Close to 5,000 barrels of oil a day are pouring into the Gulf of Mexico following the destruction of an offshore oil platform last week, according to the U.S. Coast Guard. Operator BP originally argued that the amount was far less (only 1,000 barrels or so), but today it concurred with the government's numbers.
Too bad they're both wrong, according to a group of independent analysts who are watching the spill via satellite and aerial data from their offices in West Virginia. They say the spill is far worse than either the company or the government has acknowledged so far.
Five thousand barrels a day is "a bare-bones limit," says John Amos, the president and founder of the nonprofit firm SkyTruth, which specializes in gathering and analyzing satellite and aerial data to promote environmental conservation.
Amos estimates that the amount of oil leaking into the Gulf is more like 20,000 barrels a day -- four times the Coast Guard estimate, and 20 times what BP originally claimed. That would add up to about 6 million gallons of oil so far. With oil still flowing, this spill threatens to be worse than the 1989 wreck of the Exxon Valdez, which dumped 11 million gallons into Alaska's Prince William Sound -- one of the nation's worst environmental disasters. (NRDC is calling for a temporary halt to plans for new offshore drilling in light of the Gulf explosion. See update below on President Obama's response.)
Amos previously worked as a consulting geologist, "using satellite imagery as a global geologic tool," in his words, to locate natural resources for major oil and mining corporations. Now he assists advocacy organizations, government agencies, and academic researchers with data collection and analysis.
SkyTruth receives a bit of foundation funding, and it also partners with green groups in the United States and overseas on specific projects. Last year, when a Montara oil rig exploded in the Timor Sea off the northern coast of western Australia, SkyTruth tracked and documented the spill for a coalition of groups advocating for protected marine reserves in the area. That spill lasted for 10 weeks.
"On this Gulf spill, we're not officially partnered with anyone," Amos says. "We are doing what we think is the best thing we can do right now, hoping at some point groups will work with us to make it sustainable over the long haul." He's assisted by a technical volunteer and consultations with professional cohorts.
The Deepwater Horizon drilling platform, about 130 miles southeast of New Orleans, exploded and caught fire on April 20 and sank a week ago today. There were 126 people on board; 11 are missing and likely dead. Louisiana Gov. Bobby Jindal declared a state of emergency today because of the spreading oil slick -- which is expected to reach the state's coast late tonight -- and Homeland Security Secretary Janet Napolitano called it a spill of "national significance."
SkyTruth has access to much of (but not all) the same data that the government and BP are using. It's publicly available from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the agency's Aqua satellite, as well as other sources, including aerial flights.
Based on a map released from a flyover on Wednesday and compared to "the last good satellite image that we got, from the afternoon of April 27," Amos believes that the slick covers about 2,300 square miles. Official estimates to date have put the slick at about 2,200 square miles.
So how did Amos calculate the amount of oil leaking into the Gulf?
"We saw a published statement by a BP executive that about 3 percent of the slick was about 100 microns thick, and that the rest was about one or two molecules thick," he says. "We took him at his word on the microns, but not on the rest," because to see an observable sheen of oil at sea, the petro-goo needs to be at least 1 micron thick, explains Amos.
"A molecule's thickness is measured in billionths of a meter. For a micron, we're talking millionths of a meter," he says. And over thousands of square miles of ocean surface, even millionths of a meter add up.
Using BP's estimate that 3 percent of the slick's area is 100 microns thick, with an area of 2,200-2,300 square miles, Amos calculated that this part of the spill contains about 4.5 million gallons of oil.
Allowing for the remaining 97 percent of the slick to be 1 micron thick (the minimum necessary for that visible shimmer), Amos estimates another 1.5 million gallons of oil.
Total: 6 million gallons of slick, give or take a couple hundred thousand, and more oil pouring into the ocean every day.
To make even a rough estimate, Amos used BP's higher-end figure of 100 microns. But the oil is actually much thicker in some parts of the visible spill, he says. Aerial imagery is showing "thick ropy strands of oil, oil that's much thicker than 1 micron," according to Amos. "That's floating froth of oil mixed with water and probably bacteria ... the sloppy thick end of an oil spill where it could be anywhere from a millimeter thick to centimeters thick."
Amos says he doesn't question the Coast Guard's sincerity -- just its data analysis. "They are swamped by the magnitude of this spill and their effort to control it, and stop it from doing worse damage," he says. "I don't blame them for not questioning the numbers they've been provided by others, or spending their precious resources just trying to come up with better number."
From the Coast Guard's perspective, Amos say, "It's just a heck of a lot of oil."
The Coast Guard has not responded to requests for comment.
As for how BP arrived at its initial, much lower estimate of 1,000 barrels per day, Amos says: "I hope it was based on some real thoughtful analysis. But I haven't seen any justification."
UPDATE 4/30/2010: In response to calls from NRDC and others for a halt to drilling expansion in light of the latest disaster, the White House said today that no new offshore oil drilling will take place until a full investigation into the Deepwater Horizon explosion is completed. ~ Emily Gertz April 29, 2010 on Onearth.org
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