redOrbit: Thick smog clouds that loom over Asia threaten the livelihood of crops and contain particles that actually reflect the sun’s rays away from the earth, the United Nations reported on Thursday. “One of the impacts of this atmospheric brown cloud has been to mask the true nature of global warming on our planet,” United Nations Environment Program (UNEP) head Achim Steiner said at the launch in Beijing of a new report on the phenomenon. Caused by the burning of fossil fuels, wood …