To help combat the effects of global warming, scientists are working on an innovative idea. To protect our planet from the Sun, we could use a kind of space ‘umbrella’ to slow down climate change.
Idea of umbrella
“At Hawaii, many people use an umbrella to block the sunlight while walking during the day” said István Szapudi, an astronomer at the Institute for Astronomy at the University of Hawaii. “I was thinking, could we do the same for the Earth and thus mitigate the impending catastrophe of climate change ?”.
The reason carbon dioxide and other greenhouse gases contribute to global warming is that they trap solar radiation around our planet that should be released into space. This phenomenon gradually leads to rising temperatures. But it’s the Sun that generates the heat. Hence the idea of building an artificial shade over the Earth.
Szapudi elaborated in a study (ref.) on an “umbrella” positioned at the L1 Lagrange point between the Sun and the Earth. It would reach solar observation probes such as the Solar and Heliospheric Observatory (SOHO) and the Advanced Composition Explorer (ACE). According to calculations, a sufficiently large solar shield could effectively block about 1.7% of the solar radiation from L1. A percentage enough to prevent a catastrophic increase in Earth‘s temperatures.
However, any kind of useful space umbrella against climate change is bound to face a tough engineering challenge. At the L1 point, it would be subject to both the gravity of the Sun and the Earth while experiencing a constant solar radiation. It would, therefore, need to be a massive object weighing millions of tons and made with a sturdy material to remain intact. At the moment, we don’t have a practical way to launch such a large weight into orbit.
To work around this problem, Szapudi has proposed that much of the material itself can come from space, from a captured asteroid or even lunar dust. This material could theoretically serve as a counterweight, attached to a much smaller shield of about 35,000 tons. But even in this case, a shield that small would be too heavy to be lifted by a rocket. It’s likely that with advancements in materials, we could tackle this endeavor in several decades.