Because of a mild winter, reduced demand for gasoline and, most significantly, a drop in coal-fired electricity generation because of historically low natural gas prices, we actually have hit a 20-year low in U.S. carbon emissions. In part, this is due to the energy efficiency in natural gas. While this appears as good news, we should be cautious as to what this really means for the long term. Reported by US Energy Information Administration. And a brief story on it here.