This image shows a chunk of burning methane hydrate. The inset image shows the hydrate's molecular structure: A lattice of water ice that traps the methane inside.
Courtesy U.S. Geological Survey Methane reserves deep in the ocean and in arctic permafrost might trigger runaway global warming. But they've also got the potential to provide huge amounts of power, a possibility that is attracting the interest of energy companies.
Methane hydrate, a strange form of natural gas, has recently become a fascination for energy-hungry nations from the United States to Japan and India. Hydrate is found in oceans across the world, where the gas is trapped in icy structures below the seabed, and also lies beneath the Arctic's permafrost.
A paper published this week in Nature suggests that the release of methane hydrates, also known as clathrates, may have triggered a very rapid period of global warming 635 million years ago -- and may do so again. But those same hydrates are also a tempting target for energy production.
"What we've been asked to do is to make this a viable option for the policy makers in the future, and to figure out what's available to us," says Ray Boswell, a researcher with the U.S. Department of Energy's methane hydrates R&D program. "You don't want to find out that you need it, and then find out that you're 30 years down the science and technology curve."
The Gulf of Mexico is estimated to hold more than 6,500 trillion cubic feet of hydrate in sandstone reservoirs, currently the best candidates for commercial exploitation, according to the U.S. Minerals Management Service. If only 5 percent of that hydrate could be tapped, it would yield more than 300 trillion cubic feet of gas. By comparison, the United States' reserve of conventional natural gas is currently estimated at 211 trillion cubic feet.
Researchers romantically call methane hydrates "the fire in the ice," since the frosty chunks burn if you set a match to them. But it's not just romance that's drawing energy companies to the frozen fuel. While methane hydrates have previously been too expensive to extract on a commercial scale, the increasing price of oil -- now more than $130 per barrel -- means the hydrates might soon become a profitable energy source. Chevron has been involved in the gulf research, and BP is exploring for hydrates in Alaska. Japanese engineers reportedly pumped hydrates from a test well in Canada's Northwest Territories this last winter.
"Everybody knows there's a lot of it," Boswell says. "Now, our goal is to understand the ramifications: Does it have potential as an energy resource, and if so, how would you go about getting it? And how does it fit into climate issues?"
It's that last question that opens up the can of worms. Even as some researchers wonder whether methane hydrate could play an important role in powering the 21st century, others ask whether it has played a critical part in catastrophic climate shifts in the past -- and if it could do so again.
The troubling questions arise from prehistoric climate blips that researchers are still struggling to understand.
The most recent abrupt climate change occurred 55 million years ago during the Eocene greenhouse event, when ice disappeared from the poles and trees grew in Antarctica. From analyzing the fossil record, researchers determined that there were very high levels of methane in the atmosphere at that time.
Some paleoclimate researchers hypothesize that a gradually warming climate brought oceans to a temperature tipping point around 55 million years ago, which caused icy methane hydrate structures to melt and let the gas bubble up to the ocean's surface in a long, enormous burp. Since methane is a more powerful greenhouse gas than carbon dioxide, if it were released into the atmosphere in a huge gush, it may have caused temperatures to spike dramatically.
This theoretical precedent has led to speculation in popular science books that our current bout of man-made global warming could cause another catastrophic methane release. But the dominant scientific paradigm is that methane is more likely to be an issue over the long term.
David Archer is an ocean chemist at the University of Chicago who called methane the "crouching tiger of the carbon cycle" on a respected climate blog.
"It's predicted that with a doubled [carbon dioxide] concentration, the deep ocean could eventually change its temperature by about three degrees," Archer told Wired.com. "Three degrees would eventually get rid of all the methane in the ocean. But at what rate -- that's the question."
After conducting his most recent modeling experiments, Archer says that methane released from the ocean could accelerate global warming over a time frame of thousands of years. But we don't have a serious cause for alarm within our lifetime, he says. Smaller releases of methane hydrate are likely as the Arctic permafrost thaws during this century, "but those are equivalent to a volcano eruption," Archer says. "It's not a doomsday thing."
But the lead author of the new Nature paper, Martin Kennedy of the University of California at Riverside, explicitly called a release of methane hydrate "a doomsday scenario for the climate," and called for far more research into methane's role in the world's climate.
While U.S. scientists are proceeding fairly slowly, investigating both the risks and benefits of methane hydrates, other countries are on a faster track.
Japan, South Korea, China and India are all determined to make methane hydrates a viable energy source. India spent $35 million on a 2006 expedition to explore deposits along its coasts, while South Korea, which currently relies on imported natural gas to fuel most of its power plants, has pledged to start commercial production by 2015.
The world may have found a successor to the gold rush and the oil boom: the methane bubble.
Wired Science: Could Methane Trigger a Climate Doomsday Within a Human Lifespan?
