Proponents of the so-called “methane time bomb” theory note the crumbling of glaciers in past eras destabilized methane hydrates, creating “blowouts.” As ice sheets dwindle, they lessen the pressure on gases bubbling below sediments enough that the gases can suddenly push sediment upward with a boom of force, resulting in heavy venting.Ī June 2017 study by the Center for Arctic, Gas Hydrate, Environment and Climate (CAGE) concluded those unexpected methane blasts, rather than gradual releases, are a big problem. ![]() Other experts, though, say thinning ice sheets on land and calving ice shelves on the sea are reasons for alarm. Even then, releases would be “slow and gradual.” Dlugokencky, in an e-mail, wrote there have been “no significant increases in Arctic emissions over the past few decades” and that it would take “centuries” for warming to affect methane hydrate–bearing sediments. In the shallower Arctic Ocean most of those deposits are tucked underneath a thick layer of sediment, impeding their travel. Most methane hydrates are buried in ocean water so deep that the journey through the water column is too far for the gas to ever reach the atmosphere, according to Ed Dlugokencky, a researcher at the National Oceanic and Atmospheric Administration. The situation, however, could change as ever-warming waters soften permafrost below, releasing methane, which in the atmosphere enhances warming further, creating a positive feedback loop. The study observed active methane plumes rising from the seabed, but most of the gas was not from hydrates and much of it did not reach the atmosphere. Even where methane increases are observed at the ocean surface, scientists need better data to determine whether emissions come from hydrates or other seafloor sources.Ī 2009 study of the West Spitsbergen continental margin north of Norway in the Arctic Ocean, led by University of Birmingham geophysicist Graham Westbrook, put into perspective the challenges the scientific community faces. But it is an open question whether the methane molecules released can rise through the water column into the air. Some of the methane hydrates in the Arctic and upper continental slopes such as the northern Pacific Ocean are beginning to thaw as temperatures rise. Those intertwined realities bring several hot-button issues to the fore: ![]() ![]() Credit: Wussel 007 Wikimedia (CC BY-SA 3.0)Īs countries produce more conventional and unconventional fuels, the planet is warming in areas where methane hydrates exist. Structure of a hydrate block embedded in the sediment of hydrate ridge. The remaining 1 percent occur in polar latitudes, mostly in permafrost soils onshore and beneath the Arctic Ocean. Nearly 99 percent of them outside Antarctica reside in sediments along continental slopes, more than 500 meters underwater in midlatitudes, 300 meters in higher latitudes. Most of the deposits, some small and some large, are buried in or below permafrost and sediments in the ocean bottom along continental margins-where shallow offshore waters slope down toward the deeper ocean floor. A cagelike structure of solidified water traps methane within it. Hydrates form when gas and water molecules fuse in low-temperature, high-pressure conditions. If fully developed, hydrates around the globe could provide as much energy worldwide as natural gas does today. Hydrates exist in the already commercialized Gulf of Mexico, too. The negotiations are considered “delicate,” says Tim Collett, a U.S. ![]() Production might still be a decade or more away in the U.S., which has been a quiet partner with Japan and China, although the Department of Energy has begun discussions with Alaska and Japanese interests about performing an extended production test in Alaska’s North Slope. The news caught natural resource experts off guard because most of them thought it would still be years before nations tried to turn these icy gases into commercial products. China soon followed with its first attempt to do the same. This issue has quickly risen because Japan conducted its second production test of these deposits, known as methane hydrates, in May. The answers seem to range widely, depending on who is talking. try to tap these abundant resources, important questions are arising about just how much they may contribute to climate change. As Japan, China and to a lesser extent the U.S. Turning big, frozen deposits of methane buried under the seafloor into fuel for our cars and homes is coming closer to reality.
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