Cooling the Earth with Moon Dust – Clever Climate Solution or Making Frankenstein’s Monster?

There is reason to believe that the year without summer following the 1816 eruption of Mount Tambora inspired horror fiction frankenstein and vampireSome also believe that Edvard Munch’s famous 1893 painting “The Scream” was partly inspired by the view of the sky after the eruption.

A sufficiently powerful eruption can send sulfates and other aerosols into the stratosphere, cooling the air there. This fact has motivated human efforts to artificially spray aerosols into the stratosphere to slow global warming, with occasional support from the U.S. government and others. The US government currently officially supports research into solar radiation management (SRM).

In a controversy late last year, a private company called Make Sunsets used balloons to release traces of sulfur dioxide into the stratosphere in an effort to market “solar dimming” as a way to offset carbon emissions. For many researchers, this event is an important red flag of the colonization of public goods such as the atmosphere by private actors.

Smoke rises from a volcano on the Italian island of Stromboli on July 3, 2019.Image credit: ANSA via AP

moon dust

The latest media coverage on this comes from a paper recently published in the journal PLOS Climate February 8. US researchers have proposed that billions of tons of dust could be launched from the moon to a Lagrangian point – the point in space where the gravitational fields of the Earth and the sun cancel each other out. The feat is clearly hampered by serious technical and economic challenges, but there is interest.

The science of the consequences of volcanic eruptions is well established. Aerosols in the stratosphere, especially radiation-scattering aerosols such as sulfates, do have a cooling effect.Here’s What Leads to “A Year Without a Summer”—But Forget other Consequences of the same eruption. Cool summers have led to widespread drought across the globe, causing crop yields to plummet, leading to disease and hunger. Many climate models have demonstrated that reducing the amount of incoming sunlight with stratospheric aerosols produces similar results.

Some recent studies suggest that the resulting droughts would be less harmful and that the GDP of most countries would be positively affected by this SRM approach. But we should remember that even the most advanced climate models can only guess at the temperature response to changes in solar radiation caused by changes in greenhouse gases and stratospheric aerosol concentrations. Also, these temperature projections are best done on a continental scale — not a regional scale, which is important in heat waves, droughts, etc.

The fact remains that climate models remain woefully inadequate in estimating the response of precipitation to perturbations in solar radiation at all scales. In other words, any predictions related to changes in rainfall are highly uncertain as dust is thrown into the atmosphere or into space to block sunlight.

Conversely, it would be reckless to conclude that SRM will not have unintended consequences in the form of drought and crop losses, or that it will lead to “positive” changes in national GDP, based on models that cannot reliably predict precipitation.

Geoengineering Governance

We need to keep in mind the fate of the global south, which may once again become an innocent bystander to a massive experiment in the global north—just as the global north continues to industrialize and trigger global warming, the consequences of which will bear the greatest impact on the global south.

Other climate mitigation strategies, such as the use of renewable energy, emission reduction schemes, carbon capture technologies and bioenergy, are not expected to have any dangerous unintended consequences. On the other hand, spraying aerosols on even a small area of ​​the stratosphere can have global consequences that we cannot currently fully quantify.

Many natural and social scientists have expressed serious concerns about the science and governance of SRM. Who will decide when, where and how much aerosols are deployed? Who will oversee unintended consequences? Who is responsible if one country conducts experiments that affect rainfall in other countries? Will the damage caused be compensated? Note that we are still grappling with the concept of “loss and damage” under the United Nations Framework Convention on Climate Change, the instrument for compensating countries for damages caused by climate change. Compensation for unexpected results of SRM will be more controversial.

The Oxford and Asilomar conferences presented guiding principles for climate geoengineering attempts. Some takeaways: Those involved must clearly and explicitly report on the science and technology of these approaches and their consequences—the good, the bad, and the ugly; the governance of deployment and monitoring, verification, and reporting should be democratic and inclusive; stakeholders must codify And agree up front on compensation mechanisms for any damages.

Finally, a major caveat with the aerosol loading method is the rebound effect once the spray ceases and the aerosol is flushed out of the atmosphere. Even when the temperature drops temporarily, we still need to reduce emissions. If we don’t, the cooling effect ends and the heating period begins.

But if industry and political leaders see cooling as a license to continue business as usual, we’re sure to create Frankenstein monsters.

Raghu Murtugudde is a Visiting Professor at the Indian Institute of Technology Bombay and Professor Emeritus at the University of Maryland.