Radical “geoengineering” projects including simulated volcanoes and man-made sun blocks could prove handy weapons in the fight against climate change, scientists are claiming. “It would be 100 times cheaper to shield the Earth from sunlight with a man-made ‘sun block’ than to cut emissions of greenhouse gases. This is one of the reasons why the world needs an international project to investigate ways of safely manipulating the global climate in addition to cutting greenhouse gases, scientists have said. Simulating a volcanic eruption by putting man-made aerosol particles into the atmosphere to reflect the Sun's heat would rapidly lower global temperatures and could provide a vital respite from global warming until cuts in carbon dioxide emissions begin to have the desired effect, they added. It is important to start tests in ‘geoengineering’ now rather than leave it until a full-blown emergency, according to three environmental scientists who argue that governments should establish a multimillion-pound fund to pay for research into solar-radiation management – techniques for shielding the Earth against sunlight.”