Perspective on the BP spill… How much is 4.9 million barrels of oil?
The news on the BP spill today was mixed. On the one hand, BP is finally pumping heavy drilling mud to seal the well for good. On the other hand, scientists in the Flow Rate Technical Group, supervised by the U.S. Geological Survey and the U.S. Department of Energy report that the”Macondo well spewed 62,000 barrels of oil a day initially, and as the reservoir gradually depleted itself, the flow eased to 53,000 barrels a day until the well was finally capped and sealed July 15″ (Washington Post). That leaves a total flow of 4.9 million barrels.
But how much is 4.9 million barrels?
We all clearly recognize that this is a very large number, but what we really need is perspective. To quote Anton Ego – the dynamic villain turned hero of Disney’s Ratatoille – “After reading a lot of overheated puffery… you know what I’m craving? A little perspective. That’s it. I’d like some fresh, clear, well seasoned perspective. Can you suggest a good wine to go with that?”
The fact is, humans are visual creatures. We have weak eyes, yet a significant portion of our brains is dedicated to deciphering visual cues. We think through visual metaphors. So, just as we have a difficult time imagining (note the root: image) the vast quantities of invisible methane that spewed out of the Macondo well along with the oil, we have a hard time envisioning just how much oil 4.9 million barrels is.
As if this visioning task was not difficult enough already, it has been made immeasurably more difficult by the numerous misleading maps like the popular NYT interactive graphic which shows the oil slick first as a growing 2-dimensional surface feature (the vast majority of the oil never made it to the surface so this is a gross misrepresentation of the spill) and later as a zero-dimensional image which seems to imply ‘problem solved’. When combined with the successful capping of the well, and the good news about the mud kill, I fear this story will soon vanish from the minds of the greater populous. And that will be a shame.
That said, let’s see if we can do some simple math and transform 5,000,000 barrels into a much more manageable figure… I’ve always been fond of the number ’2′. After all it is easy to remember and carries a certain mystique. For the biblically inclined, Noah led animals two by two onto the Arc. And for those with Darwinian inclinations that lean more towards evolutionism than creationism, our chromosomes also come in pairs (as do our jeans, but for some reason, I don’t think the fashion-inclined set reads my blog).
So there we have it. A goal. Express the oil spill in 2 tangible units.
In the quest for clarity, the first issue to address is the arcane use of the term ‘barrel’. Ask the average person how many gallons are in a barrel, and I bet you’ll get a wide range of answers. Some might envision a keg of beer, which is 15.5 gallons. Using the keg as a reference, these lightweights (my college buddies come to mind) would greatly underestimate the volume of the spill, though. Perhaps heavy drinkers with visions of whiskey barrels can provide a more accurate approximation to the number of gallons in a barrel of oil.
As it turns out, a barrel of oil is the same size as a barrel of whiskey – 42 gallons. And this is no accident. When the oil industry was still in its nascent state, whiskey barrels were used to transport oil from places like Titusville, PA to industrial hubs like Cleveland, OH (see my post on Cleveland’s flaming Cuyahoga River). In fact, so rapidly did the oil industry grow during the first oil boom (early 1860′s) that, “supply far outran demand, and the price plummeted. With the advent of drilling, there was no shortage of rock oil. The only shortage now was of whiskey barrels, and they soon cost almost twice as much as the oil inside them.” (The Prize, p. 28)
So there we have it. A barrel of oil is equal to 42 gallons, so we can now at least express the volume of oil spilled in a tangible unit – the gallon milk jug (or whiskey jug if you’re lactose intolerant).
I’m sure that all will agree that 205.8 million gallons (4.9 million times 42) is a lot of milk. In fact this amount is roughly equal to 4 months of milk production in the U.S.
Of course my goal is to get to the magical number ’2′, so this calculation certainly took us in the wrong direction. And if anything, I’m more amazed that 22 billion gallons of milk are produced every year than by the fact that the oil spill is roughly one-third this amount.
Well, we’ve all filled our car’s gas tank, so maybe we can get at a more tangible number if we figure out how many cars could fill up on 205.8 million gallons of gas (not that oil is gas, but I’m sure you’ll forgive this slight weakness in my metaphor).
If the average car holds 12 gallons of gas, and all were running on empty, then the total number of cars that could fill up on the amount of oil spilled into the gulf would be – hold your breath – 17.1 million! Well, 17.1 million is a far cry from the magic number ’2′ but at least the number is moving in the right direction and we still have something tangible to envision.
Think about that figure… 17.1 million cars. For perspective the number of passenger cars assembled in the U.S. in 2006 was 4.36 million, so 17.1 million cars would be equivalent to roughly four years of total output. That seems like a lot, right? By contrast, Japan produced 9.76 million cars, and China produced 5.23 million. So there we have it, the quantity of oil spilled from the Macondo well is roughly enough to fill the tanks of all new passenger cars produced in the U.S. and Japan (in 2006) in addition to about half of the cars produced in China. Wow. That is a lot of cars.
Now imagine all those cars lined up at the same gas station. How long would the line be?
If the average car is 16 feet in length, then a line of 17.1 million cars would be 273.6 million feet long. Oops, it looks like my visualization has taken two turns in the wrong direction: the number just got bigger, and the units went from cars to feet! I guess it could be worse, I could have told you the line would be 8.2 billion centimeters long!
Well, so much for the metric system. Let’s head back to the land of imperial rule (pun intended).
As it turns out, the line of 17.1 million cars would be 51,818 miles long, and as every geographer knows, the circumference of the earth is just under 25,000 miles which means that:
The amount of oil spilled into the Gulf of Mexico would fill the tanks of 17.1 million cars, and if all these cars were to line up at the same gas station, the line would wrap around the earth two times!
And there we have it, the magic number ’2′! How’s that for PERSPECTIVE!