Agence France-Presse: The natural gas system in the United States is leaking far more methane, a harmful greenhouse gas, into the air than official estimates say, according to research released Thursday. The report by researchers at seven major universities reviewed some 200 studies from the past two decades and found that the Environmental Protection Agency is missing leakage from various sources in North America, including faulty pipelines, wetlands, natural seepage from the Earth's crust and other sources. However,...