GEOENGINEERINGCan Space Dust Slow Global Warming?

Published 23 February 2023

Scientists believe dust launched from the moon could reduce solar radiation enough to lessen the impact of climate change.

Intercepting a fraction of the sun’s energy before it reaches Earth may be enough to reverse the planet’s rising temperatures, say scientists who are looking at dust as a potential shield.

For decades, scientists have considered using screens or other objects to block just enough of the sun’s radiation — between 1 or 2 percent — to mitigate the effects of global warming. In this new study, led by the Center for Astrophysics | Harvard & Smithsonian and the University of Utah, scientists are exploring the potential use of dust to shade the Earth.

The paper, published Wednesday in the journal PLOS Climate, notes launching dust between Earth and the sun to a way station at the “Lagrange Point” would be the most effective, however, it would also be cost prohibitive and labor intensive. As an alternative, the team proposes moondust, arguing that lunar dust launched from the moon could be a low-cost and effective shield.

“It is amazing to contemplate how moondust — which took over 4 billion years to generate — might help slow the rise in the Earth’s temperature, a problem that took us less than 300 years to produce,” says study co-author Scott Kenyon of the Center for Astrophysics.

The team of astronomers applied a technique used to study planet formation around distant stars — their usual research focus — to the lunar dust concept. Planet formation is a messy process that kicks up astronomical dust, which forms rings around host stars. These rings intercept light from the central star and re-radiate it in a way that can be detected.

“That was the seed of the idea; if we took a small amount of material and put it on a special orbit between the Earth and the sun and broke it up, we could block out a lot of sunlight with a little amount of mass,” says Ben Bromley, professor of physics and astronomy at the University of Utah and lead author for the study.

Casting a Shadow
According to the team, a sunshield’s overall effectiveness would depend on its ability to sustain an orbit that casts a shadow on Earth. Sameer Khan, Utah undergraduate student and study co-author, led the initial exploration into which orbits could hold dust in position long enough to provide adequate shading.