A new study published in PLOS Climate suggests using moon dust as a solar shield to keep Earth cool. Could this be a solution to climate change?
Scientists on Wednesday proposed regular transport of lunar dust to the point of gravity between the Earth and the Sun to overcome the damage of global warming.
The idea of filtering solar radiation to keep the earth from overheating has been around for decades, from giant space-based screens to creating reflective white clouds.
Climate concerns
But the continued failure to reduce planet-warming greenhouse gas emissions has pushed long-imagined geoengineering schemes to center stage in climate policy, investment and research.
A reduction of one to two percent of the Sun’s rays is all it takes to lower the Earth’s surface by a degree or two Celsius — about the amount it has warmed over the past century.
Stratospheric aerosols
The solar radiation technique with the most appeal to date is the injection of 24/7 billion shiny sulfur particles into the upper atmosphere.
So-called stratospheric aerosol injection would be cheap, and scientists know it works because major volcanic eruptions basically do the same thing. When Mount Pinatubo in the Philippines blew its summit in 1991, temperatures in the northern hemisphere dropped by 0.5C for almost a year.
But there are serious side effects, including disruption of rainfall patterns that millions of people depend on to grow food.
Lunar dust is a solar shield
However, a new study in the peer-reviewed journal PLOS Climate explores the possibility of using moon dust as a solar shield.[1]
A team of astronomers is applying methods used to track the formation of planets around distant stars – a messy process that causes huge amounts of space dust – to Earth’s moon.
Computer simulations show that placing lunar dust in the gravitational sweet spot between Earth and the Sun “blocks a lot of sunlight with very little mass,” said lead author Ben Bromley, a physics professor at the University of Utah.
‘Balancing the marbles’
The scientists tested several scenarios involving different properties and numbers of particles in different orbits, looking for the most abundant scenario.
A dusty moon works best. The amount required, he said, would require the equivalent of a major mining operation on Earth.
The authors emphasized that their study was designed to quantify potential impact, not logistical feasibility.
“We are not experts in climate change or rocket science,” said co-author Benjamin Bromley, a professor at the Harvard-Smithsonian Center for Astrophysics.
“We’re just exploring different types of dust in different orbits to see how effective this approach is,” he said. “We don’t want to miss a game changer because of a critical issue.”
Lunar dust research praised
Experts who were not involved in the study praised the methodology, but doubted its feasibility.
“Putting lunar dust at the midpoint of gravity between the Earth and the Sun, it can really reflect the heat,” said University of Edinburgh professor Stuart Haszeldine.[2]
“But it’s like trying to balance marbles in a football – within a week most of the dust has moved out of stable orbit.”
For Joanna Haigh, emeritus professor of atmosphere at Imperial College London, the study was a distraction.
The main problem, he said, “is the suggestion that the implementation of the scheme will solve the climate crisis, but only gives the polluters an excuse not to act.”[3]
Marlowe Hood © Agence France-Presse
Source:
[1] Dust is a solar shield, Benjamin C. Bromley, Sameer H. Khan, Scott J. Kenyon; February 8, 2023
[2] [3] Experts react to learning how dust is burned off the Moon to shield it from sunlight; Science Media Center, February 8, 2023