AFP – In a sign of out-of-the-box thinking or desperation, scientists on Wednesday proposed regular transport of moon dust to a gravitational point between Earth and the sun to reduce the ravages of global warming.
Ideas for filtering solar radiation to keep Earth from overheating have been floating around for decades, from giant space-based screens to churning out reflective white clouds.
But the persistent failure to reduce planet-warming greenhouse gas emissions has pushed once-hypothetical geoengineering schemes to center stage in climate policy, investment and research.
Blocking just one to two percent of the sun’s rays could cool Earth’s surface by a degree or two—roughly as much as it has warmed over the past century.
The solar irradiation technique with the most traction by far is the 24/7 injection of billions of luminous sulfur particles into the upper atmosphere.
So-called stratospheric aerosol injection would be cheap, and scientists know it works because major volcanic eruptions do basically the same thing. When Mount Pinatubo in the Philippines erupted its top in 1991, it lowered the temperature in the Northern Hemisphere by about 0.5C for about a year.
But it also has serious potential side effects, including disruption of the rain patterns on which millions of people depend for growing food.
However, a new study in the peer-reviewed journal PLOS Climate explores the possibility of using Moon dust as a solar shield.
A team of astronomers applied methods used to track planet formation around distant stars – a messy process that carries vast amounts of space dust to Earth’s moon.
Computer simulations showed that lunar dust blocked a very small amount of sunlight, “putting into a gravitational sweet spot between Earth and the Sun,” said lead author Ben Bromley, professor of physics at the University of Utah.
The scientists tested several scenarios involving different particle properties and quantities in different orbits to determine which would cast the most shadows.
Moon dust worked best. The quantity required, he said, would require the equivalent of a large mining operation.
The authors stressed that their study was designed to calculate potential impact, not logistical feasibility.
“We are not experts in climate change or rocket science,” said study co-author Benjamin Bromley, a professor at the Harvard-Smithsonian Center for Astrophysics.
“We were looking for different types of dust in different orbits to see how effective this approach could be,” he said. “We don’t want to miss a game changer for such a serious problem.”
Experts who were not involved in the study praised its methodology but doubted whether it would actually work.
“Moon dust at the gravitational midpoint between Earth and the Sun may actually reflect heat,” said Professor Stuart Hazeldine, from the University of Edinburgh. “But it’s like trying to balance marbles on a football—within a week most of the dust is out of stable orbit.”
For Joanna Haigh, an emeritus professor of atmospherics at Imperial College London, the study is a distraction.
The main problem, she said, is “the suggestion that implementation of such plans will solve the climate crisis, while it gives polluters an excuse not to act.”
