Mercury: Scientists are so concerned about global warming that they're now calling for tests to find ways to cool the planet -- the first step toward exploration of a highly controversial field that sounds like science fiction.
"Geoengineering," which is aimed at changing the climate by blocking the sun's powerful rays, may be necessary if society can't agree on how to stop carbon emissions that are heating up Earth, a panel of experts said Saturday in San Jose at the meeting of the American Association...