The Arctic seafloor might have a larger methane time-bomb than previously assumed.

A new study has found that the East Siberian Arctic Shelf is releasing 17 teragrams of methane each year, about twice as much as previous estimates. One teragram is about 1 million tons. What’s worse is that climate change might be accelerating its release.

The study was conducted by researchers at the University of Alaska, Fairbanks and colleagues.

Methane is the second-most prevalent greenhouse gas in the environment, according to Environmental Protection Agency. Although methane’s lifespan (about 10 years) in the environment is shorter than carbon dioxide, it traps more heat.

In the seabed, the greenhouse gas is stored as methane hydrates. The arctic permafrost acts like a cap, preventing methane from escaping into the atmosphere. Increasing temperatures are now thawing these caps, allowing the gas to escape.

The East Siberian Arctic Shelf is three times larger than the nearby Siberian wetlands, which was once considered to be a primary source of methane. Previous research had suggested that ESAS was releasing about 8 teragrams of the gas annually.

‘It is now on par with the methane being released from the arctic tundra, which is considered to be one of the major sources […]