An expedition to the East Siberian Sea has reported two examples of what scientists have long feared – methane fountains bubbling to the surface as frozen material on the ocean floor melts after an unusually warm summer. So far the affected areas are too small to have much global impact, but may be the harbinger of worse things to come.
Methane is an even more potent global warming gas than carbon dioxide – its impact is 80 times greater than CO2 over 20 years years and 34 times greater over a century. Vast quantities of it are locked up in the Arctic, both beneath the oceans and in Siberian permafrost. As human activity warms the world, some will be released, causing further warming. The big question, perhaps the planet’s biggest, is how much?
Famously, on finding some methane bubbling to the surface of the sea in 2014, Professor Jason Box summarised the situation as: “If even a small fraction of Arctic sea floor carbon is released to the atmosphere, we're fucked.”
Igor Semiletov, of Russia’s Tomsk Polytechnic University, is currently leading a team of more than 70 scientists to East Siberia to assess the danger. While collecting seawater and sediment samples off Bennett Island, a statement (in Russian) from the University reports he and his team detected methane levels six to seven times higher than normal.
According to the statement, the team noticed a lighter colored area of water around 4-5 square meters (40-50 square feet) nearby that on approach they saw was “boiling with methane bubbles”. Above the fountain atmospheric methane was nine times the global average. Instead of using special plastic cones designed for sampling methane-rich waters the bubbles were so frequent the team was able to simply scoop it up in buckets and pump some of it into cylinders as compressed gas. A second, similar fountain was observed the following day.
“This is the most powerful gas fountain I've ever seen. No one has ever recorded anything like this before,” Semiletov said, reports The Moscow Times.
Of all the potential tipping points where a modest warming could trigger something far worse, the “Clathrate Gun”, where Arctic methane boils dramatically, is possibly the worst, and certainly the most famous. It is thought to have been the cause of the relatively sudden warming known as the Paleocene-Eocene Thermal Maximum million years ago. It may not quite be the boiling seas predicted (depending on translation) by the Book of Revelations or the Qur'an, but it could still be an apocalypse.
However, it is unclear how great the danger really is. Methane frozen in deep waters is usually consumed by microbes before it can reach the surface to do any harm. Currently, the Arctic Ocean accounts for less than one ten-thousandth of methane emissions, so even a hundred-fold increase would be barely noticeable. Land-based Arctic permafrost is currently a much bigger source.
Moreover, it is possible methane fountains have always been a feature of the Arctic Ocean, caused by local phenomena. Having studied the area so poorly until recently we lack a good baseline to know what is normal.