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Methane, the principle component in natural gas, is usually produced by organic material decomposing.

But there is another form of the deadly gas, dubbed abiotic methane, that is created by chemical reactions in the crust beneath the seafloor.

Now scientists have found vast deep water gas hydrates in the Arctic that are reservoirs for abiotic methane – a gas which is 20 times more effective in trapping heat than carbon dioxide.

The gas forms through a process called serpentinisation. Serpentinisation occurs when seawater reacts with hot mantle rocks exhumed along large faults within the seafloor 

The reservoirs are secure, and scientists don't believe they will impact climate change. Instead, they say similar formations could someday be used to store methane, that can later be used as fuel.

One reservoir was recently discovered on the ultraslow spreading Knipovich ridge, in the deep Fram Strait of the Arctic Ocean.

'This ultraslow spreading ridge shows that the Arctic environment is ideal for this type of methane production,' said Joel Johnson associate professor at the University of New Hampshire.

The Center for Arctic Gas Hydrate, Climate and Environment (Cage) estimates that up to 15,000 gigatonnes of carbon may be stored in the form of hydrates in the ocean floor.

Scientists have found vast deep water gas hydrates in the Arctic that are reservoirs for abiotic methane – a gas which is 20 times more effective in trapping heat than carbon dioxide. One such reservoir was recently discovered on the ultraslow spreading Knipovich ridge (pictured), in the deep Fram Strait of the Arctic Ocean.

'But this estimate is not accounting for abiotic methane. So there is probably much more,' said Cage director Jürgen Mienert.

They believe the gas forms through a process called serpentinisation.

'Serpentinisation occurs when seawater reacts with hot mantle rocks exhumed along large faults within the seafloor,' said Johnson.

'These only form in slow to ultraslow spreading seafloor crust. The optimal temperature range for serpentinisation of ocean crust is 200 – 350 degrees Celsius.'

Methane produced by serpentinisation can escape through cracks and faults, and end up at the ocean floor, causing a concern for future global warming.

But in the Knipovich Ridge it is trapped as gas hydrate in the sediments.

'In other known settings the abiotic methane escapes into the ocean, where it potentially influences ocean chemistry,' says Johnson.

'But if the pressure is high enough, and the subsea floor temperature is cold enough, the gas gets trapped in a hydrate structure below the sea floor.'

Bünz says that there are many places in the Arctic Ocean with a similar tectonic setting as the Knipovich ridge.

Rather than causing a concern, the study claims that active tectonic environments may serve as a stable area for long-term storage of methane carbon in deep-marine sediments.

But other types of methane in the Arctic are causing a concern for scientists. 

Last year Dr Jason Box who claims that methane will be the main driver of climate change if it escapes into the atmosphere.

He tweeted: 'If even a small fraction of Arctic sea floor carbon is released to the atmosphere, we're f'd'

The scientist, based at the Geological Survey of Denmark and Greenland, tweeted the provocative statement after a Swedish study found methane leaking beneath the Arctic.

Some of this methane – which is over 20 times more potent than CO2 at trapping heat - is now making it to the ocean's surface.

Scientists at Stockholm University called the discovery 'somewhat of a surprise,' which, according to Dr Box, is an understatement.

Samples of the gas hydrates will provide more knowledge on abiotic methane. But they need to be drilled, as they are 140 metres under the ocean floor