Rodolfo del Valle and his team are heading to the Southern Ocean to measure a methane leak.

For three years, Rodolfo del Valle and his team will be probing the ice and seabed in the Erebus and Terror Gulf.

Ana Belluscio

Persistent bubbling is stirring the water’s surface in the Erebus and Terror Gulf, a remote spot off the Antarctic Peninsula. When he saw the commotion in 2000, Argentinian geologist Rodolfo del Valle was intrigued — despite 38 years’ experience in the region. There was a chance the gas contained methane, and when del Valle’s team investigated the leak they discovered it to be 99% methane.

This is bad news. The gas is not only 25 times more powerful than carbon dioxide at heating the atmosphere; methane hydrates locked up in the Antarctic seabed and ice also contain vast amounts of carbon — overall, methane deposits contain about half of global carbon. With a recorded decline in Antarctic ice shelves, the long-term effect of deteriorating and melting ice could range from boosting global warming to helping trigger mass extinctions. Nature caught up with del Valle on the eve of his departure for the first on-the-ground study to quantify methane leakage in shallow waters and ice in the Gulf.

What’s the overall rationale for your upcoming three-year focus on methane hydrate deposits?

Statistics and figures aside, I have been participating in Antarctic expeditions for so long that I’ve seen entire ice shelves crumble into pieces small enough to prepare a Scotch on the rocks. We have had to redraw maps. Global warming is a fact, and once we quantify methane emissions we will have scientific proof that the substrate on the seabed is melting and leaking methane. If these methane deposits reach the atmosphere, they will deepen the greenhouse effect, which, in turn, will promote further methane release, thus closing the circle and ramping up warming.

A number of studies have pointed to methane as a factor in mass extinctions. Are we looking at the start of a similar scenario now?

By quantifying the emissions and establishing their magnitude, we will be able to begin to determine how they will affect global warming. We believe there is a huge amount of destabilized methane deposits that may leak into the atmosphere and ramp up warming. This is not a new fact in geological history. Of seven major mass extinctions that erased 90% of the species at the time, five are attributable to climate change, and one in particular — at the Permo-Triassic boundary — could be directly attributable to mass methane release in the Upper Palaeozoic. Read more…

Source: Nature.com