Bubble shield in space to prevent climate collapse
by Kai Stubel
6/22/2020, 5:37 pm
With global warming increasing, people are desperately searching for solutions to the climate problem. The researchers now propose dimming some of the sunlight with a giant carpet of bubbles in space. In theory, it sounds tempting – but there are still many obstacles.
Climate change threatens to elude humanity. Heat waves are becoming more common. The researchers are already warning that the 1.5-degree warming threshold may fall in the coming years. This was once considered the upper limit of the permanent warming target agreed upon by the world’s nations in the Paris climate agreement in 2015. At the same time, global collective carbon dioxide emissions continue. So what do you do?
One solution could be solar geoengineering. Basic Idea: Part of the sunlight is simply reflected away from the Earth. Because the less sunlight reaches the Earth’s atmosphere, the less its temperature will rise.
For example, there is the idea of distributing aerosols in the stratosphere that reflect sunlight. This actually works – when the Pinatubo volcano in the Philippines erupted in 1991, it was observed that the Earth cooled by about 0.3 to 0.5 degrees due to sulfur dioxide blasting into the higher layers of the air. But there are several concerns about mimicking something like this technically, for example with aircraft fleets. Because it is difficult to get rid of an aerosol if the whole thing does not have the desired or even negative effects on the climate.
Another approach is giant space shields that dim sunlight slightly. According to calculations, a 1.8 percent decrease in solar radiation could reverse global warming. Researchers at the famous Massachusetts Institute of Technology (MIT) in the USA are now introducing a new concept of this kind. Her sun shield consists of a giant “raft” of frozen bubbles. It is said to be roughly the size of Brazil and is positioned 2.5 million kilometers from Earth in front of the Sun – near the so-called Lagrangian Point, where the gravitational forces of both celestial bodies cancel each other out.
Thin wafer cases
The idea of making giant Earth sunglasses is not new. There have been proposals in the past to launch large flakes or swarms of small spacecraft with sun shields. But the technical challenges are enormous. The biggest problem is getting huge amounts of material into space. The solution offered by the MIT researchers: Bubbles must have thin films in order to save material. According to calculations, it should be only 400-600 nanometers thick – a sheet of paper will be about 200 times thicker.
The first experiments actually succeeded in inflating the thin bubble at a pressure of 0.0028 of the atmosphere and keeping it at about minus 50 degrees — conditions roughly close to those in space, the researchers wrote in a statement. Potential substances are ionic liquids – salts that are already liquid at room temperature. “The main advantage of the bubble screen is the ability to assemble on site, using space-based manufacturing techniques,” the authors said. Disassembly is also easy – bubbles can simply be popped when they are not needed. “This would make solar geoengineering completely reversible and significantly reduce space debris.”
But the authors acknowledge that a lot of research is still needed to make all of this a reality. For example, with the aim of transporting raw materials or assembling a canopy. Researchers are already thinking about future space concepts, such as magnetic guns (“electromagnetic guns”) to launch the necessary materials into space – however, such a thing has so far only existed on paper. In addition, the fragile structure will probably have to be constantly renewed. And the solar wind threatens to push it away over time, which must also be resolved.
Lots of unresolved issues
There are other challenges: it is not entirely clear, for example, how reduced solar radiation will affect Earth’s weather. Scientists and ecologists warned in an open letter earlier this year that the regional impacts of solar geoengineering could be devastating. Thus, artificially weakening the radiative power of the Sun is likely to interrupt the monsoon rains in South Asia and West Africa. It could wipe out the rain-fed agriculture there that feeds hundreds of millions of people.
Ultimately, the procedure may do more harm than good. And a supposedly simple technical solution to climate change could also reduce the urgent need to reduce carbon dioxide—in other words, humanity is likely to continue as before. However, the authors stress that the canopy should at best support efforts to reduce carbon dioxide.
Plus, the whole thing so far has been just a working hypothesis, according to an MIT statement. However, if all technical obstacles are overcome, the bubble sun shield could be built before the turn of the century, before the worst effects of climate change hit. According to old calculations, the costs will be about 0.5% of global GDP – over 50 years.