Gas not as clean as we think

Extracting natural gas from shale could do more to aggravate global warming than mining coal, according to a Cornell study published in the May issue of the peer-reviewed journal Climatic Change Letters. While natural gas has been touted as a clean-burning fuel that produces less carbon dioxide than coal, ecologist Robert Howarth warns that we should be more concerned about methane leaking into the atmosphere during hydraulic fracturing.