It is assumed that the globally relevant amounts of methane in the Natural gas deposits underground and Arctic coal beds are sealed under a frozen cryospheric catchment of permafrost and glaciers.
But at sufficiently high pressures and temperatures, Methane under permafrost And glaciers can be trapped as a solid gas hydrate. These pressure and temperature conditions can change with climate warming and glacial retreat, potentially causing the disintegration of gas hydrates and the release of deep, underground methane into the Arctic atmosphere.
Now a new study, led by researchers from the University of Cambridge in the UK and the University Centre Svalbard in Norway, identified large methane gas reserves that escaped from the springs of groundwater revealed by the melting of the glaciers.
The new research, which has just been published in Nature Geoscience, suggests that these methane emissions will likely increase as Arctic glaciers retreat and more springs are exposed. This, and Other methane emissions from melting ice and frozen ground in the Arctic could exacerbate global warming.
“These springs are a considerable, and potentially growing, source of methane emissions, one that has been missing from our global methane budget estimates so far,” he reported. Gabrielle Kleber, lead author of the research, from the Department of Earth Sciences at Cambridge.
Kleber spent nearly three years monitoring the water chemistry of more than a hundred springs in Svalbard., where air temperatures are rising twice as fast as the Arctic average. “Since this is happening, we are in a position to preview the potential methane release that could occur on a larger scale in this region.”
Professor Andrew Hodson, co-author of the study from the University Centre Svalbard, said: “Living in Svalbard exposes you to the frontline of Arctic climate change. I can’t think of anything more raw than the sight of the Methane outgassing in the immediate field of view of a retreating glacier“.
“While the focus is often on permafrost, this new finding tells us that there is Other pathways for methane emissions that could be even more significant in the global methane budget,” said study co-author Professor Alexandra Turchyn, also from Cambridge’s Department of Earth Sciences.
Hodson added: “Until this work was carried out, we didn’t understand the source and escape routes because we were reading about studies of completely different parts of the Arctic where glaciers are absent.”
The methane delivery springs they identified are fed by a pipe system hidden beneath most glaciers, which takes advantage of the large reserves of groundwater within the underlying sediments and the surrounding bedrock.
Once the glaciers melt and retreat, springs appear where this network of groundwater cuts through the surface. Specialists found that methane emissions across Svalbard could exceed 2,000 tonnes over the course of a year, which is equivalent to approximately 10% of the methane emissions resulting from Norway’s annual oil and gas energy industry.
This source of methane is likely to become more significant as more springs are exposed, Kleber warned, “if global warming continues unchecked, then methane release will likely become more extensive.” These sources were not always easy to recognize, so Kleber trained his eye to select them from satellite images.
Zooming in on areas of land exposed by the retreat of 78 glaciers across Svalbard, he looked for telltale blue drips of ice where groundwater had seeped to the surface and frozen. He then traveled to each of these sites by snowmobile to sample groundwater in places where ice was He had blistered due to the accumulation of pressurized water and gas.
When Kleber and the team profiled the chemistry of the water They found that all of the sites studied were highly concentrated with dissolved methane, meaning that, when spring water reaches the surface, there is excess methane that can escape into the atmosphere.
Researchers They also identified localized hotspots of methane emissions., which were closely related to the type of rock from which groundwater emerges. Certain rocks such as shale and coal contain natural gases, including methane, produced by the decomposition of organic matter when the rocks formed.
This methane can move upward through fractures at the surface and in groundwater. “In Svalbard, we are beginning to understand the complexity of melting glaciers. It seems likely that there are more consequences like this that we haven’t discovered yet,” Kleber said.
“The amount of methane escaping from the springs we measured will likely be dwarfed by the total volume of trapped gas lying beneath these glaciers, waiting to leave. That means we urgently need to establish the risk of a sudden increase in methane leakage because glaciers will only continue to retreat,” Hodson concluded.