It also releases a good 5% of the gas that goes through the well uncaptured and unburned into the atmosphere, according to a recent paper I saw in Nature. As methane is many many times as potent at retaining atmospheric heat as CO2 on a timescale of decades, this makes energy gained by fracking worse than coal in the net in terms of greenhouse effect (rather than simply CO2 emissions).
It also releases a good 5% of the gas that goes through the well uncaptured and unburned into the atmosphere, according to a recent paper I saw in Nature. As methane is many many times as potent at retaining atmospheric heat as CO2 on a timescale of decades, this makes energy gained by fracking worse than coal in the net in terms of greenhouse effect (rather than simply CO2 emissions).
There are also studies showing a strong correlation between distance to well-bores and dangerous methane levels in well water, contrary to industry reports. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100993/