Maybe natural gas is not the savior

That's the opinion - and belief - of Anthony R. Ingraffea, a professor of civil and environmental engineering at Cornell University.  He makes a strong case, based largely on the fact that natural gas wells leak methane and other contaminants outside their casings and into the atmosphere and water wells.

"Methane is a far more powerful greenhouse gas than carbon dioxide, though it doesn’t last nearly as long in the atmosphere. Still, over a 20-year period, one pound of it traps as much heat as at least 72 pounds of carbon dioxide. Its potency declines, but even after a century, it is at least 25 times as powerful as carbon dioxide. When burned, natural gas emits half the carbon dioxide of coal, but methane leakage eviscerates this advantage because of its heat-trapping power."

Ingraffea claims that many studies show that 5% of new gas and oil wells leak immediately after being opened.  And, over time the concrete in these wells starts disintegrating.  NOAA has done a study that shows leakage rates of 2.3 percent to 17 percent of annual production of oil and gas.  A 2011 study from the National Center for Atmospheric Research concluded that unless leaks can be kept below 2 percent, gas lacks any climate advantage over coal.