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| Continuously launching a stream of dust from the moon could help to combat climate change: Paola Iamunno |
Launching a million tonnes of moon dust around Earth could dim sunlight across
our planet by 1.8 per cent. This would reduce the global temperature, but
whether it would be worth the resources, and the risks involved in such a
strategy, are unclear.
Launching a dust cloud from the moon to block sunlight reaching Earth could
reduce global warming, but such a strategy may require more than a decade’s
worth of research before it can be implemented. The risks involved with such
an approach in terms of how it could affect agriculture, ecosystems and
water quality in different parts of the world are also unclear.
Placing more than 100 million tonnes of dust between Earth and the sun to
partially block light from reaching our planet has previously been explored
as a way to combat climate change. Such dust particles would shade Earth by
absorbing light energy or scattering light particles, known as photons, away
from Earth.
To achieve this, the dust would need to be placed 1.5 million kilometres
from Earth, where the gravitational pull of the sun and our planet cancel
out. Here, objects stay at a fixed position known as the first Lagrange
point, or L1.
Different research groups have explored placing dust at L1, but energy from
photons and charged particles ejected from the sun, known as the solar wind,
can gradually nudge dust further away from its desired position, which would
need correcting.
Now, after running thousands of computer simulations, Benjamin Bromley at
the University of Utah and his colleagues have found that continuously
launching a stream of lunar dust directly from the moon’s north pole towards
L1 at a speed of 2.8 kilometres per second may be a better approach.
In this scenario, the simulations suggest that each propelled dust particle
spends about five days blocking Earth-bound sunlight, before dispersing
throughout the solar system.
Considering the gravitational pull of the sun, Earth and other planets, as
well as non-gravitational forces such as the solar wind, the simulations
found that maintaining a dust shield with a mass of 1 million tonnes near L1
for a year could dim sunlight across Earth by 1.8 per cent, equivalent to
completely blocking six days of sunlight.
If the approach were sustained indefinitely, or until other measures were
introduced to remove carbon dioxide from Earth’s atmosphere, this could
offset the rise in carbon dioxide levels that has occurred since the
industrial revolution, says Ben Kravitz at Indiana University, Bloomington.
“If this method works, it would certainly be effective at reducing global
temperature, but it’s hard to say whether it would be worth it relative to
the effort and resources used,” he says.
While the simulations didn’t model the use of any machinery to launch the
lunar dust towards L1, you could use a railgun, which propels things via
electromagnetic energy, says Bromley. “This would be perfect because it
could be fueled by a few square kilometres of solar panels placed near the
launch site,” he says.
However, shading the entire Earth will have unequal effects in different
regions, says Kravitz. “Temperature, precipitation, winds and many other
things will change [as a result of this strategy], and they will change
differently in different places,” he says. “Those changes will, of course,
translate into effects on agriculture, ecosystems and water quality.”
Before a strategy like this can be implemented, large-scale engineering
studies need to be carried out by multiple agencies in different countries
and with consideration by the United Nations, says Curtis Struck at Iowa
State University.
Another issue is that there would probably be inaccuracies in the launch and
scattering of the dust, which would have unknown effects. “Would there be
enhanced micrometeorite falls to Earth and damage to Earth-orbiting
satellites?” says Struck. “This and many other questions have not been
studied in the necessary detail.”
Furthermore, considering an approach like this shouldn’t replace our efforts
to decrease carbon emissions on Earth. “We have to keep reducing the
greenhouse gases within our own atmosphere, no matter what,” says Bromley.
“Our dust shield solution would simply buy us more time.”
Reference:
Bromley BC, Khan SH, Kenyon SJ (2023) Dust as a solar shield. PLOS Clim 2(2):
e0000133.
DOI: 10.1371/journal.pclm.0000133
|
| Continuously launching a stream of dust from the moon could help to combat climate change: Paola Iamunno |
Launching a million tonnes of moon dust around Earth could dim sunlight across
our planet by 1.8 per cent. This would reduce the global temperature, but
whether it would be worth the resources, and the risks involved in such a
strategy, are unclear.
Launching a dust cloud from the moon to block sunlight reaching Earth could
reduce global warming, but such a strategy may require more than a decade’s
worth of research before it can be implemented. The risks involved with such
an approach in terms of how it could affect agriculture, ecosystems and
water quality in different parts of the world are also unclear.
Placing more than 100 million tonnes of dust between Earth and the sun to
partially block light from reaching our planet has previously been explored
as a way to combat climate change. Such dust particles would shade Earth by
absorbing light energy or scattering light particles, known as photons, away
from Earth.
To achieve this, the dust would need to be placed 1.5 million kilometres
from Earth, where the gravitational pull of the sun and our planet cancel
out. Here, objects stay at a fixed position known as the first Lagrange
point, or L1.
Different research groups have explored placing dust at L1, but energy from
photons and charged particles ejected from the sun, known as the solar wind,
can gradually nudge dust further away from its desired position, which would
need correcting.
Now, after running thousands of computer simulations, Benjamin Bromley at
the University of Utah and his colleagues have found that continuously
launching a stream of lunar dust directly from the moon’s north pole towards
L1 at a speed of 2.8 kilometres per second may be a better approach.
In this scenario, the simulations suggest that each propelled dust particle
spends about five days blocking Earth-bound sunlight, before dispersing
throughout the solar system.
Considering the gravitational pull of the sun, Earth and other planets, as
well as non-gravitational forces such as the solar wind, the simulations
found that maintaining a dust shield with a mass of 1 million tonnes near L1
for a year could dim sunlight across Earth by 1.8 per cent, equivalent to
completely blocking six days of sunlight.
If the approach were sustained indefinitely, or until other measures were
introduced to remove carbon dioxide from Earth’s atmosphere, this could
offset the rise in carbon dioxide levels that has occurred since the
industrial revolution, says Ben Kravitz at Indiana University, Bloomington.
“If this method works, it would certainly be effective at reducing global
temperature, but it’s hard to say whether it would be worth it relative to
the effort and resources used,” he says.
While the simulations didn’t model the use of any machinery to launch the
lunar dust towards L1, you could use a railgun, which propels things via
electromagnetic energy, says Bromley. “This would be perfect because it
could be fueled by a few square kilometres of solar panels placed near the
launch site,” he says.
However, shading the entire Earth will have unequal effects in different
regions, says Kravitz. “Temperature, precipitation, winds and many other
things will change [as a result of this strategy], and they will change
differently in different places,” he says. “Those changes will, of course,
translate into effects on agriculture, ecosystems and water quality.”
Before a strategy like this can be implemented, large-scale engineering
studies need to be carried out by multiple agencies in different countries
and with consideration by the United Nations, says Curtis Struck at Iowa
State University.
Another issue is that there would probably be inaccuracies in the launch and
scattering of the dust, which would have unknown effects. “Would there be
enhanced micrometeorite falls to Earth and damage to Earth-orbiting
satellites?” says Struck. “This and many other questions have not been
studied in the necessary detail.”
Furthermore, considering an approach like this shouldn’t replace our efforts
to decrease carbon emissions on Earth. “We have to keep reducing the
greenhouse gases within our own atmosphere, no matter what,” says Bromley.
“Our dust shield solution would simply buy us more time.”
Reference:
Bromley BC, Khan SH, Kenyon SJ (2023) Dust as a solar shield. PLOS Clim 2(2):
e0000133.
DOI: 10.1371/journal.pclm.0000133
Tags:
Space & Astrophysics