With the Earth at its point hottest of history, and humans doing everything they can to stop their overheating, a small but growing number of astronomers and physicists are proposing a potential solution that could have stepped out of the pages of science fiction: the equivalent of a giant beach umbrella, floating in outer space.
The idea is to create a huge parasol and send it to a distant point between the Earth and the Sun to block a small amount but crucial amount of solar radiation, enough to counteract global warming.
Scientists have calculated that if you block something less than 2% of solar radiation, would be enough to cool the planet by 1.5 degrees Celsius, or 2.7 Fahrenheit, and keep Earth within about manageable climatic limits.
The idea has been on the sidelines of conversations about climate solutions for years.
But as the climate crisis worsens, interest in solar shields has been gaining momentum, and more and more researchers are proposing variants.
There is even a foundation dedicated to promoting solar shields.
Scientists are seeking $10 million to $20 million to build a smaller model to demonstrate the concept. Source Technion Israel Institute of Technology and Asher Space Research Institute.
A recent study led by the University of Utah explored the dispersion of dust in space, while a team from the Massachusetts Institute of Technology studies the creation of a shield made of “space bubbles“.
Last summer, Istvan Szapudi, astronomer at the University of Hawaii Institute of Astronomy, published a paper suggesting tying a large solar shield to a repurposed asteroid.
Now, scientists led by Yoram Rozen, professor of physics and director of the Asher Space Research Institute at the Technion-Israel Institute of Technology, say they are ready to build a shadow prototype that shows that the idea works.
According to Rozen, to block the necessary amount of solar radiation, the shadow would have to have a surface area of 2,589,988. square kilometers, approximately the size of Argentina.
A screen this big would weigh at least 2.5 million tonstoo much to launch into space.
Therefore, the project would have to include a series of smaller screens.
A representation of a giant candle. (Technion Israel Institute of Technology and Asher Space Research Institute via The New York Times)
They would not completely block sunlight, but would instead project a slightly diffuse shadow on Earth.
Rozen said his team was ready to design a prototype display 30 square meters and that it is seeking between 10 and 20 million dollars to finance the demonstration.
“We can show the world:
'Look, there's a solution that works, take it, scale it up to the size you need,'” he said.
The sail would tilt like the slat of a Venetian blind, sometimes pointing at the sun and other times perpendicular to it. Source Israel Technion Institute of Technology and Asher Space Research Institute.
Proponents 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 is already a excess carbon dioxide that traps heat.
The Earth's average temperature is about to rise 1.5 Celsius above the pre-industrial average.
That is the point at which the chances of extreme storms, droughts, heat waves and wildfires would increase significantly and humans and other species would have a harder time surviving, scientists say.
The planet has already warmed by 1.2 degrees Celsius.
A parasol would help stabilize the climate, supporters of the idea say, while pursuing other strategies climate mitigation.
“I'm not saying this is going to be the solution, but I think everyone has to work to find all the possible solutions,” said Szapudi, the astronomer who proposed tying a sunshade to an asteroid.
It was in 1989 when James Earlyfrom the Lawrence Livermore National Laboratory, suggested a “space sun shield” located near a fixed point between the Earth and the Sun called Point One by Lagrangeor L1, about 932,000 kilometers away, four times the average distance between the Earth and the Moon.
There, the gravitational forces of the Earth and the Sun are canceled mutually.
In 2006, Roger Angelan astronomer at the University of Arizona, presented his deflecting solar shield proposal at the National Academy of Sciences and subsequently obtained a grant from NASA's Institute for Advanced Concepts to continue his research.
He suggested launching billions of very light spacecraft at L1, using transparent film and guidance technology that would prevent the devices from deorbiting.
“It's like you lower a controller into the sun,” Angel said, “and you don't mess with the atmosphere.”
The idea of the sunshade has its detractors, among them Susanne Baur, a doctoral student in modeling the modification of solar radiation at the European Center for Research and Advanced Training in Scientific Computing in France.
According to Baur, a parasol would be astronomically expensive and could not be implemented on time, given the speed of global warming.
Additionally, a solar storm or a collision with stray space rocks could damage the shield and cause sudden, rapid heating with disastrous consequences, according to Baur.
In his opinion, it would be better to invest time and money in reduce emissions of greenhouse gases and removing carbon dioxide from the atmosphere, dedicating a small part of the research to ideas of solar geoengineering “more viable and profitable.”
But proponents of sunshades say that at this point, reducing greenhouse gas emissions will not be enough to quell climate chaos, that removing carbon dioxide has proven extremely difficult to achieve, and that all avenues must be explored. the possible solutions.
According to Szapudi, a fully operational parasol would have to be resistant and reversible.
In their design proposal, 99% of its weight would come from the asteroid, which would help offset the cost.
Even so, its price would probably rise to trillions of dollars, an amount much less than what is spent on military weapons, according to Szapudi.
“In my opinion, saving the Earth and giving up 10% of weapons to destroy things is good business,” says Szapudi.
Heart a Tesla as an example of an idea that at the time seemed tremendously ambitious, but 20 years after its founding it became the world's first manufacturer of electric vehicles.
Morgan Goodwin, executive director of the Planetary Sunshade Foundationa nonprofit organization, says one reason sunshades haven't gained as much traction is that climate researchers have naturally focused on what's happening inside Earth's atmosphere and not on space.
But the cheaper launches of space and investments in an industrial space economy have expanded the possibilities, Goodwin says.
The foundation suggests using raw materials from space and launch sunshade ships to L1 from the Moon, which would cost much less than launching from Earth.
“We think that as climate people better understand the idea of umbrellas, it will become a pretty obvious part of the debate,” said Goodwin, who is also director of the Los Angeles chapter of the Sierra Club.
The Technion model consists of fix light solar sails to a small satellite sent to L1.
His prototype would move back and forth between L1 and another balance point, with the sail tilted 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 systemRozen explained.
Rozen stated that the team is still in the pre-design phase, but could launch a prototype within three years after obtaining the necessary funds.
He estimated that a full-size version would cost billions (a bill “that would have to be paid the world, not just one country“he said) but it would reduce the Earth's temperature by 1.5 Celsius in two years.
“At the Technion we are not going to save the planet,” Rozen said.
“But we are going to show that it can be done.”
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