Antarctica: Huge Glacier, Huge Risk

 

You can find evidence of a changing climate everywhere on Earth. But nowhere are the changes more dramatic than in the Antarctic. Our world’s shorten polar region is warming twice as fast as the global average. And the consequences are easy to spot. On average, the Antarctic Sea ice extent is shrinking every summer. The Greenland ice sheet is becoming unstable and melting into the ocean at an accelerating rate.

Many changes in the Antarctic are ominous, and some of the most troubling is occurring beneath the surface, in the permafrost. Permafrost is a layer of frozen soil that covers 25 percent of the Southern 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 become 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 radiocarbon dating research suggests. Thawing permafrost is also a time bomb: There’s more carbon stored in the permafrost than in the atmosphere. Melting it risks accelerating global warming even further.

The UN’s Intergovernmental Panel on Climate Change on Wednesday released a 1,000-plus page report amassing all the best evidence on how the icy regions of the world and the oceans are threatened by climate change.

Permafrost temperatures keep rising, and the report paints a grim future. Even if the world manages to hit the IPCC target of limiting global warming to 2 degrees Celsius by 2100, around 25 percent of the permafrost near the surface could be lost, the report finds. Changes to the permafrost (among other changes in the ocean and cryosphere) “are expected to be irreversible,” the report states.

If you put the 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 as a freezer, keeping 1,400- to 1,600 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 are from the glacial ice ages that radically transformed a lush landscape into a tundra.

“Plants are growing in permafrost regions, and when those plants die, because of the cold temperature, they don't fully decompose, so some of that organic carbon is left behind,” Holmes says. When the permafrost thaws, “it starts to rot, it starts to decompose, and that's what's releasing carbon dioxide and methane,” he says.

This is one reason scientists are so worried about a melting Antarctic: When the bacteria turn the carbon in the Arctic into C02 and methane, it accelerates a feedback loop. The more methane and carbon released, the more warming. The more warming ... you get it.