WASHINGTON (Reuters) - Human-fueled global warming has reached a "tipping point," according to a new survey of scientific research that found warming would continue even if greenhouse gas emissions halted immediately. "It would keep on warming even though we have stopped the cause, which is greenhouse gases from the combustion of fossil fuels," David Jhirad of the Washington-based World Resources Institute said on Wednesday.The rate of warming would be slower, Jhirad said in a telephone interview, but a kind of thermal inertia would ensure that global temperatures continue their upward trend.He referred to a report released by the nonprofit institute...