Air Date: Week of May 28, 2010

Atmospheric Scientist Kerry Emanuel. (Photo courtesy of: Donna Coveney MIT News Office)

If oil and water don’t mix, what happens when you add a hurricane? Living on Earth’s Bruce Gellerman whips up an experiment in his kitchen to see if the upcoming tropical storm season and Gulf oil gusher is a recipe for disaster. . .or dessert.

Transcript

YOUNG: It’s Living on Earth, I’m Jeff Young. The Atlantic hurricane season begins June first and forecasters predict an above-average season with 23 named storms, including 14 hurricanes. All the ingredients are there: Atlantic sea-surface temperatures are at near record highs and Pacific waters are cooler following last year’s el Nino.

But this year there are two new ingredients in the mix: millions of gallons of oil and thousands of pounds of chemical dispersants swirling in the Gulf of Mexico. As Living on Earth’s Bruce Gellerman reports this could be a recipe for even greater environmental disaster—or perhaps—a perfect storm that ends up helping.

[SOUNDS OF INDOOR POOL]

GELLERMAN: You know how you get a chill when you come out of a swimming pool.

[SOUNDS OF CLIMBING OUT OF POOL]

GELLERMAN: That’s because of evaporation, and evaporation is the same process that’s the source of energy that drives hurricanes. In summer, solar energy heats the tropical seas. The warm water evaporates and cools, and the energy flows from sea to sky, spawning storms. Kerry Emanuel, professor of atmospheric science at MIT, wanted to study this process, so he built a mini Gulf of Mexico.

EMANUEL: Yes we did, some years ago in a laboratory. We built a laboratory apparatus to study how heat is transferred from the ocean to the atmosphere when wind blowing at hurricane force. And we were interested in this because that heat flow is what powers hurricanes.

GELLERMAN: When the experiment was just about finished Professor Emanuel asked himself a question: What would happen if he added oil to the water? Would the slick on the surface absorb more solar energy and increase the power of a hurricane? Or could an oil spill block evaporation and stall the formation of a storm?

EMANUEL: There’s work going back to the 1960’s that suggested that we could put oil on troubled waters and thereby slow down a hurricane.

GELLERMAN: Emanuel’s team set out to create an oil spill in their lab and test if the slick could stop a storm in its tracks.

EMANUEL: And so we tried various substances: olive oils, fish oils, you know various kinds of organic oils. And they do curtail evaporation at low wind speed but once the winds really start to blow the films start to break up and cease to have an effect.

GELLERMAN: In the lab the oil slick didn’t disrupt hurricane formation, but the experiment did show that when it blows 74 miles an hour—the minimum speed for a hurricane - the churning action of wind and waves speeds up the breakdown of the oil, which is good if you have a giant gusher, like the one now polluting the Gulf. What researcher Kerry Emanuel didn’t test was the effect of an ingredient BP is adding to the disastrous Deepwater Horizon spill: dispersants. So my kids and I tried a simple experiment of our own:

GELLERMAN: Ok so here we are in our laboratory better known as our kitchen. And let’s see, here is our…

ANDRE: Blender.

GELLERMAN: Ok, we’ll use that as our ocean. And here is our:

ANYA: Olive oil!

GELLERMAN: That will be our oil spill.

ANYA: That’s so cool.

GELLERMAN: And it’s all coming to the surface…and you take our surfactant.

ANYA: Dishwasher soap.

GELLERMAN: A little squish, and we’ll add a hurricane.

[SOUNDS OF BLENDER]

ANYA: Oh my gosh! [Laughs] Wow.

ANDRE: It looks like milk.

ANYA: Yeah it does. It looks like a milkshake. Is that what happens when it like mixes together?

GELLERMAN: Under certain conditions yes. It’s what happened 21 years ago when the Exxon Valdez dumped 11 million gallons of crude into Alaska’s Prince William Sound. Dispersants were used. Two days later a blustery storm just under hurricane speed blew in—blending: sea, oil, and chemicals. It was a recipe for a disaster.

PEGAU: The storm emulsified the oil so what it did was make it a real foamy mess.

GELLERMAN: Scott Pegau is research program manager for the Oil Spill Recovery Institute in Cordova Alaska. The institute funds research on Arctic and sub-Arctic oil spills in marine environments. Pegau says in the aftermath of Valdez scientists came up with a new technical term for the stuff whipped by the storm. And the name, like the goo, stuck: Mousse.

PEGAU: Mousse, as in like the dessert, but not as nice.

GELLERMAN: What was the effect of having this mousse?

PEGAU: The mousse is more difficult to clean up. You don’t have a lot of your options. So, you can’t burn it. You have to use different mechanical equipment to help pick it up because it has a different viscosity to it. But with the Exxon Valdez you had so much oil come out at that one time it was going to be hard one way or another.

GELLERMAN: Scientists don’t expect a storm will create as much oily mousse from BP’s well as the Valdez disaster. The Gulf is larger, the oil is lighter, and the slick thinner and more spread out. The situation today is actually closer to what happened in 1979 when Mexico’s Ixtoc One rig blew up off the coast of the Yucatan, dumping 140 million gallons of oil into the Gulf.

The crude coated the Texas coast. And two months later a tropical storm blew through. But to the surprise of many scientists it cleaned up much of the oil that washed ashore, though it also created tar reefs off shore that would break into pieces in later storms coating beaches with goo for years to come.

A hurricane will certainly disrupt the Deepwater Horizon clean-up effort and the fear now is that a storm surge—driven by a hurricane’s intense winds—could drive a wave of oily water far inland. Professor Piers Chapman, head of the department of oceanography at Texas A&M recalls the surge accompanying Hurricane Rita in 2005:

CHAPMAN: The water from Rita ended up pretty much on I-10, which was 20 to 30 miles inland.

GELLERMAN: This is supposed to be a pretty active hurricane season?

CHAPMAN: Yes, that’s the worry.

GELLERMAN: Every tropical storm is unique and unpredictable, and millions of gallons of oil and chemical dispersants above and below the Gulf add to the complexity. Making this year’s hurricane season a giant, closely watched experiment of enormous importance. For Living on Earth I’m Bruce Gellerman.