On August 4, Carol Browner appeared on ABC’s Good Morning America to push the claim from BP and the Obama administration that most of the oil from the BP oil spill in the Gulf of Mexico is “gone”. Here is how AFP described what she had to say:
About three-quarters of the oil spilled from the ruptured BP well in the Gulf of Mexico has disappeared, a top US official said Wednesday.
“The scientists are telling us about 25 percent was not captured or evaporated or taken care of by mother nature,” said Carol Browner, a top energy adviser to President Barack Obama, on the ABC network’s “Good Morning America” programme.
“This is an initial assessment by our scientists in the government and outside the government. We think it’s important to make this available to the public. That’s what we’ll be doing today.”
Well, maybe not all scientists “outside the government” agree with Browner’s description of the situation. In a report dated August 17 (pdf), scientists with the University of Georgia’s Sea Grant College Program provide their own analysis of the fate of the oil released in this massive spill. A press release accompanies the report:
A report released today by the Georgia Sea Grant and the University of Georgia concludes that up to 79 percent of the oil released into the Gulf of Mexico from the Deepwater Horizon well has not been recovered and remains a threat to the ecosystem.
The report, authored by five prominent marine scientists, strongly contradicts media reports that suggest that only 25 percent of the oil from the Deepwater Horizon oil spill remains.
“One major misconception is that oil that has dissolved into water is gone and, therefore, harmless,” said Charles Hopkinson, director of Georgia Sea Grant and professor of marine sciences in the University of Georgia Franklin College of Arts and Sciences. “The oil is still out there, and it will likely take years to completely degrade. We are still far from a complete understanding of what its impacts are.”
Yes, that’s right. Carol Browner claimed 75 percent of the oil is “gone” and the Georgia Sea Grant scientists inform us that their analysis says that up to 79 percent of the oil released into the Gulf is still there.
In their analysis, the Georgia scientists began by agreeing with the National Incident Command report on how much oil came out of the wellhead:
There was consensus within the group that, as stated in the NIC report, approximately 4.9 million barrels emerged from the wellhead between the rig explosion on April 20, 2010 and the final capping of the well on July 15 2010.
They then noted that 17 percent of this oil, or 0.8 million barrels, was captured directly and never entered the waters of the Gulf. The captured oil was excluded from their analysis.
The scientists then proceeded to compare their analysis of the fate of the oil with that in the NIC report. Here is their summary of the NIC data:
Next the scientists accepted at face value the claim from the NIC report that 10 percent of the released oil was burned or skimmed. Where they begin to differ from the government’s claims, though, is when they assess the fate of the remaining 90 percent of the oil that was released into the water:
WHAT HAS HAPPENED TO THE UNRECOVERED 90%?
The NIC report states that oil released into the water, that has not been contained by skimming or burning, is currently in one of four states:
1) dispersed as micro-droplets,
2) dispersed as micro-droplets with dispersant coating,
3) dissolved (some of which has evaporated) and
Together, these forms make up the unrecovered 90%. The news media’s tendency to interpret “dispersed” and “dissolved” as “gone”is wrong. Dispersed and dissolved forms can be highly toxic. Furthermore, sorting the oil into the four above states falls far short of assessing how much of it remains a potential threat to the system.
Fortunately, natural weathering processes ARE degrading and evaporating the various compounds that make up what we collectively call crude oil, and certainly a significant fraction of the unrecovered oil has been removed from the Gulf through evaporation or degraded into harmless forms. The following is this groups attempt to estimate how much.