many studies confirming that indeed the temperatura has decreased in this particular city in the last 20 years while surrounding cities has increased

      2. More like The Matrix…

        >Morpheus: We don’t know who struck first, us or them. But we do know it was us that scorched the sky. At the time, they were dependent on solar power. It was believed they would be unable to survive without an energy source as abundant as the sun.

        If you block the sun, then you mess up a whole bunch of things including those renewable energy sources and food. Solar power is the first one to go. Reduce in evaporation from oceans/lakes, so little rain fall, crops/food growth problems, no salt making from sea water. Without little rain fall, no river, no hydro power. Reduced power into the weather system, reduced power generation from wind.

          1. You’re completely missing the point that he’s talking about the movie “The Matrix”, in which *all* of the solar output was blocked for decades on-end, essentially creating the worst possible kind of nuclear winter.

            Nobody is suggesting that, that’s not what any of this is about, this isn’t a post about humanity’s collective suicide, and it’s so incredibly disturbing that you seem to believe it is.

            If we PARTIALLY block out the sun to mitigate the effects of global warming by reducing the amount of energy from the sun that gets to the ground, it would be a very low reduction, and it would have a very minimal impact (if any) on agriculture… No Monsanto/green-houses conspiracy going on here…

      1. What typically kicks off those changes? Could it be large releases of CO2 and methane into the atmosphere, as the geological record shows?
        Because if so that–when combined with the fact they we haven’t detected a significant increase from natural sources–means that the source of the change in atmospheric composition only has one logical explanation: the apes that are dumping millions of previously sequestered gases into the air.

      2. but this is not natural, we created environment where year after year there is surplus of CO2 added into atmo.

        It will lead to runaway effect turning earth into Venus. or we ‘fix’ the atmosphere with a patchwork last ditch attempt and hope we have accurate enough solution for immensely complicated system of dependencies that is our planet so we don’t fuck up something – aka snowpiercer.

        1. “It will lead to runaway effect turning earth into Venus”

          Will it? All that carbon heading to the atmosphere was life at some point, and before than it was air at some point.

          Sure climate change will cause crop failures and the deaths of billions, but it won’t end life on earth.

          1. Oh, thank god. That’s so reassuring! Well, let’s keep at it boys! Life on earth won’t end! Intelligent life, maybe, but I’m sure some microbes will stick around and remember us!

          1. Care to explain Venus’s scorching temperatures above those of mercury which is closer to the sun? All those clouds must surely reflect and block a bunch of the sun’s rays. I’ll wait.

          2. Its closer to the sun, the atmosphere is more or less PURE CO2 its 90 times denser than earths atmosphere. The pressure on the surface of Venus is about the same as under 1km of ocean. It is so far som being comparable to anything on earth that anyone making these ridiculous doomsday claims deserves to be slapped in the face.

        2. That’s impossible because Venus has a hell of a lot more atmosphere than Earth. Its surface pressure is the same as 900 meters below sea level on Earth. The massively thicker atmosphere holds much more heat and would do so no matter what its composition.

          About 2613.9 watts per square meter of solar energy strikes the top of Venus’ atmosphere VS 1,360 for Earth, so orbiting closer to the Sun also contributes to its higher temperature.

          A Venutian day and night lasts 2,850 hours, that’s 118 Earth Days, 18 hours. That allows the solar heat to really soak into the surface deeply, so that despite the long nights of 1,425 hours little of that baked in heat can leave through the thick atmosphere.

      3. The peak of one ice age to the next is a 100K cycle. There is a 10K interglacial period where the ice melts almost completely before reforming and lasting for 90K years.
        We should be on a swing back to an ice age but we’re not on track for that. As our orbital wobble brings parameters together to bring us back into long lasting glacial periods. But atmospheric chemistry trumps orbital variation.

      1. For once they have the power to “dispose” of everyone that doesn’t share their ideas, do you thing for a New York Second that they will ever reach the point of “enough”? Or will they just keep finding new reasons to “dispose” of others? What has history shown in that regard?

        1. After few hundred thousands it becomes a slippery slope…

          There is a solution, however. Let’s just limit the access to media, good jobs and services for people who believe this “manure”. Or charge them extra for their stupidity. For example an anti-vaxxer got Covid? Force him/her to pay for treatment. Or refuse treatment as “Covid doesn’t exist”.

          Recently polish episcopate announced that some Covid vaccines are made with cells from aborted fetuses (babies in their nomenclature) and thus any catholic should avoid them. Okay, but these catholics should avoid most of medicines, including over-the-counter drugs, as all of them were tested using cell lines developed from fetuses aborted some 50+ years ago. Let them die for their beliefs, as their god apparently likes that…

    1. *Dude*.

      It’s « always presented with leftist talking points » because the right is ignoring the issue and promoting conspiracy theories and complete denial of the science on the subject, leaving *ONLY THE LEFTISTS* to respect the science and facts on this subject.

      In that concept, do not be surprised if the solutions proposed smell like the left. If the right did not lie on this issue and bathe in denial, they would be proposing solutions too, and there would be balance here.

      But you can’t propose solutions to a problem you pretend does not exist.

      That’s the issue here.

      1. I’m conservative, and I do believe that we “may” have affected global climate through rampant [ab]use of fossil fuels.
        But, I do not see any workable solutions to the problem.
        Most, if not all, of the “solutions” proffered seem to be addressing the problem of
        “How can we limit individual freedoms while enriching and further empowering ourselves?”

        1. « I’m conservative, and I do believe that we “may” have affected global climate through rampant [ab]use of fossil fuels.
          But, I do not see any workable solutions to the problem. »

          The same way an anti-vaxxer does not see any evidence that vaccines are safe, and a flat-earther does not see why we think the Earth is a globe.

          If you do not look, you will not see.

          All those who have actually seriously looked into this know about those workable solutions, this is well established science.

          Let me ask you: Do you not know of any solution, or do you know of solutions, but do not think they are workable?

        2. The issue lies on both sides of the political spectrum.

          For reference – I’m also conservative, and believe humans are having an impact on climate change (its more common than you think – we can read graphs). However, is it an imminently world ending problem – no. We have much larger concerns to tackle such as raising QOL within developing countries (HINT – this will help climate WAYYY more than any nonsense left generated green deal or climate accord no-one actually adheres to.)

          You see the right reject climate science because they’ve been told over and over that the world will end in fiery doom unless taxes are increased. The logic doesn’t make sense, so it’s rejected.

          See the “population bomb” as a perfect example of this same false logic. Mid century everyone claimed overpopulation would end the world. Well – it didn’t and modern “global warming” scare tactics replaced it as the popular political tool.

          Now – there ARE solutions. If you really want to reduce environmental impact, the answer is to massively develop Nuclear Power (fission is fine; we shouldn’t wait for fusion). With unlimited clean power, we can mass produce crops in huge warehouses with mostly closed loop systems – eliminating strain on crop producing land while still feeding the world. With unlimited power we can sequester CO2 from atmosphere and store it, etc… We can allow developing countries to actually move past burning fossil fuels instead of giving them false hope with extremely expensive and unreliable wind and solar. The list goes on…

          Banning plastic straws ain’t fixing shit.

    1. Why don’t we put a giant rocket booster on the moon, and park it a few percent into an eclipse, so it blots out enough sun to cool the earth?

      Asking for my friend Elon…

      1. You’d need to haul the moon to about 40 times it’s current distance from the earth so it sits in the Earth-Sun L1 point, or else it’ll just fall on us and cause a faster kind of climate change.

    1. Who gives you the right to add CO2 to the atmosphere from your car, electricity usage, air travel, or other consumption? It might be nice to have a single governing body making these decisions, but many people are already affecting the environment with no permission. Why shouldn’t these people be allowed to make some positive changes? Their method is new and untested but the fact that they are making changes is not new.

      1. Pollution is a part of life, ever since man learned to make fire. That’s not to justify it, but it was always there – the per capita has simply grown over time. And since everyone is ‘guilty’, no one can can deny another the ‘right’ to at least *some* CO2 pollution.
        Still, one person’s pollution has negligible influence on the climate – there are just so many of us. By contrast, this plan is thought up and executed by a relatively small number of people, yet should have a significant impact on the climate. So it will affect everyone – globally – who may not all agree.

        I’m not debating against, just saying the question is valid. Will they seek global (governmental) approval?

          1. If I knowingly accept cash from you that I know you got with a murderous rampage in a bank, do I not share a little of the guilt?

            Corporations may directly cause the majority of pollution, but they do it at our behest. We buy their products, use their services, collect from their payrolls. Most of us do anyway. I do. We can’t just ignore it and say its their fault while buying HILARIOUS Nicholas Cage throw pillows from Wish acting like it doesn’t have an impact.

      2. “ It might be nice to have a single governing body making these decisions,”

        Seriously?! Most of the world’s problems are due to governmental incompetence, and you think a global government would do a better job? The lobbyists would have lobbyists. You’d need a form to submit a form.

      3. “Who gives you the right to add CO2 to the atmosphere”

        LOL , should we stop breathing too?
        Lack of education and over-population appear to be the only issues, at present.

      4. I live on land with enough greenery to cover my emissions many times over. I’m tired of being lectured by professional liars with 4 houses and thrice weekly plane trips.

    2. Money.

      Rich people with it who likely stole (selling expensive crap we dont need) it from the rest of us, and governments who stole (tax) it from the rest of us.
      Who contributes most to the problem in the first place?
      Rich people with money.

      So you can have your cake and eat it.
      If you have the money.

      Maybe we should fix the money problem which itself is a giant ponzi scheme everyone pretends isn’t, and once we stop deluding ourselves that forever growth is a thing, we might believe in climate change.
      If you can find a way to produce exponential profit from a method which combats global warming, you will fix climate change overnight.
      Like striking oil, but without the bad bits.

      But because we can’t/wont see the end game until it happens, we will walk right into it as no one is going to blink first “at their own expense”.
      It’s a giant game of chicken, except the loser gets to say I told you so, but we all die anyway.

  1. So, lets get rid of the symptoms of a warming climate but not really do something about the cause. That is what it would result in. Oh, see, it not getting hotter and is cooling; we can continue as we have been doing and need not change. A deeply flawed technological thinking style. We need less technology to solve our problem, not more.

      1. Wouldn’t enough animals to eat enough grass then fart way too much CH4 (which is 50x worse for the climate than CO2 is) ? Sounds like there might be a possible flaw in this. Should at least do the math, but just a far-off look at the concepts is a bit worrying.

      1. That would depend on how exactly the solar radiation is reduced. If there’s a similar amount of red and blue light reaching the ground, but less green and infra-red, the plants can fix as much CO2 as they do currently.
        Not saying there wouldn’t be other unintended consequences, but on the face of it the one you’ve mentioned can be side-stepped.

        1. The issue is though the following.

          If we put something into the atmosphere that reflects the incoming IR into space, then it will also reflect the IR emitted by the ground back to the ground as well. (if you can solve that, then the Nobel committee has a physics price to give you for breaking the laws of thermodynamics.)

          The reason this is a problem is due to the fact that the vast majority of the thermal energy emitted by the ground is in the IR part of the spectrum. Ie, the “solution” to reflect IR is what we refer to as greenhouse gases, and that isn’t a solution to our problem.

          1. The ground radiates in a different part of the spectrum than the sun because of the different temperatures (black body spectrum). This allows you to tune the particle size such that it’s transparent to long wave IR but reflective to short wave IR from the sun.

      2. And then there is the fact that plants also do breath and produce CO2 themselves when it is too dark to keep photosynthesis going.

        I don’t think reducing the amount of incoming light is the solution to our problem.

        The problem is rather that the world is covered in more highly absorbing surfaces than it has ever been before.
        Considering how the sun gives us about 1000 W/m^2, while a 30C perfect black body gives off only about 40 w/m^2. A fairly drastically difference. (ie, 1 hour of mid day sun will take over 25 hours to radiate back out into space. Obviously our day/night cycle isn’t that unevenly skewed world wide.)

        Making our asphalt roads more gray would likely reduce the amount of absorbed energy fairly drastically.
        Not to mention painting roofs white, among other minor changes.

          1. I have actually been thinking of how effective such a solution would be in practice.
            All one would need is panels that rotate at one revolution per day. A slow steady speed, likely driven by a small motor a few batteries and some solar panels.

            How much of a local cold island it would create is a good question.

            But the greenhouses in Almeria is currently having that effect on its local environment, but that is a fairly huge area…

          2. > Fill the deserts with panels that are painted white on one side, black on the other, and flip them around at sunrise. Reflect during the day, radiate during the night.

            If you are going to put in the work of having actual physical panels solid enough to flip/rotate around, it it absolutely for certain more economical/sensible to have solar panels instead, even if you use inneficient ones to have their cost close to what a “blank” pane would cost. The electricity generated can be used in-place for *some* use, and further reduce the cost of the entire system. and converting the sunlight to electricity has the same effect as reflecting the light (it’s not absorbed by the earth).

          3. > “converting the sunlight to electricity has the same effect as reflecting the light (it’s not absorbed by the earth).”

            Not really Arthur, good as solar is all it does is convert some wavelengths of light to heat indirectly via the medium electricity with some useful work done. And the wavelengths the panels absorb without doing useful work just make them hot, so for local cooling just paint it white is actually almost certainly a better job.

            But if you can use the electric in place of fossil fuels its almost certainly worth it overall, substituting releasing lots of chemical potential as heat, rather inefficiently really, while producing lots of greenhouse gases in place of potentially capturing extra solar radiation (its possible the area you cover with panels would actually be worse than the solar panel, so may not capture any extra), some of which will then do the same work..

      3. Anything that harms plants, harms the existence of all living things on this planet. Life on earth, is based on complex carbon molecules. Where do we get the carbon, to function? Plants are the only living thing, that can take carbon, directly from the environment. Everything else eats plants, or something that eats plants. I like a warmer climate, moved to Florida about 35 years ago. Most of our food crops, like a warmer climate too. Plants also grow incredibly well, in a 700-900 ppm CO2 environment.

        This is our first inter-glacial period, that we had a language, writing, and the ability to record our observations. The past, the future, are all guess, speculations, mostly computer generated. It’s more of a ‘nerd’ version of video games, where they play with parameters, and wait for a hockey-stick chart. Then promptly pee their pants, because they destroyed virtual earth… We don’t know what normally happens during an inter-glacial. Correlation, is not causation. It’s weak science, exploited, for political, and media sensationalism. The planet has manage to keep it’s balance, a lot longer, than we first discovered how to burn stuff. The planet, has likely gotten slammed by some large space rocks, a few times, and recovered fine (we’re still here, and doing fine).

        1. But it is not the first inter-glacial period we have records of. We know all kinds of stuff about past periods due to ice core records. We know, for example, that we’ve not seen such releases of CO2 and other greenhouse gasses as such concentrations in previous inter-glacial periods. We’re having an effect on our environment. Our projections of what will happen in the future as a result are educated guesses at best, and due to the complexity of the situation, we cannot say for certain what the outcome will be, but perhaps it is best to err on the side of caution and try to limit our impact on a natural system that has functioned for millions of years, leading to our rise in intelligence so that perhaps it might continue to rise. Otherwise we face an even more uncertain future than we otherwise would. Better safe than sorry. I’m sure we’ve all experienced that, even if some of us never learned from it.

      4. But reducing photosynthesis, we reduce crops and therefore reduce food and nothing reduces CO2 levels like world wide famine. (Well if they don’t burn the billions of corpses, but then again who would be left to do it.)

  2. My concern would be that it reduces the sequestration of atmospheric carbon by biomass, getting us nowhere.

    Then if you tune it to specifically block IR… it will do that from both sides, it’s a screen and a blanket.

  3. The real problem as I understand it is that it makes us Aerosol addicts. Geoengineering of this kind means that our CO2 emissions could continue to increase while we apply the workaround, but if we stop applying it, then the effects of CO2 quickly bounce back (because the aerosols don’t stay in the sky for very long so we keep having to pump out this junk to cover for our other junk). So, it’s really just another global heating time bomb waiting to go off, if somehow humanity civilisation undergoes a collapse – or at least a crash significant enough to terminate the geoengineering, which will be increasingly likely over this century (even on the basis of what happened last century).

    So, it’s unwise from that viewpoint.

    “The heating effect of carbon dioxide persists for 10,000 years or more, absent unproven technologies for scrubbing carbon dioxide out of the atmosphere. In contrast, the sun-dimming particles in question drop out in a year or less, meaning that if you come to rely on geoengineering for survival, you need to keep it up essentially forever. Think of it as climate methadone.

    And if we are ever forced to stop, we are hit with dangerous withdrawal symptoms – a catastrophic “termination shock” wherein a century of pent-up global heating emerges within a decade.”

    https://www.theguardian.com/commentisfree/2021/apr/22/climate-crisis-emergency-earth-day

    1. If we built a space tether to get us to LEO easier/cheaper than rockets, which doubled up as a chimney, at what height would we stop having to pump CO2 up the chimney and the vacuum of space would just draw it out ?

      If said chimney went from ground level into space, can we just get space to act as a giant suction device along it’s length?
      We have Dyson sphere theory, what we really need is some sort of Dyson “hoover”

      1. As CO2 is denser than air you would have to pump it right to the top, and then you would get CO2 snow raining down and adding to the atmosphere anyway.

        Maybe instead run a rail gun and shoot solid CO2 lumps into space, exceeding escape velocity.

        1. However, the high altitude dry ice snow would probably block sun temporarily, so it would still do something.

          Furthermore, UV sunlight might break the CO2 molecules apart and release oxygen perhaps?

          But, either way it couldn’t scale up to volumes which would help our goal, even if it was beneficial.

      2. Vacuums don’t suck. Atmospheric pressure pushes toward gravitational centre of the planet. Putting a big straw into the atmosphere would just fill the straw to the height of the atmosphere.

        1. To both of you:
          Not terminating in the atmosphere but into space, past the atmosphere.
          Which I was told was a vacuum. Which doesn’t suck I suppose but gases would tend to flow into it.
          A closed pipe inside the atmosphere but extending past it and being pumped is no longer the same as the rest of the atmosphere.

          1. I think you haven’t realized that the “atmosphere” doesn’t have a strict boundary. It slowly fades out the further away from the earth you get.

            But that doesn’t change the first issue of your idea.

            Your chimney can extend into the vacuum of space, but gravity is going to tug on the gas equally within the pipe as it does outside it.

            The only reason vacuum can “suck” is because gas can move there if pushed there by something else, typically by the gas itself. Do note, the atmosphere is literally hundreds of km of piled up air.

            If we open up a vacuum chamber, the air doesn’t get sucked into it. But it rather gets pushed in by all the other air surrounding it. Not because it want’s to, or that it needs to, it is just the gravity tugging down on our literally hundreds of km of piled up air above, the air down at the ground simply can’t compete with that pressure applied from above.

            In the end, a chimney poking into space won’t suck away the air down at ground.
            (This is also really basic physics that I thought nearly everyone already understood….)

          2. Your theoretical pipe would not just have to reach past the atmosphere, but would have to extend beyond the Earth’s sphere of gravitational influence.

          3. Even if the pipe extends past the planet’s sphere of influence from a gravitational standpoint.
            That would still do nothing to the base problem that the gas inside the pipe and the gas outside it would be equally effected by gravity.

            Ie, the pressure drop as the altitude increases would be the same inside and outside of the pipe.

            The vacuum of space won’t suck out gas via the pipe regardless of its length.

          4. Wondering what the base wall thickness for a ~925,000 km long pipe would have to be (assuming iron or steel)….

            Probably have to punch in clean through to the other side of the Earth to anchor it… Would give you about a 1.4% anxhor depth…

            Might as well just add a 2nd pipe on the other side of the Earth to prevent throwing off our axis… It will still slow the rotation though by altering the moment of inertia…

            Probably would need to mine all the ore from the asteroids in our Lagrange points to supply all the material…

            Maybe would have to pull the Sun a little closer to power the pumps…. But that would make it hotter…..

          5. The OP said :

            “at what height would we stop having to pump CO2 up the chimney and the vacuum of space would just draw it out”

            I think y’all missed that bit.
            The question was at what point would we have to stop pumping the gas. The answer seems to be when gravity no longer affects it.

            But @ Alexander, your flippant comment about “basic physics” is amusing, when you didn’t even read the question properly and thus drew the wrong assumption.
            Capital D for Dave understood but you still argued with him as well.

          6. dave…
            Even if the pipe extends past the point of Earth’s gravitational influence, the air in the pipe would still not get sucked out into space.

            Since Earth would still pull the air inside the pipe towards the ground.
            The air pressure at the ground inlet would be about 1 atmosphere worth.
            As we go up inside the pipe, the pressure, ie air density, will decrease at a similar rate to what we would observe in the atmosphere outside of the pipe.

            When we reach the “edge” of the atmosphere outside of the pipe, we would also reach it inside of the pipe.

            We can continue to the point where Earth no longer has any gravitational pull, but that frankly doesn’t make a difference.

            In short, we don’t expect a space pipe to suck air for the same reason putting a pipe into the ocean doesn’t flood a mountain.

      3. Reading the replies to this was one of the most interesting times I’ve had in the comments section. Responses were done respectfully, and it was entertaining.

        Between this and the extraplanetary CO2 railgun, comment section is fun today

      4. I think we would want to get rid of the carbon from the CO2 not CO2 itself. We need to keep our oxygen. Just let trees grow harvest the wood and fire it into space (or store it on earth).

      5. So, if you measure the pressure at the bottom of a glass of water, and find it’s 1.1 Atmospheres and only 1 at the top, if you stick a straw in it it floods your desk due to the 0.1 ATM pushing it up the straw right? Nope.

    2. Another world war would easily help us forget to turn on the aerosol sprinkler system. Or any old country who controls the natural resources needed to continue the project could simply decide they want some bigger slice of whatever pie and hold us all hostage. Yeah, it’s a really bad idea.

      1. It started way before that. It started the first time someone said, “How can we save some money in our budget?” Then another bastard said, “Teachers make too much money, and schools cost too much. Let’s cut that.”

  4. It’s only after things get substantially worse that this area of research will get serious consideration. People don’t like the effect CO2 is having but they don’t want to do anything about it, they want someone else to do something. We will wait until it’s too late before actually do something.

    If you don’t believe me, just recognize that despite caring about climate change that it’s exceptionally unlikely you drive an EV.

        1. Yes, and I also have a car that I can use when the weather is bad, or the destination is further away.

          The rule of thumb on what is a reasonably priced car for the average person is one tenth of what the person makes in a year. The average person cannot comfortably afford a $35,000 a car – more like $3,500 if we’re being sensible. This is why somewhere around 70-80% of the sales of cars happen on the second hand market.

          IF I were to buy an EV, I would have to buy a new one, then rent a bigger home with a garage, pay to have a charger installed there, pay for the mandatory scheduled maintenance of a new car to keep the warranty, and then ten years later buy a new battery pack for it – all of which would cost at least 10x the amount I pay for my motoring right now.

        2. >the government could solve this by adding more tax

          I wouldn’t vote for such a government, and I’m willing to bet neither would more than half the people who, like me, can’t actually afford the alternative. If you apply the stick, you need to offer the carrot as well – stick and stick is just sadism.

      1. Even if you did would it actually be beneficial to the climate if you did?
        How many miles do you do, is your current vehicle in the higher miles per gallon range, easy and cheap to repair, how is your electricity sourced?

        For many folks an EV would just be grandstanding about how much they ‘care’ while actually being worse for the environment, particularly if their electricity isn’t clean or they don’t do many miles (in which case the embodied energy cost of building the new EV over its batteries shelf-life and the future refurbishment of that battery is so high its worse than burning fuel over those few miles in their old ICE car).

        Though equally for many others an EV would be a massive reduction in their environmental impact, and dirt cheap to run as well! Particularly if your EV is charged by green sources, and can act as a grid levelling battery feeding back some electric as the supply waivers (which across a whole renewable grid saves huge embodied energy costs in building dedicated grid levelling power stores), or you do so many miles that the embodied energy in building a new car is inconsequential compared to the driving energy cost (at least if the grid you get power from isn’t terribly terribly dirty so each mile driven is sufficiently better than keeping the old one going).

        1. You’re going to have to provide some sources with data to back up those claims. I can’t see how your examples can possibly outweigh all the oil pumping, refining, shipping, trucking, etc. that goes into an ICE vehicle’s fuel supply. You’re looking at the extended effects of EV, but assuming gasoline magically arrives at the pump with zero carbon footprint.

          1. Or all the mining, slurry pumping, refining, shipping, trucking, etc. that goes into an EV vehicle’s battery. Followed by all the mining, refining, shipping, trucking, etc. that goes into a power station to charge the EV’s battery.
            Plus the 8%-15% of transmission loses getting it there, plus the carbon footprint of power generation AND all the waste heat dumped into oceans or atmosphere and the knock on effect of pollution, waste ash and/or nuclear leaks. Or killing birds with wind turbines, or paving over green land with solar panels & the mining of materials to make them, or the damage hydroelectric does to river systems.

            There is no such thing as green. It’s just shades of less black.

            The utopian way of fixing this problem is nuclear fusion with no waste.
            Coupled to star trek transporters and replicators.

          2. > I can’t see how your examples can possibly outweigh all the oil pumping, refining, shipping, trucking, etc. that goes into an ICE vehicle’s fuel supply

            I’m not ignoring it at all – but that same fuel supply system goes into the electric grids, and not with out losses and extra carbon footprint – in many places even worse really dirty strip mined coal provides electricity too.
            As I stated it all depends on many variables, you would have to look at your specific situation in detail to get any idea of how green it would be for you.

            So take the recent Texas situation as an example when the entire state’s grid is busted so everyone that has power at all is using a generator that is immediately and obviously worse for going places than avoiding those extra losses converting the fuels chemical potential to electric to then stuff it back into batteries and finally extract it with looses at every step. Now if their grid was functional with the amount of wind power in the state its very likely the EV would be greener – at least some of its energy has come from green sources, surely enough to exceed all the energy conversion losses on the fossil fuel portion of its charge.

            But even then if you don’t actually do enough miles the EV may well not be greener – batteries have a finite lifespan (sure treated well its quite a long one but still very definitely finite) and major cost to replace, where an ICE that is at all looked after can last with very basic low impact spare parts – but how many miles you would have to do to reach that tipping point where the battery refurbishment is paid for by the greener per mile travel is still dependent on your power source (as heck it might not even be greener per mile if your grid is hideously dirty, and some are), and just how good your ICE is – many even rather old cars can do 40+MPG in the real world…

    1. My barbaric country gets its electricity mostly from dirty low-caloric coal which is abundant and near surface around here. Switching from hydrocarbon fuel to basically coal would be a step in wrong direction, IMHO.

    1. That’s a neat idea. I wonder if anyone has done the maths on what a cooler Venusian atmosphere would look like. Would we just flood the surface with sulphuric acid? Is there enough calcium in Venusian rock to begin to reduce the acidity? Could be interesting.

      1. Well Venus’s atmosphere is mostly CO2 and H2S04 and we’re already converting CO2 into O2 on Mars, figure out a way to convert H2SO4 to H2O and O2 (hide the S under the carpet?) and Bob’s your uncle, long days on Earth 2.

        1. The H2SO4 is exactly why I was wondering about calcium, on Earth we have plenty of CaCO3 which could neutralise a lot of acid, but plenty of it has a biological origin. I don’t know if there was primordial CaCO3.

    2. That’s a very good idea. If we extinguish all life on venus, we haven’t done much of anything. If we do the same on earth, that’s going to be hard to undo.

  5. Maybe instead of blocking the sum, it would be possible to reflect the sun’s ray at the poles. That would reduce the quantity of calories absorbed by the Earth, and help with climate change as well. For example, you could have a very, very thin film or paint or powder, that you disperse on the ground or the sea near the poles, and that would cause the ground/sea to cool down and freeze. That way you have ice instead of what you normally would, and it would help with storing water at the poles instead of the oceans, and therefore help with reducing the rise of the sea levels. The idea here is that you only need an extremely thin film to achieve this effect (or powder, or paint). And so you would not need large quantities of materials to have effects/help with issues. For example, a 10-atom thick layer of reflective material could cover square kilometers with very low weights/volumes of materials. I can do the math if somebody is interrested.

    1. If you can manage to reflect/radiate enough energy at the poles to drop the local temperature to freezing so more ice forms, that would be very impressive and help significantly as the new ice is good at reflecting anyway…

      But I don’t think its particularly possible unless you can also somehow greatly reduce the ocean currents, all that flowing water will keep the temperature too high. And slowing the ocean currents is almost certainly a terrible idea with how little we really understand the oceans, so even if we could do it we probably shouldn’t… Though if you manage to create a radiator surface you can sit on the ocean all the flowing water will bring energy to the radiator.

    2. Mayyyybe…

      I wonder if you could do it by changing optical index of air so it diverges rays out of the atmosphere again.

      Though the arctic and antarctic circles still have ecosystems that would get screwed up.

    1. The link between aerosols and the ozone layer was the propellant used in aerosol cans. Chlorofluorocarbons (CFCs) have relatively high boiling points, and are less flammable than other similar propellants. That’s also why they were excellent as refrigerants.

    2. Exactly, look at the last time we as a species went off half cocked on an aerosol based invention. CFC’s looked perfect, non toxic, safer and better than previous refrigerants, shame it turned out to be a massive mistake which caused a hole in the ozone layer. I think this is one of those ideas that should never leave the drawing board, lest we find out in 10 or 20 years time that someone forgot to carry the 1 and everyones doomed as a result.

  6. This is crazy, not fixing the problem at all. It’s not only the additional greenhouse gasses that we need to be worried about but all the additional energy dumped into the atmosphere. Most of all the energy produced by gas, oil, coal even fission and fusion ends up as extra heat in the atmosphere. The only solution is to intercept and use the sun’s energy on its way to being heat. The CO2 needs to be reduced by restoring trees and peatlands then storing away the solid carbon somehow.

    1. sooo, if you reply to a comment that got deleted in the mean time / 10 Censored at this moment / your reply will still be posted under the main thread making it looks (even more) stupid and out of place. Not ideal.

  7. I think it’s nuts that people find this sort of research to be controversial.

    I don’t believe anyone is suggesting it as plan A. It’s about being prepared with a plan B.

    “We need to fix the problem not the symptoms” – Agreed but what if we fail? This could be our only alternative and/or a way to buy the time we need.

    “It will take away focus from fixing the problem” – No, we are a species of over 8 billion people with diverse resources, talents and ways of thought split into a ridiculous number of nations and all sorts of organizations. As a whole we are naturally a lot better equipped to multi-task than to focus on one single problem. I doubt this research will take anything at all from our focus on fixing global warming properly.

    We should have someone at all times looking at every possible solution to every problem humanity faces, big or small in order to produce the best possible future. Putting everyone on the same project is just “too many cooks” and ensures we will get nowhere.

    “Unforeseen consequences…” – Which should be studied as much as possible to make them not un-forseen. But if it comes down to it where we know there are bad consequences of not acting then we need to measure the possibilities of unforseen consequences with the certainty of known consequences of not acting and choose accordingly. Nobody is presenting this as the ideal situation.

    “But we just have to do this one thing, plant more trees, build more solar plants, etc… and it will all be fine” – If you think it’s that easy you haven’t been paying attention.

    Again, nobody (that I know of) is advocating for a massive geoengineering project to go into effect today. Nobody considers such to be the best possible future. But if we fail to fix the problem the right way in time we could find ourselves moments out from a tipping point with massive consequences. Having already researched aerosols and/or other geoengineering projects as an emergency backup only increases the odds that our children and grandchildren can have good futures.

    Put another way, it’s better to not burn your house down but that doesn’t mean one shouldn’t have fire insurance.

    1. A few problems with your arguments, but overall, I agree this can be kept as a final stab in the dark, save ourselves or die a horrible fireball death type of plan.

      ““It will take away focus from fixing the problem” – No, we are a species of over 8 billion people with diverse resources, talents and ways of thought split into a ridiculous number of nations and all sorts of organizations. As a whole we are naturally a lot better equipped to multi-task than to focus on one single problem. I doubt this research will take anything at all from our focus on fixing global warming properly.”

      I have no idea who or what you’re basing this opinion on, but my opinion of humanity is not NEARLY as optimistic. We constantly do the least amount of work required then forget about the problem. Did you live through Y2K? Turned out to be a non-issue, but the same human behavior was on display. We’re still having troubles with dates on things. What about the anti-vax crowd? We had trouble with disease, fixed it, then decided we like getting deathly sick better. Wtf?

      ““But we just have to do this one thing, plant more trees, build more solar plants, etc… and it will all be fine” – If you think it’s that easy you haven’t been paying attention.”

      This is in opposition to your above opinion. The same people who are so good at multitasking think that we only have to perform one task? I don’t think anyone who knows anything feels this way. These are all ideas that will help, but not all we have to do. We’ve been cutting forests worldwide for centuries, and in the last century, we’ve really cranked up the chainsaws. All our oil is primarily from vegetation. Killing all the vegetation will not only make sure nothing sucks up all that carbon we’ve released into the air, it will make sure that there are no future oil deposits. Should we laugh or cry?

      “Again, nobody (that I know of) is advocating for a massive geoengineering project to go into effect today. Nobody considers such to be the best possible future. But if we fail to fix the problem the right way in time we could find ourselves moments out from a tipping point with massive consequences. Having already researched aerosols and/or other geoengineering projects as an emergency backup only increases the odds that our children and grandchildren can have good futures.

      Put another way, it’s better to not burn your house down but that doesn’t mean one shouldn’t have fire insurance.”

      Now we agree again. Blocking out the sun is a very bad idea in my opinion, but it might be better to have as a back up than nothing. Nothing is also a very bad idea, and currently that’s all we effectively have.

      1. “As a whole we are naturally a lot better equipped to multi-task than to focus on one single problem. ”

        A little clarification, reducing our energy use and not cutting down forests IS something we all have to do. Obviously if one group releases enough CO2 or cuts down enough forests it doesn’t matter that everyone else does not.

        “I have no idea who or what you’re basing this opinion on”

        I’ve never seen anyone present evidence that money or manpower currently being spent on reducing CO2 or researching geoengineering with Aerosols is a zero-sum game. I’ve never read an article stating that some think tank that was working on better solar cells, or some under construction wind farm, a tree planting project or any other such program was de-funded in order to start a geoengineering project. Yet every time the idea is mentioned some people post that we shouldn’t be working on that because we need to be 100% focused on CO2 reducing measures like those instead. Until I hear of such movements of resources I think the burden of proof is on them.

        “This is in opposition to your above opinion. The same people who are so good at multitasking think that we only have to perform one task?”

        I don’t see a conflict in my statements at all. I was saying that as a world we can and should focus on multiple issues. But people talk like working on a different problem or even a different solution to the same problem automatically means that their favorite problem and solution is automatically neglected. The world’s too big for us all to be doing the same thing.

        Then I shifted to responding to another common comment type. Comments that follow the general pattern “Don’t bother with that, all we have to do is ____ and the problem will be solved.”

        I think you were responding to that when you wrote this: ” I don’t think anyone who knows anything feels this way. ”

        There was a specific comment I was looking at when I wrote about that. There are so many now I’m not entirely sure but I think it might have been the following:
        “Reyni says: April 26, 2021 at 7:52 am Just recreate forests…”

        To that one specifically, I’ve read a lot of articles that said when the number of trees we would have to plant to get back to natural CO2 levels is calculated it is an impossible number. But that doesn’t mean we shouldn’t do the best we can to rebuild forests. It just means that a real solution is complex and will have several parts.

        1. I’ve read a lot of articles that said when the number of trees we would have to plant to get back to natural CO2 levels is calculated it is an impossible number.

          So… you read horrible articles that lie to you. And? What on earth makes you think anybody values that knowledge? Just self centered?

    1. Also a device used by Arthur C Clarke in Childhoods End (1953).
      Kim Stanley Robinson also used it in 2312, though that was Venus, where there’s an amusing description of bulldozing the resulting carbon dioxide snow.

  8. Theres also the theory that we could put a reflector in between the sun and the earth and use that effect the % of solar energy reaching the earth. Also an engineering problem coming up with a structure large enough, but placed far enough away between the earth and the sun, a few %age points might be doable.

  9. I’m somewhat surprised nobody has mentioned the idea of what is somewhat alluded to in the article’s image: a solar umbrella.

    Essentially, orbit a giant solar sail (which can use some of the energy reflected to move itself) which casts a moon-ish eclipse across uninhabited surface (eg the ocean). Ideally the sail would be like “blinds” that you can open and close at will, so you aren’t freaking out animals 1x a day with an eclipse, and you can “turn it off” ie let the sun through if anything isn’t working out.

    Super absurd engineering challenges aside, if you could block out some fraction of total light impinging on the world, theoretically it’s just a matter of determining how close to unity that fraction must approach to decrease the overheating to zero.

    Montie Burnes, anyone? ;)

  10. I worry about the effects on the oceans and their convection mechanism that drives the known currents.

    A shift could be far more disastrous than what we have now…

  11. If you like metal and sci-fi, I recommend the story of Forever / Alpha, told across the albums made by Ayreon: how they caused several natural disasters, triggered at least three planet-wide mass extinctions (on different planets!), and at one point simply completely blocked their own sun: https://www.youtube.com/watch?v=uozt4N72a5U

    All because they couldn’t stop “fixing” their problems with more problems.

  12. One thing that would greatly improve our outlook is to use our technology to get the water cycle on this planet stabilized. We have floods in one area, drought in another. California has shamefully wasted the water resources there to a point where the once thriving forest areas are now drier than ever. Then they complain “it’s climate change” when there’s a wildfire.

    Yes, many elements of “climate change” are due to humanity’s choices. But the petroleum and coal burning are only a fraction of the reason. We need to use what we know to mitigate water resources to areas that are parched, allowing green areas to thrive. We need to use carbon neutral technology like next gen nuclear to provide drinking water for our growing population and to water areas that need it.

    If we’re going to waste viable fresh water reserves, and not find some way to restore the areas that we damage as a result, we are doing more damage faster than burning petroleum for decades.

    The thing is, we know how to divert rivers. We know how to move water great distances. The only thing we need to do is make the collective effort to do this.

    If you make the Sahara a green area like it was in the distant past, you’d see no problem with the global temperatures. You’d also provide that much more useable space for our species.

    it just takes a force of will. Which unless there’s a profit to be made we sorely lack as a species.

  13. It is not required, incredibly dangerous (if it is the non-reversible options) and even potentially inequitable. The people suggesting such things should be treated as if they were criminally insane, because they are.

        1. Yes, you are right, my bad, indeed, when I went to CERN, nobody was in charge of anything, anyone could just do anything.

          I just walked in there, and started using the LHC to roast marshmallows for a few hours. Fun times. Who knows, I might have caused some scientific advancement too! Maybe. Who’s to say, right ?!

          It’s so great that science is only a method, it’d be so inconvenient if there were limits on who is in charge of what.

          Joking aside, your fallacious answer makes me doubly glad you are not in charge of any science…

          1. LOL somebody is in a tis because they made a fool of themselves and forgot what science really is. The people “in charge” of CERN don’t operate it anyway, their minions do.

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