February 8, 2023

expert reaction to study on dust fired from the Moon to shield the sun’s rays

A study published in PLOS Climate looks at the use of dust as a solar shield.

Prof Joanna Haigh FRS, Emeritus Professor of Atmospheric Physics at Imperial College London, said:

“The calculations are carefully considered and the results with regard to the Earth’s energy balance appear robust. In terms of mitigating global warming, however, there is a fundamental problem with the concept behind this type of global geoengineering. An Earth with less solar irradiance and greater infrared greenhouse effect is not the same as one in which both these factors are unchanged. The geographical distribution of the net energy input means that global atmospheric (and oceanic) circulations, weather patterns and clouds are different. Perhaps the main problem, however, is the suggestion that implementation of such schemes will solve the climate crisis whereas it just gives the polluters an excuse not to act.”

Prof Stuart Haszeldine, University of Edinburgh, said:

“The authors are correct that managing earth’s climate by decreasing CO2 emissions is not working. Most years are getting hotter. So it’s very efficient to plan for reflecting just 1-2% of solar heating. And there are multiple proposals to do that, both practically and exotically.

“Placing moon dust at the gravity mid-point between earth and sun, can indeed reflect heat- with the right particle shape, at the right size, and in exactly the right place. But this is like trying to balance marbles on a football, within a week most dust has spun out of stable orbit. Which is why there is no natural dust accumulation at this astronomical point. There are easier methods to decrease heating of the earth, and humans should now be enacting those to repair climate.”

‘Dust as a solar shield’ by Benjamin C. Bromley et al. was published in PLOS Climate at 7pm UK TIME on Wednesday 8 February 2023.

https://doi.org/10.1371/journal.pclm.0000133

Declared interests

Prof Joanna Haigh: “I have no invested interests.”

Prof Stuart Haszeldine has no commercial interests in this topic, and receives UKRI funds to research on decreasing carbon emissions, not climate repair