Greenhouse emissions could skyrocket if methane escapes frozen prison

Greenhouse gas emissions could skyrocket if the permafrost on an Arctic island melts, scientists have found.

Millions of cubic meters of methane are trapped under the permafrost on Svalbard island in Norway. Permafrost is a permanently frozen layer underneath the surface of the Earth. And in this case, it serves as a frozen prison for this catastrophic amount of methane.

But the permafrost is rapidly melting due to the warming climate. This means that vast amounts of methane could escape into the atmosphere, according to a new study published in Frontiers in Earth Science.

“At present the leakage from below permafrost is very low, but factors such as glacial retreat and permafrost thawing may ‘lift the lid’ on this in the future,” Thomas Birchall of the University Center in Svalbard, and lead author of the study said in a press release on the findings.

Methane is a potent greenhouse gas emitted into the atmosphere from both human activities and natural processes. It is the second most significant contributor to climate change after carbon dioxide.

Svalbard is very similar to the rest of the Arctic in terms of its geological and glacial history, according to the study. This means vast amounts of methane may be present elsewhere in the region.

To study the permafrost, researchers used historical data to map the frost and the accumulation of methane beneath it. However, it remains a complicated topic of study due to its being extremely inaccessible to humans.

But it is possible to measure using wellbore—holes drilled in the ground to retrieve resources such as oil and gas.

Svalbard has widespread permafrost; however, it is patchier in certain areas. Ocean currents towards the island’s west mean it is warmer there, making the permafrost elsewhere thinner with more patches. Therefore, an escape of methane would be more likely here, as the permafrost is more likely to melt, releasing the potent gas.

But even in areas where the permafrost is thick—such as in the island’s lowlands—there is potential for the gas to escape.

Scientists looked out for ice forming inside the wellbore, as well as changes in background gas measurements. They discovered abnormal amounts of pressure beneath the permafrost, which suggested it acted as a seal for the gas below.

“All the wells that encountered gas accumulations did so by coincidence—by contrast, hydrocarbon exploration wells that specifically target accumulations in more typical settings had a success rate far below 50%,” said Birchall. “These things seem to be common. One anecdotal example is from a wellbore that was drilled recently near the airport in Longyearbyen.

“The drillers heard a bubbling sound coming from the well, so we decided to have a look, armed with rudimentary alarms designed for detecting explosive levels of methane—which were immediately triggered when we held them over the wellbore.”

Previous research has shown that the upper layer of permafrost around the world is thawing at a quicker rate with the warming climate. The question as to whether or how the deeper layer of permafrost is affected remains a mystery and very difficult to study.

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