And they conveniently IGNORED that fact that methane (natural gas) has TWENTY_FIVE (25) TIMES HIGHER green house effect, per volume, compared to carbon dioxide.
During each step of natural gas production, there is gas leaked out into the atmosphere. And even at the final step when gas is burned, there is roughly 10% of gas which is not burned and leaked into atmosphere.
In comparison, coal never releases CO2 until it is burned, and ONLY the part that is burned, ash that is not burned does not release CO2 either.
So if they are so concerned about global warming, they should worry about shale gas a lot more than coal.