Leaking ‘fire ice’ is new threat to the planet
It sounds like something from Game of Thrones. But the threat is not coming from Westeros, rather from beneath the ice sheets of Antarctica.
Fire ice — a marshmallow-like ice formation stored in vast quantities below the sea bed — is leaking huge plumes of gas which could accelerate climate change or trigger tsunamis, scientists fear.
The substance, known by scientists as methane hydrate, is nicknamed “fire ice” because when brought to the surface chunks of the frozen material can be set alight. That is because it holds methane, or natural gas, one of the most potent greenhouse gases on the planet with a global warming potential 30 times greater than carbon dioxide.
Previously unknown methane emissions coming from a store of fire ice have now been detected by a team of Spanish scientists. Led by the geologists Ricardo León and Roger Urgeles, the team last month discovered several large methane plumes erupting from the sea floor during an expedition to Antarctica. While methane plumes were already known to exist in the Arctic and the Black Sea, this was the first time they had been detected in Antarctica, the researchers said.
The emissions reach peaks of 350m in height, 700m in length and 70m in width, with the largest plume originating at a depth of about 750m metres below sea level. These emissions, if they are reaching the atmosphere, are not accounted for in current climate models.
León, of Madrid’s Geological and Mining Institute, said: “[These emissions] represent a new variable which, given its magnitude, should be taken into account when making climate projections or designing future climate scenarios. It is really important.”
The methane hydrate resembles the texture of a marshmallow
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The Antarctica flares fizzle out at about 150m metres below sea level and further tests are required to gauge how much methane — if at all — they are releasing into the atmosphere. There is still a hope that they could be dissolved into seawater before they reach the surface.
The Antarctica expedition was the culmination of a four-year research process. The team set out from Punta Arenas, Chile, on expedition vessel Sarmiento de Gamboa which is owned by the Spanish National Research Council, on January 13. They found that the melting of the Antarctic ice sheet was indirectly causing methane to seep through fault lines along the ocean floor.
This is known to happen when fire ice becomes unstable due to varying temperature and pressure at the bottom of the sea.
The scientists identified methane plumes coming from reserves of fire ice
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When unstable, fire ice breaks down into its main components — water and gaseous methane. Gaseous methane eventually bubbles up through the sea floor, sometimes in the form of methane plumes.
This is part of a larger phenomenon known as isostatic rebound, which is brought on by the melting of the ice caps and consequent rise of land masses.
Fire ice, the geologists estimated, can be found at high concentrations in the marine subsoil of an area spanning at least 5,000 square kilometres around King George Island and Elephant Island in Antarctica.
The team are monitoring the fire ice over fears about its implication for climate change
Urgeles, of Barcelona’s Institute of Marine Sciences, insisted that all findings so far were “preliminary” and it was as yet unknown whether climate change had in any way prompted the phenomenon or contributed to it.
“I want to stress that we do not yet know whether this process is in any way linked to man-made climate change or not,” he said. “We do not know if it is natural.
“We know an isostatic rebound is taking place. It is largely due to the loss of ice suffered by the caps during the last glacial maximum and it may have been sped up recently by man-made climate change. But as of right now I cannot say whether these methane plumes are related to climate change at all.”
The study was funded by the Spanish Ministry of Science, Innovation and Universities as part of the “Ice Flame” project. The geologists stressed that further analysis of the sediment and water samples they collected on their voyage, as well as several other tests, was needed before they could draw any definitive conclusions.
The team worked off the tip of the Antarctic Peninsula
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The geologists also warned of a further, long-term risk. As fire ice breaks down into water and free methane, the latter expands to a volume 160 times greater than its solid form and is liable to displace large amounts of soil, causing huge landslides and even tsunamis in the process.
The largest known underwater landslide in history — the Storegga landslide — is thought to have been caused some 8,150 years ago by methane hydrates turning into gas.