As the reinsurance and risk industry gathered in Monaco this week to discuss the ever more complex and interconnected nature of the world’s risks, scientists announced the planet may well have been plunged into a methane “doom loop”.

Reinsurers were expressing their determination to play a part in supporting global businesses to meet the threats they face, and the annual reinsurance rendezvous was used as a rallying call for action for an industry which is heavy with capital, capacity and profits.

However, as the call went out a new study raised concerns about a climate feedback loop as melting Arctic glaciers flush ancient methane from rocks beneath the ice

Meltwater rivers flowing from Svalbard glaciers are carrying ancient methane from rocks beneath the ice into the open air, the researchers warned

The findings revealed a natural feedback loop that may worsen as the Arctic continues to get warmer. Melting glaciers can open hidden pathways for methane, a powerful greenhouse gas. Put simply, the more glaciers melt, the more methane they are likely to release.

The study led by Gabrielle Kleber, a researcher with the iC3 Polar Research Hub in Tromsø, Norway, took 148 water samples from 19 glacier-fed rivers in central Svalbard, providing by far the most extensive assessment yet of methane in glacier meltwater in the region. Every river in their survey contained more methane than expected from contact with the atmosphere, with the highest values reaching up to 425 times that level.

Co-author Silje Waaler said the team deliberately designed the survey to capture the diversity of glaciers across the region.

“We wanted to study many different glaciers, across a range of rock types and ice conditions. That gave us a clearer picture of why some glacier rivers carry more methane than others,” she explained.

A key finding is that this methane is mostly not being made by microbes under the ice, as has been observed beneath glaciers in Greenland.  Instead, it appears to come from Svalbard’s geology. Many parts of the archipelago contain old shale layers rich in organic carbon. Over millions of years, heat and pressure can turn this material into methane and other gases.

“These glaciers are mostly melting on their surfaces,” Kleber added. “But this meltwater finds its way to the bottom of the glaciers through crevasses and holes. This means that it interacts with the rocks underneath, and where those rocks contain ancient gas, the water can flush methane out into rivers.”

The researchers estimate that land-terminating glaciers across Svalbard may transport roughly 182 to 368 tonnes of methane per year in meltwater, depending on how the estimate is scaled. This is in addition to previous, much higher estimates for methane released by groundwater springs in front of glaciers. But it still points to a widespread and undercounted pathway for ancient carbon to reach the atmosphere.

Kleber concluded: “The amounts reported here are small compared with human-caused emissions from fossil fuels, farming and waste. But they matter because they reveal a natural feedback loop that is not confined to Svalbard, and that may grow as the Arctic warms.”

(Re)insurers want to  get proactive on resilience and it looks likely the climate will present ever greater tests in the years to come.

Jon Guy, Editor

Emerging Risks