The consequences of climate change can be weird and apocalyptic.
By Brian Resnick@B_resnickbrian@vox.com Updated Feb 6, 2018, 11:13am EST
You can find evidence of a changing climate everywhere on Earth. But nowhere are the changes more dramatic than in the Arctic.
Our world’s northern polar region is warming twice as fast as the global average. And the consequences are easy to spot. On average, Arctic sea ice extent is shrinking every summer. The Greenland ice sheet is becoming unstable.
But perhaps most disturbing are the changes occurring underground in the permafrost. Permafrost is a layer of frozen soil that covers 25 percent of the Northern Hemisphere. It acts like a giant freezer, keeping microbes, carbon, poisonous mercury, and soil locked in place.
Now it’s melting. And things are getting weird and creepy: The ground warps, folds, and caves. Roadways built on top of permafrost have becoming wavy roller coasters through the tundra. Long-dormant microbes — some trapped in the ice for tens of thousands of years — are beginning to wake up, releasing equally ancient C02, and could potentially come to infect humans with deadly diseases. And the retreating ice is exposing frozen plants that haven’t seen the sun in 45,000 years, as new radiocarbon dating research suggests.
A recent Arctic Council report says that 20 percent of the permafrost near the surface may melt by 2040. Already scientists have noticed permafrost temperatures slowly climbing. “In the 1980s, the temperature of permafrost in Alaska, Russia and other Arctic regions averaged to be almost 18°F,” the U.S. Geological Survey explained in 2015. “Now the average is just over 28°F.”
A 2010 study in Russia found 0.5°C to 2°C of permafrost warming in the past three decades, bringing some locations dangerously close to thawing and pushing the boundary of permafrost regions ever northward. And the depth of the “active layer” — the top layer of permafrost that thaws in the summertime — is growing deeper in the Arctic regions north of Europe, a sign of instability.
When it thaws, a Pandora’s box is unleashed. To better understand the strange changes in the permafrost, I spoke with Robert Max Holmes, an earth systems scientist with the Woods Hole Research Center. When I reached him by phone, he was in Bethel, Alaska, a small outpost town 400 miles west of Anchorage, and had just come back from an eight-day research and teaching expedition in the wilderness.
A week earlier, Holmes and his students had set up temperature sensors in the soil near their encampment. Their first reading was 0.3°C. “It's barely frozen. And we just sort of sat there stunned. You don't know whether to cry or what. Because you're just like: My God, this whole thing is just going to change in a big way.”
Here’s how.
1) Permafrost has been frozen for millennia. Thawing it is a huge disruption.
The icy mountains near Svalbard, Norway, an arctic archipelago that’s rapidly changing due to climate change. Johnny Harris / Vox
The simplest definition of permafrost is ground that has been frozen for at least two years.
But it’s so much more than that. In much of the Arctic, that ground has been frozen for tens of thousands of years. And a huge amount of it is frozen — permafrost rests in 25 percent of all the land area in the Northern Hemisphere.
National Snow and Ice Data Center
The top few inches (up to a few feet) of the permafrost is what’s known as the “active layer.” This topsoil does thaw with yearly seasonal changes, and is home to a thriving ecosystem. So how do scientists know there’s permafrost underneath it?
“We have these things called thaw depth probes, which is basically just a T-bar, a steel rod that's a centimeter in diameter and 1.5 meters or so long,” Holmes says. They poke the ground with it. “It's like pushing a knife through warm butter or something, and then you hit the bottom of the tray, and boom” — there’s your permafrost.
Eventually, if you dig deep enough, the permafrost again thaws due to heat from the Earth’s core.
Permafrost is like the bedrock of the Arctic (you literally need jackhammers to break it apart). But rising air temperatures in the region are chipping away at this bedrock.
“Half the volume of permafrost may be frozen water,” Holmes says. “When that thaws, the water just runs off. The water may head downhill or the water has a lower volume than is ice, so the ground just slumps and kind of falls apart.”
(The New York Times has a great new interactive showing how much permafrost in the Alaska may inevitably melt.)
2) The biggest threat is carbon
Longyearbyen, a settlement in Svalbard, Norway, is home to a seed vault intended to protect plant genetic diversity amid a changing climate. Its Arctic location may not be as secure as once thought due to rising temperatures and melting permafrost. Johnny Harris / Vox
You can think of the Arctic permafrost as a giant kitchen freezer.
If you put organic (carbon-based) matter in your freezer, the food will stay intact. But if the freezer compressor breaks, it will slowly heat up. As it heats up, bacteria begin to eat your food. The bacteria make the food go rotten. And as the bacteria consume the food, they produce carbon dioxide, methane, and other gases and chemicals that smell terrible.
For tens of thousands of years, permafrost has acted like a freezer, keeping 1,400 gigatons (billion tons) of plant matter carbon trapped in the soil. (That’s more than double the amount of carbon currently in the atmosphere.) Some of the plant matter is more recent, and some is from glacial ice ages that radically transformed a lush landscape into a tundra.
Read more
https://www.vox.com/2017/9/6/16062174/permafrost-melting
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