It is ironic that the "drill baby drill" attitudes of conservatives led to fracking, thus cheap natural gas displacing coal, which drastically lowered greenhouse gas emissions.
Natural gas is mostly methane. Methane is a potent GHG, far stronger than CO2. During fracking and so on, lots of natural gas (methane) escapes to the atmosphere. It is a gas, after all. A proper accounting would add in this other set of emissions.
So yeah, saying that natural gas usage "drastically lowered GHG emissions" is kind of suspect. Maybe it is better on balance vs. coal, but that is not saying a lot.
A study was released late last year by the National Centre for Atmospheric Research (NCAR) [1] which found that a switch to natural gas would increase warming over the next few decades, as outlined in NCAR's report [2].
It acknowledges something the shale gas industry studiously avoids in calculating figures for its green credentials pitches: fugitive emissions. A significant amount of methane leakage occurs in the fracking process and piping of gases.
When you add in the input-intensive activity of multiple well constructions, fracking, pipeline construction, and fugitive emissions the 'green' story of shale gas doesn't add up.
There was a piece recently on another atmospheric scientist coming to the same conclusion. She uncovered significant underestimation of fugitive emissions of methane (speculating that it is at least double the official figures) and concluded that they are also underestimating release of other chemicals. [3]
[1] http://www.springerlink.com/content/b430681263425q64/?MUD=MP
[2] https://www2.ucar.edu/atmosnews/news/5292/switching-coal-nat...
[3] http://www.npr.org/2012/05/17/151545578/frackings-methane-tr...
Irony requires a reversal of expectations. The logical expected consequence of drilling is increased greenhouse gas emissions. What in fact happened was the reverse. This is textbook irony.
http://en.wikipedia.org/wiki/Arctic_National_Wildlife_Refuge
Because ANWR would supply petroleum (a fuel mostly used for transportation and scarcely ever used for generating electricity), it has virtually nothing to do with the market for coal (which is used almost entirely for generating electricity), or disruptions to that market caused by a growing reliance on natural gas (which is also frequently used for heating, but remains uncommon in the transportation market).
And because transportation networks and electrical grids have so little overlap in terms of power supplies, policy choices made about Alaskan petroleum have little direct connection with policy choices related to fracking for natural gas. So no, there is no irony in any of this. The word is simply inapplicable.