“Natural gas is a much ‘dirtier’ energy source than we thought…”
In the thick of a Greenland summer of field work in 2015, Benjamin Hmiel and his team drilled into the massive ice sheet’s frozen innards, periodically hauling up a motorcycle-engine-sized chunk of crystalline ice. The ice held part of the answer to a question that had vexed scientists for years: How much of the methane in the atmosphere, one of the most potent sources of global warming, comes from the oil and gas industry?
Previously, geologic sources like volcanic seeps and gassy mud pots were thought to spit out about 10 percent of the methane that ended up in the atmosphere each year. But new research, published this week in Nature, suggests that natural geologic sources make up a much smaller fraction of the methane in today’s atmosphere. Instead, the researchers say, that methane is most likely attributable to industry. Added up, the results indicate we’ve underestimated the methane impacts of fossil fuel extraction by up to 40 percent.
That’s both bad news for climate change and good, says Hmiel, the lead author of the study and a researcher at the University of Rochester. Bad, because it means that oil and gas production has had a messier, bigger impact on the greenhouse gas budget than scientists knew. But Hmiel finds the result encouraging for almost the same reason: The more of the methane emissions that can be pinpointed to human activity like oil and gas extraction, the more control it means policymakers, businesses, and regulators have to fix the problem.
“If we think of the total methane in the atmosphere as slices of a pie—one slice is from ruminants, this other is from wetlands. The slice is we used to think was from geologic methane was too big,” says Hmiel. “So what we’re saying is that the fossil fuel pie slice is larger than what we thought, and we can have a bigger influence on the size of the slice, because it’s something we can control.”