Schiel was unfazed. He took a seat halfway down the long table, next to me, across from Hilda, looking around the room with interest. “Possible?” he repeated ruminatively. “Yes, in principle, Mr. Pell. Methane is a very common compound. It’s the first member of the alkane hydrocarbons, a very simple molecule, and there’s a great deal of it around in the form of clathrates, at least ten to the fifteenth cubic meters-Pardon? Oh.” He moved his lips for a moment, doing arithmetic. “At least ten thousand million million cubic meters of the stuff, that is. Probably more. Much of it’s locked up in permafrost in Asia and North America, but there’s a tremendous amount on the sea bottoms. If you’d care to look-I asked my staff to transmit a map of the main deposits to me on the plane-“
He did something to the control for the screens at each place. While we were looking at them he investigated the coffee jug at his place, found it was full, poured himself a cup and waited for us to see what he was talking about.
I swallowed when I saw where the main deposits were: some of the biggest along the Atlantic Coast of the Americas, along the Pacific shore of Panama, the Bering Strait-I knew those areas well. “That’s exactly where the subs are concentrating,” I said.
Pell gave me a shut-up look; he had obviously figured that out for himself. “How come you know all this?” he demanded, looking at Schiel.
Schiel put down his coffee cup. “Why, the methane beds have been investigated quite thoroughly; there was some hope of tapping them as a replacement for petroleum resources. Methane is a very good, clean-burning fuel, but some of the best deposits are a kilometer deep or more, and they’re not easy to exploit. Perhaps I should explain their physical nature?”
Pell sighed, reconciling himself to being lectured at by an expert but seeing no way out of it. “Perhaps you goddam should,” he grumbled.
Schiel nodded briskly and went on. “The methane content of the clathrates is hydrated,” he said. “That means that each methane molecule is surrounded by a sort of cage of water molecules, in the form of ice under pressure. If the temperature rises or the pressure decreases, the clathrate disintegrates. When samples are trawled up from the sea bottom they begin to bubble and sizzle and fall apart even before they reach the surface, often quite explosively. Worse, there is some evidence that any attempt to exploit these resources for fuel may be quite dangerous. You see, under the clathrate beds there are trapped bodies of gaseous methane. When the crust is broken through, the methane gas can escape. In great volume, Mr. Pell. In which case it appears capable of turning the ocean itself into a sort of froth which is no longer dense enough to float a vessel. A Soviet drilling ship which was mysteriously lost many years ago is thought to have sunk when that happened, and there have been conjectures that such events, off the coast of the Carolinas, may have been responsible for some of the alleged disappearances in the so-called Bermuda Triangle.” He looked around the room. “Is that what you wanted to know, Mr. Pell?”
The deputy director was frowning at the map. He stabbed at the Carolina coast. “Those submarines,” he said. “Could they be used to blow a hole in this clathrate cap thing?”
Schiel shrugged. “I know nothing of the Scarecrow submarines,” he said, “but if they could plant some very large mines, yes, I think so. That might not be necessary, though. If they simply disturbed the clathrates sufficiently, they could start a release, which might then sufficiently lower the pressure to cause a greater release, entraining more and more clathrates as they rise to the surface. Once started, it could be a runaway effect, increasing exponentially as long as the methane held out.”
Pell thought that over. “That would be a pain in the ass,” he said at last, “but it doesn’t sound fatal. All right, they can turn some coastal waters into club soda for a while. We might lose some shipping, but so what? It wouldn’t destroy the world.”
“Oh, Mr. Pell,” Schiel said forgivingly, “but it quite well might. Once a large-scale release began-Well, similar events have already happened here on Earth, you know. For example, it is believed that one such might have ended the Ice Age.”
The deputy director blinked at him. “What?”
Schiel nodded. “That was twenty-two thousand years ago,” he said. “Geologists have determined that there was a huge landslip in the western Mediterranean at that time. That was when the Ice Age was in full force; worldwide ocean levels were the lowest ever, the amount of ice the highest. This caused some sea bottom to be exposed in the Mediterranean basin around Sardinia. There were deposits of icy methane-containing hydrates there, as there are in many shallow seas. When the sea level dropped, the pressure on them fell, as I discussed. They began to release their methane; the methane lubricated the slide; the slide released more methane-we think about half a billion tons al-together, nearly doubling the amount of methane in the atmosphere at the time. And the world warmed up and the Ice Age ended. Methane is dangerous stuff, you see. And that was just one local release. Actually,” he said, sounding almost pleased to be able to tell us about it, “there is some evidence that one of the great extinctions of the geologic past took place as the result of a larger event. It was when all the present continents were joined together in one great land mass, called Gondwanaland-“
“Screw Gondwanaland,” Pell snarled. “What happened?”
“Why, as you may know, methane is a very powerful greenhouse gas. There would have been wide-scale warming-“
“Warming?” Pell looked almost reassured. “We could stand some warming, couldn’t we?”
But Schiel was shaking his head. “We wouldn’t live long enough to see it. I don’t think I’ve made clear just how much methane we’re talking about, Mr. Pell. Released, it could form a layer of gas thirty meters deep, covering the entire world. Because it is denser than either oxygen or nitrogen, it would tend to concentrate near the surface. We can’t breathe methane.”
Pell’s expression was icy now. “And the Scarecrow subs could make this happen?”
Schiel looked stubborn. “Given the application of enough heat or physical intervention on a wide enough scale, given the likelihood that it could become a self-sustaining reaction-“
“Yes or no, damn it!”
“Well, yes,” the scientist said.
The word hung there for a while.
Then the deputy director stirred himself. “Will you excuse us for a moment, Mr. Schiel? If you’ll just wait outside ...”
He drummed his finger until the scientist was gone, taking his coffee with him. “All right,” he said then. “What are our options? Hilda?”
