Climate

As Warming Takes Root, Antarctica Is Becoming Greener

Average annual temperatures over the Antarctic Peninsula have increased 3 degrees Celsius since the 1950s, encouraging plant growth on the continent.

The Antarctic Peninsula is undergoing a widespread transformation after a half-century of warming, fueling a “greening” at the edges of the inhospitable continent at the bottom of the world, new research concludes.

Average annual temperatures on the peninsula — the panhandle that points toward South America — have gone up nearly 3 degrees Celsius (5.4 degrees Fahrenheit) since the 1950s, when researchers started keeping detailed weather records. And the banks of moss that cover portions of the peninsula point to “a very widespread biological response” to climate change, said Matt Amesbury, a paleoclimatologist at Britain’s University of Exeter.

“Under future warming scenarios, there is likely to be a greening of the Antarctic Peninsula, both in terms of further increases in growth rates and also a likely expansion of the extent of these moss growths,” Amesbury said. As glaciers in the region continue to retreat, “It’s very likely in the future that we will see increased growth rates of the mosses, but also those mosses covering a wider area,” he said.

Amesbury is the lead author of the new study, published today in the scientific journal Current Biology.  The peninsula’s moss banks grow in the summer and freeze in the winter — and core samples from those banks give scientists a window into how the plants behaved as temperatures rose.

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The 150-year record the study collected from those cores reveals how much they grew in a particular year and how well the microbes living among them thrived.

“What we see is for about the first hundred years or so, all of these different proxies kind of tick along nicely at a very low level,” Amesbury said. “And then when we get to around the 1950s or 1980s … we see a dramatic increase in these different parameters across all of our sites and all of our methods.”

The findings are a follow-up to a 2013 study that examined core samples taken from a single point on the peninsula. This study included a total of five core samples taken from the previous location and three new sites on islands offshore; all cores showed signs of increased biological activity.

 “The precise timing of these shifts varied, but the prevalent pattern of change indicates a widespread biological response to increasing temperature,” the study states. 

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Most of Antarctica is covered by ice sheets that average more than 2 kilometers (1.3 miles) thick. Since those ice sheets contain enough water to raise global sea levels by about 60 meters (200 feet), the continent is under intense scrutiny from scientists as temperatures rise. They’re watching a massive crack grow in one of the ice shelves on its fringe, and warn that the western ice sheet has begun a long-term decline.

But the Antarctic Peninsula is warm enough that a handful of plant species can survive. Amesbury said the only two flowering plants in the region are expected to have a similar response to warming — and as more tourists visit the peninsula, there’s an increasing risk that they could bring invasive species with them.

“As the climate warms, the chances that those sorts of plants might take a foothold increases,” he said. “There might be a kind of joker in the pack in that respect.”

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