Melting glaciers and methane emissions

The Svalbard archipelago is one of the fastest-warming places on the planet. As GABRIELLE KLEBER explains, its glaciers are melting at an alarming pace, leaving bubbling seeps of methane gas behind. Methane is a potent greenhouse gas that contributes substantially to global temperature rise, compounding the problem.

More than half of Svalbard is covered by the ice of 1,600 glaciers. The remaining land is exposed to the Arctic elements—so deeply frozen that it stays that way year-round. Together, the glaciers and permafrost create a solid, impermeable layer that caps the rocks beneath.

In Svalbard and other parts of the Arctic, many of these deeper rocks are rich in organic carbon, including methane. As long as the cap of glaciers and permafrost remains frozen, the methane can stay sealed. But as glaciers melt away and permafrost thaws, the methane can find its way to the surface, where it is released into the atmosphere.

As Svalbard’s massive glaciers melt, they are exposing land that has been covered by ice for a long time. In these recently exposed “forefields,” we find that many groundwater springs are starting to emerge. These waters have been stored within the rocks beneath glaciers and permafrost, but with the removal of their frozen cap, they can reach the surface. The problem is that they contain methane gas, which is dissolved into the groundwater as the water flows through rocks. Like a cap being removed from a bottle of soda, the gas is released into the atmosphere quickly when the groundwater reaches the surface.

Measuring the methane in groundwater springs

I was part of a research team from Norway and the UK that wanted to understand how much methane gas is being released by these groundwater springs. Travelling by snowmobile or on skis, we set off on a mission to visit as many springs as we could. We reached 78 different glaciers on Svalbard and took samples at more than 120 groundwater springs so we could measure the levels of methane in the water. In all but one spring, we found that the water contained very high concentrations of methane—in some cases, up to 600,000 times higher than a normal body of water. By the time this water reaches the surface, it is carrying a lot of excess methane.

In total, we believe that the groundwaters gurgling up in front of glaciers on Svalbard are emitting up to 2,310 tons of methane per year. That’s like 229 million party balloons’ worth of methane being released into the atmosphere every year. To put that in context, it’s also roughly equivalent to the annual methane emissions from 30,000 cows. Considering that there are more than 900 million cattle worldwide, the methane emissions from glacial groundwaters on Svalbard are dwarfed by emissions from industries like agriculture and waste management. But what’s troubling is that Svalbard is certainly not the only place where groundwater emissions of methane are happening, and it is unclear how many more may turn up as the Arctic continues to warm.

The impact of geology

The levels of methane in the groundwater springs we measured appeared to be connected to the type of geology that the water emerges from. We found that the waters with the highest concentrations had flowed through underground layers of shale rock. The shale on Svalbard was formed up to 160 million years ago from mud at the bottom of a shallow sea that was compressed into rocks. Lots of organic material, such as plant life and small marine organisms, was compacted into these layers of rocks as they formed. Over time, under high pressure and temperatures, this material turns into fossil fuels, like methane.

This means the methane that’s being flushed out of the rocks and brought to the surface by the groundwater now may be ancient gas that’s been sequestered for millions of years.

This is concerning because we know there are large reservoirs of fossil fuels, including methane, stored deep within the rocks in many regions of the Arctic. Therefore, we should expect that this phenomenon is widespread, and that methane is seeping out in front of retreating glaciers across the Arctic. Moreover, as glaciers continue to melt at an accelerating pace, we believe methane emissions from shale rock will amplify.

Melting glaciers and thawing permafrost are uncovering pathways for ancient methane gas to be unearthed—a feedback loop caused by climate change. These methane emissions are out of our direct control: once this release mechanism has been triggered, we can neither stop it nor reverse it.

What we can do is focus on drastically reducing the emissions that are within our control. Doing so could help to curtail more methane from being uncovered by melting glaciers.