Warming Temperatures Are Turning Antarctica Green

Rising temperatures over Antarctica's harsh landscape are causing two native plant species to flourish and spread across the continent. Between 2009 and 2019, plant cover has increased more than in the last 50 years combined and corresponds with rising air temperatures and declining fur seal populations, reports Phoebe Weston for the Guardian. The study published this week in Current Biology is the first to show the accelerated impacts of climate warming in polar ecosystems.

"Antarctica is acting as a canary in a coal mine," Nicoletta Cannone, an ecologist at the University of Insubria and the study's lead author, told Gizmodo's Molly Taft.

Antarctic hair grass, Deschampsia Antarctica, and Antarctic pearlwort, Colobanthus quitensis, are the only two native flowering plant species on the southernmost continent. They can withstand the continent's frigid temperature and photosynthesize at temperatures below zero while covered in snow, Cannone explained to Gizmodo.  

Researchers focused their observations on these plants on Signy Island and compared them to extensive records detailing plant growth recorded since the 1960s, Gizmodo reports. The team found that the plants are flourishing in a warmer climate. Antarctic pearlwort, a small plant with yellow blossoms, grew five times faster between 2009 and 2018 than growth rates observed between 1960 and 2009, per the Guardian. Hair grass, on the other hand, grew ten times more in the past decade than in other years.

Scientists previously thought that Antarctica was immune to global warming. However, studies have shown that the continent has warmed up three times faster than the rest of the world within the last three decades. The continent has also seen a record amount of ice loss. Between 2008 and 2015, ice loss increased by 36 billion gallons per year, according to Gizmodo.  

The team suspects the primary cause of the plants' increasing growth is warming summer air. In the past decade, summer temperatures on Signy Island have increased between .36 Fahrenheit to .49 Fahrenheit each year with the exception of one cold spell recorded in 2012, the Guardian reports. In general, Signy Island's mean annual average air temperature has increased by 1.8 degrees Fahrenheit between 1960 and 2018.

Other factors that may have contributed to the plant growth in Antarctica are dwindling fur seal populations, reports New Scientist's Alex Wilkins. Fewer fur seals on the island mean fewer plants are trampled over, per the Guardian. But warmer temperatures seem to be the most evident link and could spell trouble for the fragile ecosystem.

An increase of native plant species can change the chemical makeup of the continent's soils. This can change how organic matter decomposes and degrade the permafrost, per the Guardian. Higher temperatures may also pave the way for invasive species to outcompete native plants. 

"The study shows that further increases in populations of these plant species can be expected as Antarctica warms in future decades, leading to a greening of the region, but that there may also be increased risks to ecosystems associated with the establishment of alien plant species," Kevin Newsham, a terrestrial ecologist not involved with the study tells the Guardian.

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a daily correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.