Plant cover across the Antarctic peninsula has soared more than tenfold over the last few decades, as the climate crisis heats up the icy continent.
Analysis of satellite data found there was less than one sq kilometre of vegetation in 1986 but there was almost 12km2 of green cover by 2021. The spread of the plants, mostly mosses, has accelerated since 2016, the researchers found.
The growth of vegetation on a continent dominated by ice and bare rock is a sign of the reach of global heating into the Antarctic, which is warming faster than the global average. The scientists warned that this spread could provide a foothold for alien invasive species into the pristine Antarctic ecosystem.
Greening has also been reported in the Arctic, and in 2021 rain, not snow, fell on the summit of Greenland’s huge ice cap for the first time on record.
“The Antarctic landscape is still almost entirely dominated by snow, ice and rock, with only a tiny fraction colonised by plant life,” said Dr Thomas Roland, at the University of Exeter, UK, and who co-led the study. “But that tiny fraction has grown dramatically – showing that even this vast and isolated wilderness is being affected by human-caused climate change.” The peninsula is about 500,000km2 in total.
Roland warned that future heating, which will continue until carbon emissions are halted, could bring “fundamental changes to the biology and landscape of this iconic and vulnerable region”. The study is published in the journal Nature Geoscience and based on analysis of Landsat images.
Prof Andrew Shepherd, at Northumbria University, UK, and not part of the study team, said: “This is a very interesting study and tallies with what I found when I visited Larsen Inlet [on the peninsula] a couple of years ago. We landed on a beach that was buried beneath the Larsen Ice Shelf until the shelf collapsed in 1986-88. We found it to now have a river with green algae growing in it!”
“This place had been hidden from the atmosphere for thousands of years and was colonised by plants within a couple of decades of it becoming ice free – it’s astonishing really,” he said. “It’s a barometer of climate change but also a tipping point for the region as life now has a foothold there.”
The acceleration in the spread of the mosses from 2016 coincides with the start of a marked decrease in sea ice extent around Antarctica. Warmer open seas may be leading to wetter conditions that favour plant growth, the researchers said. Mosses can colonise bare rock and create the foundation of soils that, along with the milder conditions, could allow other plants to grow.
Dr Olly Bartlett, at the University of Hertfordshire and also co-leader of the new study, said: “Soil in Antarctica is mostly poor or nonexistent, but this increase in plant life will add organic matter, and facilitate soil formation. This raises the risk of non-native and invasive species arriving, possibly carried by eco-tourists, scientists or other visitors to the continent.”
A study in 2017 showed the rate of moss growth was increasing but it did not assess the area covered. Another study, in 2022, showed that Antarctica’s two native flowering plants were spreading on Signy Island, to the north of the Antarctic peninsula.
Green algae is also blooming across the surface of the melting snow on the peninsula. Trees were growing at the south pole a few million years ago, when the planet last had as much CO2 in the atmosphere as it does today.
