Flammable ice may sound like an oxymoron, but it correctly describes the two faces of methane hydrate. An enticing source of frozen clean energy, it also poses a serious threat to the planet.
Methane burns cleaner than petrol, but before burning it is a potent greenhouse gas that requires extreme caution when handling. Last May, Chinese and Japanese geologists successfully extracted methane hydrate, an ice-like substance, from the South China Sea. Previous attempts to harness the gas trapped in the solid H20 molecules had failed; it would escape before it ever reached the surface. The recent breakthrough has sparked renewed interest in methane, an abundant fossil fuel whose appeal lies in its density: 1 m3 of methane hydrate contains 160 m3of gas.
Meanwhile, a team from Norway’s Centre for Arctic Gas Hydrate, Environment and Climate (CAGE) at the University of Tromsö has been studying craters up to 1 km deep on the Barents Sea floor. Bubbles continue to make their way to the surface, hinting at the powerful plumes of methane rising from the craters below. With the melting of the ice sheet 12,000 years ago, carbon deposits beneath the sea floor were suddenly under significantly less pressure. As a result, methane hydrate trapped in the deposits began to form mounds, which eventually erupted, leaving the craters we see today.
Similar explosions may be on the horizon. According to CAGE’s Alun Hubbard, “In Greenland and the Antarctic, the ice caps are melting fast. We know that there are large stores of gas hydrates hiding beneath those layers of ice. The sudden release of that methane into the atmosphere could in turn accelerate climate change, creating a phenomenon of mutual reinforcement”. In the Arctic, Norwegian researchers have detected methane domes 500 metres across; the area could eventually go the way of the Yamal Peninsula, where smaller holes in the permafrost have burst open.