Could Moon Dust Help Reduce Global Temperatures?

The impacts of climate change continue to mount on human civilization, with warning signs that worse times are yet to come. Despite the scientific community raising an early warning as to the risks of continued air pollution and greenhouse gas output, efforts to stem emissions have thus far had minimal impact. Continued inaction has led some scientists to consider alternative solutions to stave off the worst from occurring.

Geoengineering has long been touted as a potential solution for our global warming woes. Now, the idea of launching a gigantic dust cloud from the moon to combat Earth’s rising temperatures is under the spotlight. However, this very sci-fi solution has some serious implications if pursued, if humanity can even achieve the feat in the first place.

Cloud of Protection

A new concept involves spraying dust from the Moon towards the L1 point between the Sun and the Earth. This would potentially be much more efficient than launching billions of kilograms of dust from the Earth’s surface by conventional methods. Credit: Gregory H. Revera, CC BY-SA 3.0

The idea behind the proposal is simple. By reducing the energy input into the Earth from the Sun, we can better account for the Earth’s increased insulation in recent times. There are a variety of ways to achieve this, with the emission of sulfur dioxide aerosols an area of active research for many scientists. However, moon dust could serve in a very similar role, if properly distributed around the Earth.

Researchers have explored methods such as creating a large singular cloud of dust to protect the Earth. Dust particles floating in a cloud between the Sun and the Earth would help reduce the planet’s temperature by absorbing heat from the sun as well as scattering light away from the Earth. One study suggested that to effectively block enough sunlight to halt climate change, over 10 billion kilograms of dust per year, perhaps sourced from near-Earth asteroids, would need to be positioned at the L1 Lagrange point. Here, the gravitational tug of the sun and Earth cancel each other out, allowing objects to remain stationary.

However, continuous maintenance of the cloud would be necessary due to particles in the cloud being disrupted by the solar wind, gravitational effects, and radiation pressure from sunlight. A further problem is simply one of scale; the weight of dust required is over 700 times greater than the total mass humanity has launched into space to date. Getting all that dust into the right spot in orbit would require a huge number of launches; a logistical effort far eclipsing anything humanity has done before.

Researchers explored a variety of materials, both engineered and naturally existing, for their capabilities in serving in a dust cloud to shield the Earth from solar radiation. Credit: Research paper

Another research paper published earlier this year in PLOS Climate suggests an alternative method. Thanks to recent computer simulations by Benjamin Bromley and his team at the University of Utah, a promising approach might be directly launching a steady stream of dust from the moon’s north pole on ballistic trajectories towards L1. These simulations indicated that each particle could block sunlight heading to Earth for approximately five days before scattering throughout the solar system. This offers a practicality benefit, too. The short-lived nature of the cloud means that it could be varied in its density or removed entirely in just a few days in order to control the intensity of its shading effect.

Of course, the logistics of deploying such a massive amount of dust would still remain a challenge. Bromley’s calculations are based on somewhat idealized particles, which would be manufactured in situ on the Moon. We lack the technology to do that right now, as well as the technology to launch these particles towards L1. Bromley hypothesizes that a railgun would be an effective method, given that it could be powered via solar panels placed on the Moon itself. It would, at the very least, be a far more efficient method than launching 10 billion kilograms of dust from Earth itself.

Hazards of Geoengineering

In recent years, scientists have noted the cooling effect of sulfur dioxide emissions from the shipping industry. Despite this beneficial effect, there is reluctance to pursue this as a geoengineering method due to the risks involved. Credit: Jin, et al, 2018

While these efforts sound promising, if far-out, there are caveats. For starters, it’s uncertain whether such a massive undertaking would be worth the effort. Even if we had the technology to create such a dust cloud, the effects may not be so simple. Even if it reduces Earth’s average temperatures, it could change sunlight distributions on the Earth in such a manner as to influence things like ocean currents, rainfall patterns, and other climate phenomenon. This could drastically impact agriculture and the livability of inhabited areas, with potentially disastrous effects for the global food supply. Global climate systems are so complex that it is difficult to model such diffuse effects with any real certainty.

The most significant concern, however, is the commitment this method requires. If we start geoengineering to counteract greenhouse gas output, it may become necessary to make it a near-permanent solution. Politically, any such sun shield could be used as a convenient excuse for halting emissions reductions. This could then leave Earth dangerously exposed to rapid temperature rise if the geoengineering effort fails in future. Ideally, such measures would only be used as a temporary solution to buy us more time to implement proper emissions reductions to return Earth to a more sustainable footing.

Given the global impacts of such geoengineering projects, comprehensive studies involving multiple countries, overseen by bodies like the United Nations, are imperative. Many uncertainties, from inaccuracies in dust deployment to potential damage to satellites, need thorough examination. While many oppose geoengineering as a foolhardy distraction from emissions reductions efforts, others counter that we should study these ideas lest we need them in a pinch.

In any case, the idea of using moon dust as a geoengineering solution underscores the urgency of our climate crisis. As tantalizing as the concept is, a lunar dust shield must be pursued with caution. We may be opening a proverbial Pandora’s Box: once we start, we may find ourselves locked into a solution that we have to maintain at any cost, whether we like it or not.

67 thoughts on “Could Moon Dust Help Reduce Global Temperatures?

      1. L1 is between the Earth and the Moon, and is unstable. A significant portion of anything left there is eventually going to fall to Earth or the Lunar surface, or else get kicked out into a Solar orbit.
        It’s definitely not 4x farther from the Earth. The only stable Lagrange points are roughly the same distance of the moon, in front of and behind it in its orbit.

    1. Yeah. I know it is old, but these idiots should go and watch Highlander. Very good example of unintended consequences. Hopefully they’ll learn something and think twice. Most biological life on earth (like in say “us”), needs the sun to survive.

      1. Can you please explain to which “unintended consequences” you are referring to. I don’t want to watch the whole movie over and over again trying to figure out what you might mean. Problem one, my VCR and the tape with the movie are somewhere in storage, might take days to find it. Problem two, I might not be able to find the scene you are trying to refer to or perhaps might not be able to connect the point of a mythical slasher movie with the point of moon dust thrown towards earth. Please enlighten us.

        Regarding “unintended consequences”, would you be able to compare the “highlander” movie with “There’s Something About Mary” ?

        1. You actually have to watch all of them to make sense of it, but it is the one where they covered the earth in a shield to reverse climate change…then the earth started to die. It might be just fantasy, but not so far fetched…

      2. You mean the 1986 fantasy movie about immortal swordsmen in Scotland?

        The problem of using fantasy as reference here is that nothing in a movie happens because something else happened earlier in the film, but because the writers wrote it that way.

        1. Some better example – Four Pest Campaign. China declared war to sparrows as those were eating grains therefore were considered to be pests. They won the war – sparrows stopped eating grains (because none left). Consequence: rapid surge of insects that devastated crops resulting in great famine.

          Using fairy tales to educate people is a common practice. They serve same purpose as analogies. Particles are not like cats in a box, current is not like water, you should beware of strangers even if they are not wolves and you don’t fight global warming by swinging a katana ;)

    2. Yeah, so fun fact: We’ve been geoengineering the earth’s climate to make it significantly cooler for over 200 years. We stopped a couple years ago by accident.

      Turns out sulphur-heavy fuels used in shipping have been _significantly_ lowering global temperatures through cloud-seeding, since the beginning of the industrial revolution. The climate is seriously more damaged than we ever thought it was. We’ve received a good 15+ years of warming in the last 12 months and there’s no sign it’s going to stop.

      The unintended consequences are here. It was unintended that global trade would mask most of the effects of climate change. At this point we know more about the behaviour of an artificially-cooled world than one left alone.

      The best we can do is try to make up the difference for the accidental geoengineering we’ve been doing, to buy time and try to figure out our next move. We literally can’t afford not to. The only choice we have is how we do it. We could go back to burning large quantities of sulphur fuel, but that would drive acid rain and ocean acidification.

      For more info, see Hank Green:

  1. >Politically, any such sun shield could be used as a convenient excuse for halting emissions reductions.

    That’s the entire point of it – or rather that the world isn’t actually reducing CO2 emissions despite all the money spent in windmills and whatnot, and the continues increase in emissions come from countries that don’t want to play ball because they want to increase their living standards – like China and India – so there’s nothing else we can do.

    Well, there is, but that would be a whole different can of worms.

    1. We will avoid effective solutions (because they look like mass genocide and famine and nuclear war) for decades and decades until nature forces our hand. Simply ceasing to subsidize the feeding of excess biomass. It’s not going to look pretty and even the suggestion that our actions might have logically-determined conclusions gets you called certain German names from the 1930s

      1. And China has four or five times the population of the US, so your point is?

        The reason for the low emissions is not a virtue of the Chinese, but due the poverty of most of the population. When the Chinese economy grows and the living standards across the entire population approach the US, the people can afford and will consume more energy – and produce more CO2.

          1. Missing the point there.

            Even if you level the difference per person, while the US emissions would go down by a quarter, the Chinese emissions would increase and add four times the US CO2 emissions as they up their living standards – and no other country has the authority to demand that they don’t.

  2. Warmer climate and more CO2 enables plant growth on an exponential scale. The world, especially Africa, Middle East, Asia and European Union is facing a food crisis that in the next 20-30 years will bring massive famine resulting in loss of population on a scale not seen since the Black Death. Imagine if humanity could turn all those vast wastelands of Siberia into arable land. We could feed everyone basically for free. No more wars and hunger.

    1. Great… but we’d lose a large portion of our existing farmland to higher sea levels. You’d also be making a large bet on the stability of the climate in the equatorial zones. We’re already seeing desertification in many currently tropical places, if the Earth is hotter we might be moving the habitable zones toward the poles.

        1. They’ve only been able to do that with the help of some unusual geography, and they’ve not had to do it while under pressure from people who already live in the undersea areas.
          I’m sure it would be possible with enough foresight, funding, and support to put up SOME dams. I just don’t see it happening fast enough, big enough, or in the right places.

      1. Until recently it was economic to grow certain budding plants indoors under lights. (Economic because lawyers are expensive.)

        Often with CO2 added, for growth.
        Granting that’s one plant and there is a limit for CO2 levels, but it’s not speculative.

        Actual hort majors could give you a list of plants/CO2 levels. There is likely a pattern and those plant nerds have likely worked it out.

        What does ‘a net decrease in nutrients following an increase in it’ even mean? Nutrients left in the soil?
        Weasel wording, misquoted or both.

    2. “Warmer climate and more CO2 enables plant growth on an exponential scale.”
      Only if you also exponentially increase fertilizer, water, and pesticide usage. And then only for certain crops(many produce badly in hot weather, ask a tomato farmer. Plus you will need to move existing farms and infrastructure to new areas and the current path is that the new climate is more erratic, which is bad for farmers, so : No.

      1. And if you think you could just convert all of Siberia into a big soybean farm to feed 20 billion people without utterly NUKING the environment, you are an insane human-biomass-maximalist zealot.

      2. You have to do both feeding and culture-change (and increase of living standards), so the people won’t spit out babies like on a conveyor belt. The West has actually problems with average aging and being below-replacement-rate, a different can of worms.

        Ideally, over couple generations, the total population decreases somewhat, to more manageable level, in a nonviolent “natural” pace.

      1. Let’s say for a second that what you say is true… You might see a $200/year saving on heating, but what about cooling? What about increased insurance rates due to increased weather anomalies? What about cost of food increases due to lower yields as farm lands become desert? I suspect that your $200/year quickly gets wiped out. I’m sure that if you have kids they’ll greatly appreciate that you saved that $200 when they’re struggling to survive in a dyeing world.

    3. “The world, especially Africa, Middle East, Asia and European Union is facing a food crisis”

      I live in EU and see no problem related to food other than more people heading towards “size plus”.

      “Imagine if humanity could turn all those vast wastelands of Siberia into arable land. We could feed everyone basically for free. No more wars and hunger.”

      First of all – Siberia is not such a wasteland.

      Second – we have much more “wastelands” like Alaska. Or we could turn any state in US into such area – US have enough states and could sacrifice one – just transport people out of it.

      Third – we already turn a lot of areas into arable areas and it often end up very bad.

      Third – whoever controls that area, controls food supply chain and would have to defend himself against terrorist, dictators and democracy importers (who would portray him as terrorist or dictator). Fair food distribution would be impossible. Even now we would rather destroy remaining food rather than share with Africa/India. And we waste enormous amounts of food not even planning to feed homeless at our own country – we would rather burn, drawn or dispose fresh food if was impossible to sell then give it away (even for half price) to anyone.

  3. Frankly, while it’s a noble goal to reduce emissions to the point scientists want, the ability to actually do that is near impossible. Most countries could go back to living like the Bronze age, yet other countries wouldn’t stop. Giving up our entire society would not make enough change. Instead of using Dixie cups to scoop water out of the sinking Titanic, we need something huge.

    1. “The Dixie Cups (formerly known as The Meltones) are an American pop music girl group of the 1960s.” – I may not have found the right Wikipedia article to understand your reference.

      Try again. Oh, a paper cup. Do you really refer to paper cups as Dixie cups?

  4. Pumping billions of tonnes of fossil fuel derived CO2 into the atmosphere is already our most significant Geo-engineering project and we need to firstly weigh up whether it’s a good idea to add to it with another, given the likelihood of a global scale stuff-up.

    The second most important issue, besides the ones listed in the article, is that all Geo-engineering projects could most easily turn into a licence for the fossil fuel industry to continue as usual. Given their ability to manipulate governments, public opinion and the IPCC itself (COP28 is being hosted by an oil CEO) this is also the most likely scenario: it wouldn’t fix global warming, but it would provide more profits for polluters.

    It may, however make sense when the fossil fuel industry’s ability to burn their product been dismantled. We’ll still need to cut CO2 (420ppm now, around 550ppm by 2050) back to 350ppm and that means going carbon negative.

  5. I am a big fan of “be careful of unintended consequences” but unfortunately the unintended consequences of our current course is turning large parts of the planet into scorched wasteland incapable of supporting any life, mass migration and starvation, war, weather and agricultural disasters, and possibly the collapse of technological civilization. We may need to take some risks here.
    While it is probably true that abatement by geoengineering will be used as an excuse to avoid hard choices the same can be said of abatement by renewable energy or electric vehicles, any improvement will be seized on by those with a vested interest to delay their reckoning. I am also less worried about that because the economics have come around. It is now apparently cheaper to build new solar and wind than to operate fossil power plants, heat pumps are cheaper to run than furnaces, etc. Steel making and ammonia seem to be on the verge of electrification, which only leave air travel and concrete on the hard problems list.
    On the other hand nobody has come up with an technically/economically sensible carbon sequestration system(except for better agricultural processes). Until that happens a carbon neutral world(however long it takes to get there) is just an oven that is getting no hotter.
    And frankly, the longer we wait to get started the harder it is going to be to do large, complex, technical things, as more and more resources are needed just to keep our heads above water while we circle the drain.
    So here’s my proposal for a revised Artimus project: get on the surface fast, poles first then an equatorial outpost with a mass driver and an aluminum mine/smelter, the aluminum can be made into foil balloons either on the surface or at L5, they can be fitted with O2 cylinders for inflation and thrust packages(solar electric?) and electronics for station keeping, then pushed off to L1 in batches with tugs, they inflate on arrival and each lasts years before it’s fuel runs out. You can even include an emergency self-destruct. Between NASA and SpaceX I bet we could start launching in 5 years.

  6. Stratospheric aerosols are a tried-and-true alternative. Lots of prior art done there, namely by volcanoes. So we already know what will happen, because it happened so many times in the documented past. Start there, preferably with carbonate particles instead of sulfates.

    Use that to buy time. Continue for limited time with fossil fuels, keep energy cost for the transformation down enough, use the time bought for massive scaleup of thorium-based energy, with option to switch to fusion once ready.

    Everything ends up with energy. With enough inexpensive energy we can distill mountains for metals, we can mine the deepest ocean bottoms, even the asteroids. And several ways of atmospheric CO2 removal can then be done at leisure, with corresponding scaledown of the aerosols deployment.

    With enough energy and materials, we can replace reliance on arable land with modular vertical farms, or printing living tissues and then letting them grow into a meat or a vegetable. Better controlled environment, no bugs, no weeds, no pesticides needed; each city can have a couple towers with a reactor nearby, and feed itself. Scalable, and would work even on Moon, Mars, Titan…

    Of course instead of that we get carbophobes imposing duties and taxes and more paperwork and blabbing about “moral hazards”.

    1. I bet it’s return to Earth through all our orbital equipment at almost escape velocity would be equally unproblematic. Space hardware does so often miss out on the opportunity for a good tickle 🙄

  7. OFFS, we need to reintroduce heavy sulfur content bunker fuels to transoceanic marine traffic. This was what was happening in the north Pacific until 2020, and it was offsetting climate change by seeding cloud cover and increasing the albedo (reflectiveness) of the north Pacific.

    We’re in deep shit as it is…

  8. Aren’t Lagrange points inherently unstable? like putting a marble on top of a big sphere- sure it is “stable” in that if you get it just right it’ll stay there but any tiny perturbation and it just drifts away? Unless I’m mistaken (it happens a lot) there isn’t really a good way to keep all the dust there at the L1 point.

    1. While it’s not the best, it’s still a distinctly better bet than our beloved politicians. Their competence in solving difficult issues is outright legendary, together with their agility in applying the solutions.

      At the end, it’s an engineering problem anyway.

  9. If you can make this movie without Vin Diesel or Duane Johnson I will watch it.
    Bonus points if Micheal Chiklis or Bruce Willis can make an appearance.

    Also a mandatory Jeff Goldblum character: “Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should.”

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