Supporters say a sunshade would not eliminate the need to stop burning coal, oil and gas, the main drivers of climate change. Even if greenhouse gas emissions from fossil fuels were immediately reduced to zero, there are already large amounts of carbon dioxide trapping heat in the atmosphere.
The Earth's average temperature is about to rise 1.5°C above the pre-industrial average. Scientists say this is the point beyond which the chances of severe storms, droughts, heatwaves and wildfires will increase dramatically and humans and other species will struggle to survive. The planet has already warmed by 1.2 degrees Celsius.
Supporters of the idea say the canopy would help stabilize the climate, while other strategies to mitigate the effects of climate change are being pursued.
An undated image provided by the Technion-Israel Institute of Technology and the Asher Institute for Space Research shows a rendering of a giant sail that scientists want to send into space to block solar radiation. credit: ASRI via The New York Times
“I'm not saying this will be the solution, but I think everyone should work to find all possible solutions,” Chabuddy said.
It was in 1989 when James Early of Lawrence Livermore National Laboratory proposed creating a “space sun shield” that would be placed near a fixed point between Earth and the Sun called Lagrange Point One, or L1, about 1.5 million kilometers away, four times the distance from Earth. And the sun. Average distance between Earth and Moon. There, gravitational forces from the Earth and the Sun cancel each other out.
In 2006, Roger Angell, an astronomer at the University of Arizona, presented his proposal for a deflected sun shield at the National Academy of Sciences and later received a grant from the NASA Advanced Concepts Institute to continue his research. He proposed launching trillions of ultra-light spacecraft at L1, using a transparent film and guidance technology that would prevent the hardware from drifting out of orbit.
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“It's like you just turned a knob on the sun, and you're not messing with the atmosphere,” Angel said.
The umbrella idea has its critics, including Suzanne Bohr, a doctoral student focusing on modeling solar radiation modulation at the European Center for Advanced Research and Training in Scientific Computing in France. She said the parachute would be too expensive to implement in time, given the speed of global warming. In addition, a solar storm or collision with stray space rocks could damage the shield, leading to a sudden and rapid rise in temperatures with disastrous consequences.
She said time and money would be better spent working to reduce greenhouse gas emissions and remove carbon dioxide from the atmosphere, with a small portion of research devoted to solar geoengineering ideas that are “most feasible and cost-effective.”
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But Umbrella proponents say that reducing greenhouse gas emissions at this point will not be enough to calm climate chaos, that removing carbon dioxide has proven too difficult to achieve, and that all potential solutions must be explored.
A fully functional solar canopy must be flexible and reversible, Chabuddy said. In his proposed design, he said 99% of its weight would come from the asteroid, which would help offset the cost. He added that its price would likely reach trillions of dollars, which is much less than what is spent on military weapons.
“Saving the Earth and giving up 10 percent of your weapons to destroy things is actually a pretty good deal in my book,” he said.
He gave Tesla as an example of an idea that once seemed very ambitious, but within 20 years of its founding it had become the world's largest electric car manufacturer.
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One reason sunshades haven't gained as much attention is that climate researchers have, quite naturally, focused on what's happening inside Earth's atmosphere rather than in space, said Morgan Goodwin, executive director of the Planetary Sunshade Foundation, a nonprofit.
But Goodwin said falling space launch costs and investments in the space industrial economy have expanded the possibilities. The Foundation proposes to use raw materials from space and launch solar shadow ships to L1 from the Moon, which would be much less expensive than launching from Earth.
“We believe that as the idea of solar canopies becomes increasingly understood by climate workers, they will be a very visible part of the discussion,” said Goodwin, who is also senior director of the Sierra Club's Los Angeles chapter.
The Technion model involves attaching lightweight solar sails to a small satellite that is transmitted to L1. Their prototype would move back and forth between L1 and another balance point, tilting the sail between pointing at the sun and being perpendicular to it, moving like a slat on a Venetian blind. This would help keep the satellite stable and eliminate the need for a propulsion system, Rosen said.
Rosen said the team is still in the pre-design phase but could launch a prototype within three years after securing funds. He estimated that the full-sized version would cost trillions of dollars—a cost that “the world has to pick up, not one country,” he said—but would lower the Earth's temperature by 1.5 degrees within two years.
“We at the Technion are not going to save the planet,” Rosen said. “But we will show that it can be done.”
This article originally appeared on New York times.
