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The oil and dispersants in the Gulf are enough to worry about, but why is no one talking about the methane from the spill possibly reaching the atmosphere? Could this have an effect on climate change? And if so, shouldn't BP be liable not only for the damage caused by oil, but for the potentially massive greenhouse impact?
Methane. Long associated with bovine burps and putrid landfills, it's what triggered the explosion that caused the Deepwater Horizon to burn and sink in the first place, unleashing a torrent of crude into the Gulf of Mexico 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 scientists, the mixture spewing from the ocean floor is about 40 percent natural gas (read: mostly methane), and 60 percent petroleum compounds.
Just to refresh your memory, methane is a greenhouse gas that is 23 times more powerful than carbon dioxide. According to the Environmental Protection Agency, methane concentrations in the atmosphere have more than doubled over the past two centuries, mostly due to human activity.
A potent greenhouse gas. That makes up close to half of the recently revised estimate of the 35,000 to 60,000 barrels of oil leaking each day. Of which an unknown portion is escaping into the atmosphere. You're right to ask: 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," he says. "This will exacerbate the greenhouse effect."
How much so, though, 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 flared natural gas figure reported by BP on June 14: 33.2 million cubic feet. (Keep in mind that this is based on the 15,420 barrels of oil BP claimed to collect that day; it doesn't account for the potential methane emissions associated with the oil that was not collected.)
Using the EPA Interactive Units Converter:
1 cubic foot (CF) methane (CH4) = .04246 pounds of CH4
33.2 million CF CH4 x .04246 = 1,409,672 pounds CH4 = 639.4 metric tons CH4
639.4 metric tons CH4 = 13,427.4 metric tons CO2 equivalent a day
For comparison, that's more than 80 percent of daily CO2 emissions for the entire New York metro area.
Of course, I'm neither scientist nor mathematician, which is why I'll be closely following the results of a team of researchers currently studying the methane leaking from the Deepwater Horizon disaster site. The group, led by Texas A&M College of Geosciences chief scientist John Kessler, hopes to uncover (along with other important data, like the precise amount of oil that has spilled) just how much of the greenhouse gas is being released into the atmosphere.
Should the spill be deemed a contributor to climate change, however, count it highly unlikely that BP will be held accountable. If Washington can't agree on a price point for carbon pollution, monetizing methane doesn't stand a chance.
Besides, getting BP to pay every penny for the damage that is measurable (like lost jobs) will be challenging enough, despite the president's insistence to the contrary: Twenty-one years after the Valdez oil spill, ExxonMobil still owes $92 million.
BP CEO Tony Hayward, however, has repeated his promise that the company will pay all "legitimate" claims arising from the Gulf spill. Let's hope that methane is the only hot air the company is spewing.
An abbreviated version of this article originally appeared on The Red, White and Green.
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