We reported previously on a Cornell study claiming that natural gas development will likely contribute more to global warming than burning coal (see here). The Patriot-News is now reporting on the conclusions reached by scientists at Carnegie Mellon University: "The peer-reviewed study published Aug. 5 in 'Environmental Research Letters' appears to be a direct refutation of an April study from researchers Robert Howarth and Anthony Ingraffea at Cornell University that indicated that shale gas was worse for global warming than coal." Looking specifically at Marcellus shale development, it finds that "Marcellus gas is essentially no different than conventional natural gas, the study found, and 20-50 percent cleaner than coal for producing electricity."