The Arctic is warming faster than any other region on Earth, and this has serious implications for the global climate. One of the most alarming consequences is the potential release of large amounts of methane, a powerful greenhouse gas, from the frozen ground.
Methane is formed by the decomposition of organic matter in the absence of oxygen. It can be trapped in the soil or in ice structures called hydrates. When the temperature rises, the methane can escape to the atmosphere, where it contributes to the greenhouse effect and further warming.
Scientists have long been aware of the risk of methane emissions from the Arctic permafrost, but a new study has revealed a surprising and worrying phenomenon: natural gas is actually migrating under the permafrost, and could see methane emissions skyrocket if it escapes.
The study, published in Frontiers in Earth Science¹, was conducted by researchers from the University Center in Svalbard, Norway. They used historical data from commercial and research wellbores to map the permafrost across Svalbard, an archipelago in the Arctic Ocean, and identify permafrost gas accumulations.
They found that millions of cubic meters of natural gas, mostly methane, are trapped beneath the permafrost, and that some of it can migrate laterally under the cold seal of the permafrost and escape through cracks or faults.
The researchers explained that this phenomenon is related to the geological and glacial history of Svalbard, which is very similar to the rest of the Arctic region. The natural gas originates from the rocks below, which are often fossil fuel sources. The gas accumulates at the base of the permafrost, where the temperature and pressure are favorable for its stability.
However, the permafrost is not uniform or continuous. It varies in thickness, composition, and permeability depending on the location and the climate. In some areas, the permafrost is thin, patchy, or ice-poor, which allows the gas to migrate and seep through. In other areas, the permafrost is thick, continuous, or ice-rich, which acts as an effective seal to the gas.
The researchers warned that the migration and leakage of natural gas under the permafrost could increase in the future, as the Arctic warms and the permafrost thaws. This could create a positive feedback loop, where more methane emissions lead to more warming, which leads to more permafrost degradation and more gas release.
"Methane is a potent greenhouse gas," said Dr. Thomas Birchall, the lead author of the study. "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."
The study highlights the need for more research and monitoring of the permafrost gas accumulations, as well as the potential impacts of their release on the climate and the environment. The researchers also suggested that the natural gas could be exploited as a source of energy, if it can be extracted safely and sustainably.
The Arctic is a region of immense beauty and importance, but also of great vulnerability and uncertainty. The discovery of natural gas migration under the permafrost adds another layer of complexity and challenge to the management and conservation of this fragile ecosystem.
