DENTON, Texas — Natural-gas wells here can be found just beyond the hedgerows of new subdivisions, and close by the hangars at the municipal airport. Their tunnels extend deep underneath a city park, a golf course and the University of North Texas football stadium.
The wells draw from the Barnett Shale, a geological formation once thought too dense to be profitably tapped for energy. Then, in 1997, crews deploying water under high pressure with chemicals and sand learned how to fracture the shale rock and release vast new supplies of natural gas — a process known as fracking.
That technology has reshaped America’s energy industry, with shale gas now produced in more than a dozen states. And, President Obama is touting the expansion in natural-gas-generated electricity, which produces roughly half the carbon emissions of coal, as a bridge to the nation’s energy future.
But natural gas is no long-term fix in the effort to shield the world from the most severe effects of climate change or meet the difficult goal set by Obama and other world leaders to keep global temperatures from rising no more than 2 degrees Celsius.
Some experts say unfettered burning of natural gas, without adding systems to capture carbon emissions, will significantly undermine that effort.
“Gas may be the cleanest of fossil fuels, but it is still a fossil fuel,” said Maria van der Hoeven, executive director of the International Energy Agency, in a July speech. “The widespread use of gas without emissions abatement would leave us with no chance of meeting our 2- degree climate goal.”
The ability of natural-gas use to combat climate change is further eroded by leakage from the production, processing and transport of the fuel. Methane is the primary component of natural gas, and when vented rather than burned for energy, it acts as a short-lived but potent greenhouse gas.
The sheer abundance of natural gas also could work against efforts to limit climate change. If big supplies keep prices low, then natural gas could slow the development of alternative sources of energy that could help meet the 2050 goals.
A study released in 2013 by Stanford University’s Energy Modeling Forum found that natural gas in the decades ahead is likely to replace not only high-carbon coal but also zero-carbon fuels like nuclear, which now provides nearly 20 percent of the nation’s electricity.
Last year, for example, a nuclear-power plant in Wisconsin shut down because it could no longer compete in markets driven down by low-cost natural gas. More nuclear-plant closures are forecast in the years ahead.
Tracking these trends, the Stanford study concluded that a surge in natural-gas use spurred by the fracking technology would have “relatively modest impacts” on carbon emissions through 2050.
“You might see some downturn, but it’s not any kind of a game changer,” said Hillard Huntington, executive director of Stanford University’s Energy Modeling Forum. “Shale gas development is not a big winner from a climate point of view.”