November 30, 2013

Saturday Morning Essay: Dispatch From the East Siberian Arctic Shelf

Brought to you by three gallons of Peet's Coffee....

I think that's it.  It could be East Arctic Siberian Shelf. Or East Siberian Arctic Shelf.  I can't think straight right now because my head's frozen.  I understand, and accept, that the Arctic is warming at a rate about 3 or 4 times faster than the globe generally, but it's still colder than a well digger's nuts up here.

I'm waiting for Natasha to show up. You know her as Natalia Shakhova.  I call her Natasha, but on the other hand she thinks my name is Boris.  It's a private joke that only one of us is in on.  My reference is obviously to Rocky & Bullwinkle, but Natalia is Russian, for real, and I'm not, even if I've gotten in the habit of starting all of my sentences, when I speak to her, with "is." 

I'm wearing a wetsuit and standing on squishy ground on the shore of the Laptev Sea.  This is real Solzhenitzen country out here, bleak, windswept, desolate, with the Arctic, covered with a thin layer of ice, stretched out before me.  Yes, I have a tuxedo on under the wetsuit.  As if you needed to ask.  I don't know what Natalia will be wearing.  I know it will be something pretty good.  Global warming was a good field for her, because she's hot.

Natalia is the lead author on a couple of recent papers on Arctic methane.  Her work was reviewed by David Archer of the University of Chicago on the blog.  David happens to be my prof on the course I'm taking on global warming.  I knew all of this couldn't be a coincidence, so I called Natalia and made sure she knew about David's analysis (she did, of course), and pointed out the intriguing point Professor Archer had made about methane hydrates in the Arctic Sea.
Methane hydrate seems menacing as a source of gas that can spring aggressively from the solid phase like pop rocks (carbonated candies). But hydrate doesn’t just explode as soon as it crosses a temperature boundary. It takes heat to convert hydrate into fluid + gas, what is called latent heat, just like regular water ice. There could be a lot of hydrate in Arctic sediments (it’s not real well known how much there is), but there is also lot of carbon as organic matter frozen in the permafrost. Their time scales for mobilization are not really all that different, so I personally don’t see hydrates as scarier than frozen organic matter. I think it just seems scarier.

The other thing about hydrate is that at any given temperature, a minimum pressure is required for hydrate to be stable. If there is pure gas phase present, the dissolved methane concentration in the pore water, from Henry’s law, scales with pressure. At 0 degrees C, you need a pressure equivalent to ~250 meters of water depth to get enough dissolved methane for hydrate to form. 

Let me jump to the conclusion: Mr. Archer doesn't think you're going to find methane hydrates in 50 meters of water, and that's supposed to be the scary part about the East Siberian Arctic Shelf - all that methane locked up in ice "cages" in shallow water along the largest continental shelf in the world, losing its ice cover, exposed to heat conducted downward from the dark surface of the water.  Yeah, like pop rocks, alright: fiizzzzzzzz! Those hysterics over at the Arctic Methane Emergency Group have been free-riding on some of Natalia's research and talking about a "methane bomb" in a 2013 paper, although Natasha herself, ever demure and scientific, doesn't go there.

So Prof. Archer asks the question:  

But these experiments spanned 100 hours, while the sediment column has been warming for thousands of years, so the experiments do not really address the question. I have to think that if there were some impervious-to-melting hydrate, why then would it suddenly melt, all at once, in a few years? Actual samples of hydrate collected from shallow sediments on the Siberian shelf would be much more convincing. 

One answer that occurred to me:  because the melting of the Arctic ice cap has occurred over a few years?  But David Archer must be aware of this.  Although he makes me a little nervous when he says that he would not be concerned with methane emissions in the Arctic unless they increased by "an order of magnitude."  Uh, my gal Natasha's work records that the methane vents in the Arctic increased in size from a meter across to a kilometer across.  I think that's 3 orders of magnitude.  Nevertheless, Mr. Archer is right: why not just go down in the goop and grab a handful of Arctic sediment and see what's in it?

You rang?

"Is thinking we dive down and grab handful," I said.  I'm wearing a black Borsalino just to be in character, although I'm talking on the phone.

"Is yes," Natalia says. 

So here we are on the shore.  Natalia shows up, but she's got that guy Semilitov with her, the Russian climate scientist who takes all those cruises with her around the Arctic during the summer, counting methane bubbles.  They're both decked out in down jackets about three feet thick.

"Is thinking is better use submersible from ship during summer than dive in late November," purrs Natalia.  Semilitov is wearing a smirk, like a KGB thug in a Bond movie.  "Is agree," he says.

Is bummer, I think.  I came a long way for nothing.

"Is local  bar and lounge where can find Stoli on rocks?" I ask, unzipping the wetsuit to reveal my down-lined tuxedo.

"Is of course," says Natasha. "Is Russia."  I love the way she says "Russia."  Like a native.

After a couple of Stolis, Natasha tells me that American climate scientists hate this methane angle. "Is messing up neat models," she says.  "Is, how you say, wild card.  Better to worry about 2100 than say a few weeks from now."

Is spot on, I'm thinking.  Semilitov is showing no signs of leaving, so I do.  They casually mention that maybe I'd like to come along on the Arctic cruise next summer.

"Maybe take the dive in submersible," she says coyly.  "Is room only for two."

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