Texas alone could hold 40 years' worth of US emissions.
Under a blazing west Texas sun, with a whiptail lizard and cattle looking on, Rebecca Smyth works with an assistant to lower a measuring line, then a hose, and finally a slender plastic capsule down an old water well 200 feet deep.
She's hoping the water samples she collects will yield clues to what is, arguably, one of mankind's most pressing environmental questions: Can nations bury their greenhouse gases?
If they can, then governments will have bought themselves a decades-long respite as they search for less carbon-intensive energy sources. If they can't, then a significant rise in global temperatures by 2100 looks inevitable, if fossil-fuel consumption continues at its current pace.
And the answer may well lie here, atop an old west Texas oil field known simply as SACROC, where more CO2 has been pumped underground over a longer period of years than anywhere else on Earth. Her efforts – and those of the rest of a small army of scientists funded by the US Department of Energy – are being closely watched. Energy companies want to know their options as Congress mulls over legislative options to global warming. Environmentalists are eager to find ways to slow the rise of greenhouse gases.
"If we don't sequester carbon from coal, we won't be able to stabilize the concentration of CO2 in the atmosphere," says John Thompson, director of the coal transition project of the Clean Air Task Force, a Boston-based environmental group. "It's the linchpin."
Admittedly, pumping huge amounts of carbon dioxide into underground caverns sounds audacious. If the US captured just 60 percent of the CO2 emitted by its coal-burning power plants and reduced it to a liquid for injection underground, the daily volume would roughly equal what the US consumes in oil each day – about 20 million barrels, according to a report by the Massachusetts Institute of Technology in Cambridge. And the risks are substantial.