Debates about its efficacy abound, with the United States, Europe and several environmental groups speaking out about the opportunities and risks. Research has been conducted into other potentially less dangerous SRM technologies, including marine cloud brightening, which involves the spraying of seawater from ships to make clouds more reflective. One group of 60 scientists launched a global initiative last year aimed at persuading governments to ban outdoor solar geoengineering experiments. "Once you've committed to it, you've got to keep doing it," said Laura Wilcox, a climate expert at Britain's University of Exeter. "If you stop, then you're going to see all of that warming that you've missed, essentially on climate timescales overnight.

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Persons: Luke Iseman, SO2, Benjamin Sovacool, Andrea Hinwood, you've, Laura Wilcox, David Stanway, Jake Spring, Pravin Organizations: REUTERS, U.S . National Academy of Sciences, Company, Reuters, Harvard University, Swedish Space Corporation, Research, Boston University, SRM, United Nations Environment Program, Britain's University of Exeter, Pravin Char, Thomson Locations: Baja California, Mexico, Handout, United States, Europe, China, England, Africa, Asia