To Frack or Not to Frack For Natural Gas

Scientific American published this article on the growth in the volume of natural gas produced by hydraulic drilling in shale (fracking). It has increased from 1% of gas production to 30%. This is good for the environment since the burning of gas releases less CO2 than coal, but there are many unresolved safety issues that are discussed in this article. The major issue is about the impact on underground water pollution.