Climate Change is Turning Antarctica's Snow Green

As the planet warms, parts of the planet are going green—and not in the environmentally friendly way. Snow in coastal Antarctica is literally turning the color green.

In a study published in Nature Communications on Tuesday, a team of scientists mapped out green snow on the Antarctic Peninsula for the first time. The researchers used satellite images from the European Space Agency taken between 2017 and 2019, and combined those with observations they made themselves in a trip to Antarctica’s Ryder Bay, Adelaide Island, the Fildes Peninsula, and King George Island.

“We identified 1,679 separate blooms of green algae on the snow surface,” Matt Davey, a professor in the University of Cambridge’s Department of Plant Sciences who led the study, told Earther in an email.“We focused on the green blooms as these were the most visible from space.”

As it gets warmer, algae spores are germinating on the surface of Antarctica’s snow. While the green was the easiest to spot from space, algae is also turning snow wild colors like red and orange. The team found that the green blooms are mostly occurring on snow around the Antarctic coastline, particularly on islands along the west coast of the Antarctic Peninsula. The peninsula is the fastest warming part of the continent due to the climate crisis, and the western areas are among its fastest warming areas. The algae thrives there on the runoff from melting snow.

The research also shows that green snow occurs in areas where wildlife live because animal poop fertilizes algae. Over 60 percent of the blooms they mapped were found within three miles of penguin colonies, and blooms were also often observed near where birds nest and seals hang out on the shore.

As the climate crisis progresses, patterns of green snow will change. Almost two thirds of the green snow the scientists found was on smaller, low-lying islands. As the peninsula heats up, some of those islands may lose their summer snow, and with it, their snow algae. Those losses could be more than offset by larger blooms on the north of the peninsula and the South Shetland Islands, likely resulting in more algae overall.

It’s not clear exactly what the effects of all this green snow will be. It can create some benefits by sucking carbon out of the atmosphere. The blooms the researchers mapped can remove as much carbon from the atmosphere as driving a car a million miles would create. But in the scheme of all atmospheric carbon, that impact is tiny.

“I would say that the blooms are certainly not enough to help get rid of the excess carbon dioxide from human-caused emissions,” said Davey.

The researchers are concerned that the green snow could end up creating more problems. Studies on snow algae in Greenland have found it can increase the amount of sunlight and heat that snow absorbs, which can cause ice to melt faster. That’s bad news, because Antarctica has already seen ice loss triple in the past decade. When that ice melts, it raises sea levels and could overwhelm our coasts. So even though green snow looks pretty cool, more of it may not be such a good thing.

Dharna Norr, May 2020
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