Cooling earth with moon dust – a clever climate solution or making Frankenstein’s monster? Premium

There is some reason to believe that the summerless year that followed the eruption of Mt. Tambora i

There is some reason to believe that the summerless year that followed the eruption of Mt. Tambora in 1816 inspired the horror novels Frankenstein and The Vampyre. Some have also argued that Edvard Munch’s famous 1893 painting ‘The Scream’ was also inspired, in part, by the sight of a sky after a volcanic eruption.

A sufficiently powerful volcanic eruption can spew sulphates 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, among others. The U.S. government is currently officially supporting research on solar radiation management (SRM).

In a controversy late last year, a private venture called Make Sunsets released tiny amounts of sulphur dioxide into the stratosphere using balloons in an effort to sell ‘solar-dimming’ as a way to offset carbon emissions. To many researchers the event was a major red flag signalling the colonisation of common goods like the atmosphere by private players.

The latest media buzz on this front comes from a paper recently published in the journal PLoS Climate on February 8. Researchers from the U.S. have proposed that billions of tonnes of dust can be launched from the moon to a Lagrange point – a point in space where the earth’s and the Sun’s gravitational fields cancel each other out. The feat is obviously beset by severe technical and economic challenges, yet there is interest in it.

The science of the consequences of volcanic eruptions is well-established. Aerosols in the stratosphere, especially radiation-scattering ones such as sulphates, do have a cooling effect. This is what led to the ‘year without summer’ – but it would be unwise to forget the other consequences of the same eruption. The cool summer led to widespread drought across the planet, sent crop yields plummeting, leading to disease and starvation. Many climate models have confirmed that dimming the amount of incoming sunlight with stratospheric aerosols will have similar outcomes.

Some recent studies have argued that the resulting drought won’t be as harmful and that the GDPs of most countries will be positively affected by this approach to SRM. But we should remember that even state-of-the-art climate models are skilled only at guessing the temperature response to changes in solar radiation caused by changes in the concentrations of greenhouse gases and stratospheric aerosols. In addition, these temperature projections are best at the continental scale – not at the regional scale, which matters when it comes to heatwaves, drought, and such.

The fact remains that climate models are still woefully inadequate at estimating the precipitation response to solar radiation perturbations at all scales. In other words, any projections related to changes in rainfall, as a result of throwing up dust into the atmosphere or in space to block sunlight, will be highly uncertain.