Ottawa Citizen: China’s greenhouse gas emissions have been grossly underestimated, according to a new study released on the eve of a U.S.-led conference in France this week involving major emitters seeking ways to deal with climate change. The University of California study, citing previously unavailable evidence, said China probably passed the U.S. to become the world’s top emitter in 2006. The report, to be published in the Journal of Environmental Economics and Management, estimates China’s …