Single US oilfield raises global level of pollutant ethane by 2%: Study
A single US oil and gas field is the main culprit in the global uptick of the air pollutant ethane during the last six years, says a new study.
In an article to be published by the Geophysical Research Lettersjournal, a team of scientists from the University of Michigan, Stanford University, NASA, and NOAA revealed that fossil fuel production at the Bakken Formation located in North Dakota and Montana states is responsible for the emission of roughly two percent of the hydrocarbon detected in the Earth’s atmosphere.
“Two percent might not sound like a lot, but the emissions we observed in this single region are 10 to 100 times larger than reported in inventories. They directly impact air quality across North America. And they’re sufficient to explain much of the global shift in ethane concentrations,” said Eric Kort, a UM assistant professor of climate and space sciences and engineering, and the leading author of the study.
Ethane, which gets into the air mainly through leaks in fossil fuel extraction, processing and distribution, is a significant component of the natural gas. Once present in the atmosphere, it reacts with sunlight to produce ozone, which in turn can cause asthma attacks and other breathing malfunctions, particularly in children and the elderly.
The global levels of the hydrocarbon were in downswing between 1984 to 2009. The reason for the decrease was attributed to less venting and flaring of gas from oilfields and leakage from production and distribution systems.
In 2010, however, a mysterious ethane uptick was detected in Europe. Scientists, then, hypothesized that a boom in the US oil and gas brought about by hydraulic fracturing could be the reason for increasing levels of the pollutant in the atmosphere.
After collecting airborne data over the Bakken Formation’s oil production areas for 12 days in May 2014, they discovered that the oil industry facilities in the region add some 250,000 tons of ethane per year.
“These findings not only solve an atmospheric mystery–where that extra ethane was coming from–they also help us understand how regional activities sometimes have global impacts. We did not expect a single oilfield to affect global levels of this gas,” said co-author Colm Sweeney, a scientist from NOAA.
According to the study, this recently developed large ethane source from one location shows the key role of shale oil and gas production in increasing global ethane levels.