The Dirty ‘Clean Fuel’: Why Natural Gas Out-Pollutes Coal
An illustration of the Atlantic margin showing the relationship between methane seeps and seafloor features.
Credit: A. Skarke and C. Ruppel/Nature Geoscience Enlarge
By Jeremy Deaton, Nexus Media:
Jeremy Deaton writes about the science, policy and politics of climate and energy for Nexus Media. You can follow him at @deaton_jeremy. He contributed this article to Live Science’sExpert Voices: Op-Ed & Insights.
Climate activist and author Bill McKibben has likened 2 degrees Celsius (3.6 degrees Fahrenheit) of warming to the legal drinking limit, and the global carbon budget to a six-pack shared between friends. The total proven coal, oil and gas reserves? That’s “the three 12-packs the fossil-fuel industry has on the table, already opened and ready to pour.”
Sixty to 80 percent of the coal, oil and gas reserves of publicly listed companies need to stay in the ground if the planet is to have a decent shot of keeping global warming to less than 2 degrees C above pre-industrial levels, the limit agreed to by world leaders. Extending McKibben’s analogy, coal is the moonshine of fossil fuels — cheap, dirty and extremely dangerous. Oil is an off-brand whiskey. Natural gas is Grey Goose vodka — clean, refined and widely unobjectionable. It should appeal to free-market libertarians and left-leaning environmentalists alike. That’s received wisdom, anyway. In actuality, natural gas simply poses a different range of threats. Gas may be just as hazardous as oil and coal.
1. Natural gas is mostly methane.
Natural gas produces about half as much carbon dioxide as coal, but it can wreak havoc if it escapes into the atmosphere unburned. That’s because natural gas is comprised mostly of methane, an extremely potent greenhouse gas. Over the course of a century, methane will trap 34 times as much heat as an equivalent amount of carbon dioxide.
Problematically, natural gas is prone to leaking from pipelines, wellheads, and the nooks and crannies of processing and storage facilities. “Accounting for methane leakage throughout the supply chain of natural gas, natural gas might actually be worse for the climate than coal,” said Lena Moffitt, director of the Sierra Club’s Stop Dirty Fuels Campaign, at a panel on energy hosted by Politico.
As NOVA Next reported, it’s conceivable that leaked methane from the U.S. oil and gas sector is warming the atmosphere as much as America’s 557 coal-fired power plants. [Nearly 6,000 Natural Gas Leaks Found in Washington, D.C. ]
Thus, while the United States’ embrace of natural gas has cut carbon dioxide emissions, the country might not have put a dent in total greenhouse gas emissions, which include methane.
2. Gas pipelines blow up.
Shoddy pipes don’t just deliver climate-distorting methane into the atmosphere. They also endanger people who live nearby. In recent years, natural-gas pipeline explosions have killed five in Allentown, Pennsylvania; eight in San Bruno, California; and 10 in southeast New Mexico, to name a few. Now, thanks to the shale gas boom, thousands of miles of new gas pipelines are wending their way across the country.
Pipes, known as “gathering lines,” carrying gas from wells to processing facilities are just as vulnerable to deterioration and natural disasters as are other kinds of pipelines. But a significant portion are exempt from federal safety or construction regulations because they traverse rural areas, and are therefore seen as posing a less significant threat.
This regulatory wrinkle puts countless rural families at risk.