In terms of climate impact, methane emissions from the natural gas industry largely, if not totally, offset reductions in carbon dioxide from using natural gas instead of coal, gasoline, diesel or heating oils. More methane is leaking than regulators estimate, and pound-for-pound, each puff of methane from the industry is 87 times more potent than carbon dioxide at trapping heat over 20 years, and 36 times more potent than carbon dioxide at trapping heat over 100 years. The conservative estimate from atmospheric measurements (not from inventorying) is that U.S. natural gas leakage in 2010, averaged over the country that year, amounted to over three percent of total 2010 production.
The Obama administration and many environmental organizations are making waves to reduce this leakage, but setting aside the effectiveness of any new rules, consider that in terms of CO2 alone, burning all the natural gas unleashed by fracking breaks the CO2 budget.
In order to have even a 75 percent chance to keep warming below 2 degrees Celsius (averting high risks of extremely dangerous and irreversible climate impacts, such as sea level rise, habitat destruction and extreme weather), then we must keep total CO2 emissions from 2015-2050 under about 440 Gigatonnes (Gt, or one trillion kilograms). With this number, we arrive at a reasonable CO2 budget.
Of course part of this “budget” of about 440 Gt CO2 would be spent ramping down and phasing out oil and coal. Even if we arrived at the end of burning coal by 2025 and burning oil products by 2035 – extremely ambitious global goals – doing so would amount to about 200 Gt CO2. Leaving, just 240 more Gt CO2 left in our budget.
It turns out that CO2 emissions from burning all the “conventional” natural gas alone would add 794 Gt CO2 – over three times the 240 Gt CO2 left in the “budget” for natural gas. Using U.S. Energy Information Association estimates, global sources of unconventional natural gas (i.e., shale gas, tight gas and coalbed methane, which require extensive fracking) would amount to about 5600 Gt CO2, if it is all burned. That’s over 23 times the emissions left in the budget for natural gas! In other words (assuming no conventional gas) almost all “technically recoverable” natural gas (about 22/23rds of it!) needs to stay underground.
Clearly, while it is true that natural gas emits less CO2 than oil and coal products, there is no room in the CO2 budget for widespread and intensive extraction of natural gas.
Beyond the issue of climate change, widespread and intensive drilling and fracking will create many more immediate problems and leave a legacy of drinking water contamination. As explained in our recent report, The Urgent Case for Ban on Fracking, these problems make it ever more clear that in order to address the problem of climate change, we need to completely ban fracking.
 Using recent global CO2 emissions to update: Schellnhuber, Hans J. et al. German Advisory Council on Global Change. “World in Transition – A Social Contract for Sustainability.” 2011 at 114.