While the USGS has not yet calculated the total size of the potential methane hydrate reserve in the Gulf of Mexico, Collett and his colleagues have calculated the scale of another much more accessible reserve where they hope to perfect the technology required for long-term production of methane hydrates: Alaska's North Slope.

The North Slope is already home to a great deal of conventional oil and natural gas extraction (it's the northern terminus of the trans-Alaska pipeline), and it is, not coincidentally, just a few hundred miles west of Mallik.

The USGS used sophisticated three-dimensional modeling and assessment techniques to estimate the probable amount of recoverable gas from Alaska's North Slope: the median yield was calculated to be 85.4 trillion cubic feet, or four times as much natural gas as the United States uses in a year. The model was built using seismometers that peer into the earth like sonar, listening for the propagation of sound waves generated by a controlled source; recordings of that data can be turned into a complete picture of the size and shape of the hydrate reserves.

"This would be the single largest assessed volume of gas resources in the U.S.," says Collett, who cautions that his calculations reflect only what is technically producible from the field but don't take into account whether or not it will be economical to do so.

Mallik has taught scientists how to produce gas from methane hydrates, and the reservoirs in Alaska's North Slope and the Gulf of Mexico suggest that Mallik is not a unique case. The real challenge, however, will be figuring out how to extract sufficient gas economically. This depends on the proximity of the hydrates to existing pipelines and the price and availability of natural gas: no one will pay to develop new resources, after all, until the old ones have become sufficiently expensive.

To date, none of the world's extraction or assessment attempts have been primarily funded by industry. Companies that have participated in methane hydrate field research in North America include Chevron, ConocoPhilips, and BP.

"The question is, does the industry have the ability to stand on its own without government support?" says Collett. "At some point, they will be, and we think we're now nearing that breaking point."

The United States is not the only country with plans to attempt long-term production tests of methane hydrates. Japan is spending by far the most money on methane hydrate research; it provided most of the funding for the Mallik tests, which were sponsored by the Japan Oil, Gas and Metals National Corporation and by Natural Resources Canada, with field operations by Aurora College/Aurora Research Institute and support from Inuvialuit Oilfield Services.

According to the Center for Hydrate Research's Koh, Japan is investing heavily in attempts to harvest deep-sea hydrate reserves discovered off the southern coast of Japan in the Nankai Trough.

"The Japanese are planning commercial production from the Nankai Trough by 2017," says Koh. If they succeed, Japan will tap the first domestic fossil-fuel reserves the country has ever known.