In April, Bob Howarth and two of his colleagues at Cornell University published a report in the journal Climatic Change, with this conclusion:
Natural gas is a dirtier fuel source than coal or oil.
The piece caused an uproar among energy analysts, industry insiders and researchers, and the result is a new article - set to come out in the same journal - by another Cornell professor, that directly contradicts the initial study:
Natural gas is a cleaner source of energy than coal.
And it's panning out to be a showdown.