Why a giant space sunshade is being pitched as a serious solution to climate change

Scientists at an Israeli technology institute say they’re ready to build a prototype sunshade to launch into space to reduce the amount of solar radiation entering Earth’s atmosphere. The idea was previously only popular on the fringes of the scientific community, but is now being treated with cautious seriousness. While a full-sized sunshade would have to be the size of Kazakhstan, the prototype would be a 100 square-metre proof-of-concept. The lead professor on the case said: “We can show the world, ‘Look, there is a working solution; take it — increase it to the necessary size.’” A prototype would cost $10-20 million, while a complete space shade could be one of the most expensive things ever built (the current record-holder is the International Space Station). It would be positioned 1.5 million km from earth at Lagrange Point 1, held perpetually between the sun and earth by gravitational equilibrium. Some climate experts say the money would be better spent at home, deterring greenhouse gas production.