This month, a paper revisited an attention-grabbing solar geoengineering idea – mining the moon. The theoretical astrophysicists Bromley, Khan, and Keyon (2023) suggest that ejecting moon dust into space could shade the Earth from a certain amount of solar radiation. The ideal outcome is to reduce the solar radiation reaching the Earth’s atmosphere enough to fix global temperatures at a safe limit.
While there are clear theoretical outlines of how this could be achieved, the technology is unlikely to be feasible in the next few decades. Solar geoengineering is considered a ‘magic bullet’ solution for climate change, requiring little attention to the economic systems and environmental processes that produce greenhouse emissions. In theory, it would allow us to control the temperature of the Earth much more directly and rapidly than methods such as emission reduction or carbon resource management. Moondust is not the only way to achieve this.
As outlined by the Carbon Brief, there are six commonly proposed techniques for solar geoengineering: aerosol injection, marine cloud brightening, increasing the albedo of the Earth’s surface, creating an ocean mirror, thinning clouds, or putting sunshades up into space.
Space is considered a safer option for geoengineering than the Earth’s atmosphere. Technological ideas such as putting sunshades up into space–––which might take the form of one giant reflective screen, or a swarm of smaller satellites, contributing to the Kessler effect––––makes moon dust seem an easier solution. The paper proposes launching the dust near the Earth-Sun L1 Lagrange point, where the gravitational and centrifugal forces of the Moon and Sun balance one another. The dust would be held in a relatively stable position, although radiation pressure, Poynting-Robertson drag, and solar wind would all mean the dust could drift away within a few days to a week. Given the effort it would take to mine the moon and shoot the dust biweekly from an orbiting platform or straight from the moon itself, this idea will remain theoretical for a while.
Yet ‘moonshot’ geoengineering ideas such as this hold significant implications for how we imagine climate solutions. Space is often seen as a final frontier in which technocratic solutions are not only preferred but entirely necessary. Moreover, outer space is separate enough from Earth that these ideas appeal to a certain stasis of carbon abatement efforts on the planetary surface. But many climate scientists emphasise that solar geoengineering should be used alongside other methods – not alone. It has a rapid speed of effect, making it an insurance option for catastrophe management in the event rapid tipping points are induced by climate change. Other methods to reduce the harm caused by climate change, such as carbon dioxide removal, emission abatement, and adaptation, take time. The ‘lag time’ between emissions production and their forcing effects on the environment can range from several years to decades. This also means reducing emissions now will not stop rising temperatures for several more years. Should we reach a catastrophic tipping point that fundamentally alters Earth systems, such as the Amazon rainforest dieback or the collapse of Greenland’s ice sheet, this could have disastrous consequences. Therefore, it is important to acknowledge the solid technical argument for solar geoengineering with moon dust.
The social and ethical ramifications of this technocratic solution are essential to consider. Who will control the technology? Will it be a privately owned or state enterprise? Will power blocs emerge as a result, given the unequal capacity for states to engage in global agreements? As with all anthropogenic interventions, what new patterns of social inequality and environmental risk will arise from the inevitably uneven effects? These questions assume that the technology itself is sound and that there are minimal unforeseen consequences of lampshading the Earth. But perhaps the underlying philosophical question is this: is this ‘moonshot’ nothing more than a distraction from the pressing need for carbon emissions abatement?
One of the potential drawbacks of pursuing geoengineering solutions such as the moon dust idea is that it could make states and companies more reluctant to reduce their carbon emissions. It is seen as a quick-fix solution for the problem of climate change, requiring little attention to the economic and environmental processes that produce greenhouse emissions. If geoengineering is seen as a matter of state security or a space for profit, these solutions could be trialled and utilised in the next few decades. The social impact of geoengineering on politics and governance could be just as great as the consequences of geoengineering itself.
Ultimately, the complexity of climate change means we cannot solve its often unpredictable effects with merely an emissions tally, a radiative equation, or moon dust. No matter what, we must begin carbon reduction to keep the risk of climate catastrophe as low as possible for future generations. But we still need social and cultural changes to create resilient networks to protect the most vulnerable from climate change. Actors launching geoengineering solutions will only see the crisis: not the social consequences of the solution. If all it would take to secure international security was a global ‘consensus’ of the usual kind and the push of a button, would it be unethical to refuse to do so? Mitigation and adaptation are just the beginning of a bigger picture that includes the social and cultural changes necessary for real, equitable resilience. It is possible for geoengineering to be both a solution and a distraction. Debating the binaries of climate approaches could take us up to the point where all we can do is press the button.