Brightening Earth\u2019s clouds so that they reflect more sunlight just might cool the planet \u2014 that is if we can figure out how to do it without causing any unintended harm. To test the theory out, a group of over 30 leading scientists have written up a research road map that was published in the journal Science Advances<\/em> yesterday. <\/p>\n<\/div>\n The paper<\/a> focuses on how to approach attempts to artificially shade Earth\u2019s surface with marine clouds by spraying saltwater into the air from ships, a strategy called marine cloud brightening (MCB). They\u2019ll need to be really careful with any future experiments, which would fall into the controversial category of solar geoengineering. The idea is to counteract some of the effects of climate change by finding ways to reflect solar radiation. <\/p>\n<\/div>\n Researchers still don\u2019t understand how fruitful those efforts would be, nor whether they might inadvertently create new problems by messing with the planet in this way. But with climate change whipping up worsening disasters<\/a> and countries falling behind<\/a> on goals to reduce planet-heating pollution, some scientists see solar geoengineering as a possible contingency plan. <\/p>\n<\/div>\n \u201cWe need to consider non-ideal backup plans just to buy us enough time.\u201d<\/p>\n<\/div>\n<\/div>\n \u201cWe need to consider non-ideal backup plans just to buy us enough time,\u201d Lynn Russell, co-author of the paper and a climate scientist at the Scripps Institution of Oceanography at the University of California San Diego, said in a press release<\/a>. <\/p>\n<\/div>\n Geoengineering \u2014 deploying new technologies to manipulate the environment in a way that might lower global temperatures \u2014 does nothing to stop the greenhouse gas emissions causing climate change, she added. It could have the potential to slow down worsening climate disasters while policymakers work to reduce emissions. But first, it\u2019s important to know what the possible risks and benefits are. <\/p>\n<\/div>\n There have already been tussles over what, if any, role solar geoengineering should play as a climate solution and how to regulate it. So far, the drama has mostly surrounded a different strategy called stratospheric aerosol injection<\/a> (SAI), which involves catapulting particles up into Earth\u2019s stratosphere to reflect sunlight back into space. <\/p>\n<\/div>\n One startup caused a global uproar<\/a> in 2022 when it forged ahead with its own makeshift SAI experiments despite a\u00a0de facto global moratorium<\/a>\u00a0on large-scale geoengineering. You can watch the co-founders on YouTube\u00a0grilling fungicide<\/a> in a parking lot to create sulfur dioxide gas\u00a0they then launch aboard a weather balloon<\/a>. Even groups optimistic about solar geoengineering balked<\/a> at the experiments, saying it undermined more serious research into how to mimic the way volcanoes have\u00a0temporarily cooled<\/a> the planet when\u00a0spewing\u00a0sulfur dioxide<\/a> during eruptions. <\/p>\n<\/div>\n Since then, there\u2019s been a push within academia and international institutions including the United Nations<\/a> and European Union<\/a> to craft stronger guidelines for solar geoengineering. Some environmental advocates oppose solar geoengineering<\/a> altogether, saying the uncertainties are too great and that climate solutions need to focus on preventing greenhouse gas emissions causing climate change.<\/p>\n<\/div>\n Scientists are even more unsure of the effects of marine cloud brightening than they are of stratospheric aerosol injection. So it\u2019s no surprise that the authors of the new MCB paper want to proceed with caution. The group of 31 scientists from around the world convened in 2022 to assess where the current scientific understanding of marine cloud brightening stands and what knowledge gaps need to be filled. The paper they published this week summarizes their findings and proposes a plan for advancing MCB research.<\/p>\n<\/div>\n Marine cloud brightening mimics the effects of volcanic eruptions. But unlike SAI, it entails sending reflective particles into low-lying clouds instead of higher up into the stratosphere. Sulfur in pollution from ship stacks has also been shown to have a similar reflective effect, although recent research<\/a> suggests this might have been overestimated in the past. <\/p>\n<\/div>\n