The shale gas boom, spurred by fracking and horizontal drilling, is bigger than anyone thought it would be. According to the U.S. Energy Information Administration, natural gas derived from shale now makes up a full half of U.S. natural gas production, says Scientific American. Shale gas wasn't supposed to make up such a large portion of our gas supply for another ten to twenty years.

Almost all of the natural gas produced in the U.S. is burned in the U.S., and the development of technologies to pull gas from shale has created a glut of cheap energy.* America's cheap gas is drawing foreign companies to U.S. soil, and it's helping the country hit carbon emissions reductions targets. Shale gas' rising significance is partly due to increasing amounts of the gas being extracted and partly due to declining production from other sources of gas.

Earlier this month the Environmental Protection Agency proposed new rules to help fight climate change. The draft rules outline how states will need to cut the carbon emissions coming from the energy sector by 30 percent below 2005 emissions levels.

At the time, journalists pointed out that the recent widespread turn within the American energy sector to burning natural gas rather than coal means that, for many places, carbon emissions have already dropped by as much as 15 percent below 2005 levels. The gas glut has already helped the U.S. energy sector halfway to the EPA's proposed goal.

Contined production of this cheap gas is key to the EPA's carbon reduction plan, says Scientific American. Like it or not, fracking, horizontal drilling and the shale gas boom are now a core component of America's energy system. But the idea that such a heavy reliance on shale gas can (or should) last has its own problems. Some of the best-producing wells are already facing depletion, says Scientific American, and as the gas gets harder to extract prices could go up. Fracking and shale gas also have their own issues, largely environmental, which Smart News has explored previously.