Thursday, 11 December 2014

Methane Hydrates escaping from sea floor much faster than expected

A study of the sea floor off the West Coast of the United States has revealed that methane is escaping at 500 times its average rate of natural release.

Waters off the coast of Washington are gradually warming at a depth of 500 meters, which is the same depth at which methane transforms from a solid into a gas, helping to facilitate the release of the most powerful of greenhouse gases which can trap heat in our atmospheres 20 times better than carbon dioxide.

Methane, is continually released by the ocean from natural seafloor vents or in a simple cycle of freezing and melting, as part of the Earth's greater carbon cycle, but recently experts have expressed concern that methane (CH4) is seeing more release than ocean carbon sinks can make up for. This may be due to uncharacteristic warming of the sea as a result of climate change. This warming could be melting areas of frozen water on the ocean floor, collapsing pockets of gas called "methane hydrates, or clathrates" and causing it to be released at a much faster rate.

"If even a small fraction of Arctic sea floor carbon is released to the atmosphere, we're f'd," Jason Box, a widely published climatologist, tweeted back in August, when it was first revealed that this could be occurring in the East Siberian Arctic Ocean.

Many experts believe that these releases have the potential to speed up climate change well beyond
standard projections.

"Methane hydrates are a very large and fragile reservoir of carbon that can be released if temperatures change," Evan Solomon, co-author of the GRL study, explained in a recent statement. "I was skeptical at first, but when we looked at the amounts, it's significant."

It is estimated that four million metric tons of methane have been released since the 1970s. That's more than 40 times the carbon equivalent of all the methane released in the 2010 Deepwater Horizon disaster.

Researchers are shocked by these results, because the great majority of these methane releases were
expected to occur in the Arctic. However, other recent studies have found that there are more than 500 active methane vents along the US East Coast as well, adding an extra 90 metric tons annually from the Atlantic Ocean.

Scientists aren't sure how much of the methane hydates end up in the atmosphere. Much of it could be consumed by bacteria in the sediments below the seafloor or in the sea itself.  However, a consequence of this, that we already starting to see, is increased ocean acidification.

No comments:

Post a comment