Solar gEOENGINEERING is a heated topic. The core idea is to deliberately interfere with the environment in order to cool the climate, thus averting the worst consequences of the unintentional interference caused by rampant fossil-fuel combustion. Most of the potential methods involve reflecting sunlight back into space, thereby stopping that energy being trapped in the atmosphere as heat. Those in favour of researching them point to their potential to cheaply and substantially reduce global temperatures. Critics, meanwhile, highlight the risk of altering weather systems and disrupting atmospheric chemistry (with global and ungovernable consequences) while distracting countries from the hard but necessary work of cutting carbon emissions.