Natural gas may be plentiful, cheap and inviting at the moment. But the fracking process to get it still fans the flames of environmental policy clashes.At the Wall Street Journal’s ECO:nomics conference outside Santa Barbara, Calif., drillers and environmentalists debated over whether fracking posed a danger to the communities they serve. Drillers said that the amount of natural gas available –4,000 trillion cubic feet — can’t be ignored.“There is so much there, which is shown by what prices are,” said Edward Cohen, chief executive of Atlas Energy .But Paul Gallay, president of the environmental group Riverkeeper, challenged Cohen and Aubrey...