Caring about the environment is patriotic.
Methane. It’s what led to the explosion that caused the Deepwater Horizon to burn and sink in the first place, unleashing a torrent of crude into the ocean that has now surpassed the Exxon Valdez as the worst oil spill in United States history. The gas is also still being released along with the oil: According to BP, the mixture spewing from the ocean floor is about half methane and other gases, and half petroleum compounds. Oh, and it’s a greenhouse gas that’s 23 times more powerful than carbon dioxide.
A powerful greenhouse gas. That makes up half of the estimated 500,000 to 1 million gallons of oil leaking each day. Of which an unknown portion is escaping into the atmosphere. Why is no one talking about this?
When I contacted Jeff Chanton, a professor in the Department of Earth, Ocean, and Atmospheric Science at Florida State University who has been closely following the BP spill, he was quick to point out that the immediate short-term threat to the ecosystem in the Gulf, is, of course, the oil itself. But, he says, “Methane is undeniably bubbling out with this oil and escaping to the atmosphere. This will exacerbate the greenhouse effect.”
How much so is not so clear. Based on Chanton’s recent research looking at natural oil seeps on the sea floor, he estimates that anywhere from 10 to 50 percent of the methane released might make its way into the air. This, he says, is because the oil actually forms a protective coating around the methane bubbles, allowing the gas to escape to the surface instead of being dissolved in seawater and consumed by natural methanotrophic bacteria.
“We looked at several sites this past summer, and at one of the sites, the natural seep was very oily,” he says. “At the site that was very oily, we did find elevated methane concentrations in the atmosphere over the site. But another site that was more shallow, where the bubbles were not oily, we didn’t see that. So the oil helps the methane get to the surface by kind of armoring the bubbles and then they don’t dissolve as much.”
So now, for the holy cow analysis: For calculation’s sake, let’s use the natural gas leakage figure given last week by BP: 15 million cubic feet a day (although based on BP’s oil spill estimate at that time of 5,000 barrels a day, that figure is probably a lot higher).
According to the EPA Interactive Units Converter:
1 cubic foot (CF) methane (CH4) = .04246 pounds of CH4
For comparison, that’s more than a third of daily CO2 emissions for the entire New York metro area.
Any other number crunchers want to take a crack at it?