The Arctic island of Svalbard is so reliably frigid that humanity bet its future on the place. Since 2008, the Svalbard Global Seed Vault — set deep in frozen soil known as permafrost — has accepted nearly 1.4 million samples of more than 6,000 species of critical crops. But, the island is warming six to seven times faster than the rest of the planet, making even winters freakishly hot, at least by Arctic standards. Indeed, in 2017, an access tunnel to the vault flooded as permafrost melted, though the seeds weren’t impacted.
This February, a team of scientists was working on Svalbard when irony took hold. Drilling into the soil, they gathered samples of bacteria that proliferate when the ground thaws. These microbes munch on organic matter and burp methane, an extremely potent greenhouse gas and significant driver of global warming. Those emissions are potentially fueling a feedback loop in the Arctic: As more soil thaws, more methane is released, leading to more thawing and more methane, and on and on.
In some parts of Svalbard, though, the scientists didn’t need to drill. Air temperatures climbed above freezing for 14 of the 28 days of February, reaching 40 degrees Fahrenheit, when the average temperature at this time of year is 5 degrees. Snow vanished in places, leaving huge pools of water. “I brought my equipment to drill into frozen soil and then ended up sampling a lot of soil just with a spoon, like it was soft ice cream,” said Donato Giovannelli, a geomicrobiologist at the University of Naples Federico II and co-lead author of a paper describing the experience, published last week in the journal Nature Communications. “That was really pretty shocking.”
Scientists can now dig with silverware in the Svalbard winter because the Arctic has descended into a crisis of reflectivity. Until recently, the far north had a healthy amount of sea ice, which bounced much of the sun’s energy back into space, keeping the region cool. But as the planet has warmed, that ice has been disappearing, exposing darker water, which absorbs sunlight and raises temperatures. This is yet another Arctic feedback loop, in which more warming melts more sea ice, leading to more local warming, and on and on.
Making matters worse, as temperatures rise in the far north, more moisture enters the atmosphere. For one, warmer seawater evaporates more readily, adding water vapor to the air. And two, a warmer atmosphere can hold more moisture. This leads to the formation of more low-level clouds, which trap heat like blankets — especially in the dark Arctic winter — amplifying the warming. That, combined with the loss of sea ice, is why the Arctic is warming up to four times as fast as the rest of the planet, with Svalbard warming even faster than that.
Researchers on Svalbard say rising Arctic temperatures have led to reduced sea ice cover and rapidly thawing permafrost. These conditions are part of a feedback loop that makes the region especially vulnerable to climate change. Courtesy of James Bradley
During the winter, Svalbard’s soils have historically frozen solid, and scientists assumed this made microbial activity grind to a halt. Reindeer could push through the snow to graze on vegetation. But February’s heat and rain melted the snow, forming vast pools of water that froze once temperatures dropped again. That created a layer of ice that reindeer couldn’t break through. “What we encountered was just so powerful, to be in the middle of this event,” said James Bradley, a geomicrobiologist at the Mediterranean Institute of Oceanography and Queen Mary University of London, co-lead author of the paper. “It really almost all melted over large, large, large areas of the ground. That ground remained frozen, so the water didn’t have too many places to drain away to, so what we also saw was huge pooling of liquid water over the tundra.”
This new climate regime could be profoundly altering the soil microbiome. Scientists assumed that methane-producing bacteria, known as methanogens, stopped proliferating when Svalbard’s soils froze in the winter, just like food in your freezer keeps for months because it’s in a hostile environment for microbes. But with warm spells like this, thawing could awaken methanogens, which could still produce that greenhouse gas even if it then rains and a layer of ice forms at the surface. In addition, that solid cap on the soil will stop the exchange of atmospheric gases into the ground, creating anaerobic, or oxygen-poor, conditions that methanogens love. “In some areas, deeper layers might never freeze completely, which means the methanogens and microbes at depth remain active,” Giovannelli said. “There’s no real winter period.”
Vegetation, too, is changing up there, a phenomenon known as Arctic greening. As temperatures rise, trees and shrubs are creeping north to conquer new territory. The good news is that those plants capture carbon as they grow, mitigating global warming to a certain extent. But the bad news is that dark-colored vegetation absorbs more of the sun’s energy and raises temperatures, just like the exposed ocean does. And shrubs trap a layer of snow against the landscape, preventing the chill of winter from penetrating the soil and keeping it frozen.
The speed of transformation in the Arctic is shocking, even for stoic scientists. And as nations keep spewing greenhouse gases, the feedback loops of the far north are threatening to load the atmosphere with still more methane. “We call this the new Arctic — this is not something that is a one-off,” Giovannelli said. “And on the other side, we’ve probably been a bit too cautious with our warnings regarding the climate. It’s not something for the next generation. It’s something for our generation.”
