LANL model checks arctic warming

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Bacteria may slow release

By Roger Snodgrass

A Los Alamos National Laboratory researcher is challenging theories about one of the most worrisome possibilities arising from global warming in the arctic.

For the last few years, climate researchers have debated the potential risks of a massive release of huge methane reservoirs currently trapped at the bottom of the arctic seas.

The methane is caged in ice lattices, or clathrates, which are thought to be particularly vulnerable to release in the rapidly warming waters of the arctic. Some climatologists blame runaway events like the Great Dying, 250 million years ago, the worst extinction event in Earth’s history, on the sudden release of methane clathrates buried under the cold ocean floors.

“The possibility that methane will be emitted from marine clathrates has been under discussion for several decades,” said Scott Elliott, a member of the ocean modeling program at LANL. “It’s been a political and scientific football for a long time.”

The concern is that vast amounts of what are now stabilized little packages of methane might suddenly start floating toward the surface burping what is considered to be a very powerful greenhouse gas into the atmosphere.

The Pew Environment Group released a report Friday that quantifies the global cost of the Arctic’s declining ability to cool the climate, indicating that the rapid melting of the region could carry a minimum price tag of $2.4 trillion by 2050.

Methane, according to the Environmental Protection Agency is 20 times more effective than carbon at trapping heat and persists in the atmosphere for 9-15 years. A worst-case nightmare imagines global warming beginning to take off, dislodging the clathrates and causing a convulsion of hyper-accelerated global warming.

Elliott uses a supercomputer for sea ice modeling at Los Alamos National Laboratory as a member of the team that participates in the Intergovernmental Panel on

Climate Change.

At the American Geological Union in December and at a Department of Energy conference on methane clathrates at Georgia Tech in January, he presented some new results from the lab’s computer models proposing possibilities that might limit the dangers.

For one thing, Elliott’s models include methanotrophs, methane-eating bacteria that could intercept the methane.

“We asked how far the methane could go and could the bacteria in the ocean eat it before it got to the atmosphere,” he said.

“We run the methane up into seawater and where plumes of methane are formed,” he said in an interview Friday. “The math is the same as for a pollution plume into the atmosphere, like a forest fire.”

In part, the result depends on how much oxygen there is and other supplemental nutrients the bacteria need.

“In some places, they might run out,” Elliott said, noting another layer of security that might protect the system. The rivers that help form the continental shelf are constantly bringing fresh, less salty water, “that forms a cap that prevents the methane from getting all the way to the atmosphere,” he said.

So far, the question is far short of an answer because of the complexity of the system.

 “It is possible that the circulation of the Arctic Ocean may change,” Elliott said. “We already know the sea ice is going away and the wind system is changing. The fresh surface layer may become more or less stable. I wouldn’t even be able to guess which way that would go.”

Another complicating factor is that the molecular capsules, also known as methane hydrates intrigue energy companies, as well, as a possible source of energy.

“There are convincing arguments that vast amounts of methane gas hydrate are present in sediments under the world’s oceans as well as in on-shore sediments in the Arctic,” according to a Stanford University study. “This hydrate is possibly the largest carbon and methane pool on earth.”

Although currently extremely difficult to mine as an energy source, the jury is still out on what kind of role methane clathrates will play in the planet’s future.