If something is impossible, there is a possibility of progress.
“There are many cases in which science fiction becomes science,” says Carlo Ratti, a researcher at the Massachusetts Institute of Technology (MIT). “Arthur C. Clarke, known for his science fiction books, proposed a network of geostationary satellites in the mid-20th century. This idea is at the center of current communications on Earth,” he adds.
At a time when the planet is at the point of greatest warming since records are made and this is a runaway race towards overheating, physicists and astronomers are proposing solutions that seem to come from speculations about the impossible.
Faced with the realization that climate change is getting worse, the initiative is taking shape, comparable to opening an umbrella on a sunny day, to create a large protective shield that floats in outer space to protect the Earth from a small but crucial amount of radiation, enough to contain global warming. According to scientific calculations, just blocking 1.8% of the sun's rays would be enough to cool the planet by 1.5º Celsius and bring it within manageable climatic limits.
The umbrella does not eliminate the need to curb the use of fossil fuels. Experts emphasize that the goal must continue to be zero emissions, but they add that, although that situation will be reached today, the existing accumulation would maintain warming for several decades. So proposals on the margins are beginning to gain strength with a notable increase in projects based on geoengineering or climate engineering to modify the Earth's climate on a large scale. “When I published my paper last summer, one of my colleagues told me it was the point where science fiction met reality,” says István Szapudi, an astronomer at the University of Hawaii.
This meeting is due to the lower costs of sending weight to space in the next ten years. “It doesn't mean it's easy. It needs a lot of effort, but it is technologically, scientifically and economically feasible,” he notes when considering his plan to attach a large solar shield to reused asteroids.
A fully operational umbrella – it remains to be determined whether it would be one large one or several small ones – would have to be resistant and reversible. 99% of the energy to move the weight would come from asteroids or the Moon. “The concept is simple. Due to the greenhouse effect, the amount of fixed radiation that reaches the Earth is too much and maintains a large amount inside. If part of the sun is covered, less radiation arrives and the temperature drops,” he explains.
In Israel, a group of scientists led by physics professor Yoram Rozen announced that they have created a prototype of an umbrella. Various sources emphasize that the starting point is in 1989. James Early, from the Lawrence Livermore National Laboratory, suggested the creation of a solar shield, positioned at a fixed point between the Earth and the Sun called Lagrange 1 or L1, at about 1.5 million kilometers from Earth, four times the distance between the planet and the Moon. At that point, the gravitational forces between the Earth and the Sun cancel each other out.
Roger Angel of the University of Arizona presented his proposal for reflective sunscreen to the United States National Academy of Sciences in 2006 and later received funding from NASA to continue his research. The basis of it was to release millions of space devices that would carry a transparent film. This would be the knob of a blind to block the sun without causing alterations in the atmosphere. Building on this work by Angel, a team at MIT is testing so-called “space bubbles,” described as the most efficient thin film structures for deflecting radiation. “This hasn't been tried before, but what should we do if things get out of control? This is the thought that leads us to explore new solutions,” emphasizes Ratti.
Critics counter that this deployment has a disproportionate economic cost. “The patient is in an emergency and needs different treatments. The solution is to cut carbon emissions but the sunshade is necessary to ensure that the patient lives long enough,” responds Morgan Woodwin, executive director of the Planetary Sunshade Foundation, a non-profit organization that has also made a proposal for a sun shield. “No one seems to want to talk – he insists – that, in a couple of decades, the impact of climate change will be very costly.”
