10 November 2017, Climate News Network: Geo-engineering can work – if the world wants it. Geo-engineering can stop the Earth warming, at least in theory, scientists say, but doubts persist over the possible risks. Climate scientists now know that geo-engineering – in principle at least – would halt global warming and keep the world at the temperatures it will reach by 2020. It is simple: inject millions of tons of sulphate aerosols into the stratosphere at carefully chosen locations, and keep on doing so for as long as humans continue to burn fossil fuels and release greenhouse gases into the atmosphere. The desired effect: global temperatures will be contained because the pollutants in the upper atmosphere will dim the sun’s light and counteract the greenhouse effect of all the carbon dioxide pumped from power stations, vehicle exhausts, factory chimneys and burning forests. It won’t be the perfect answer. The oceans will go on becoming more acidic, and the skies will become subtly darker. Rainfall patterns could be affected. Repairs to the ozone layer – an invisible shield against dangerous ultraviolet radiation – would be slowed.The volumes of sulphate aerosols that would need to be flown to stratospheric heights and released each year would continue to grow as humans went on burning ever more fossil fuels. The technical and energy demands of such an operation would be colossal. There could be serious geopolitical problems about the impacts and responsibility for such decisions. But, at least in principle, researchers now believe geo-engineering could be made to work. “For decision makers to accurately weigh the pros and cons of geo-engineering against those of human-caused climate change, they need more information,” said Ben Kravitz, of the Pacific Northwest National Laboratory, and one of a consortium which has published a succession of five studies in the Journal of Geophysical Research – Atmospheres. “Our goal is to better understand what geo-engineering can do – and what it cannot.” Read More here