Parts of Antarctica are turning green faster than expected, with researchers warning that climate change could lead to a devastating influx of invasive species.
鈥淭he scale of the greening trend we found shocked us,鈥� says at the University of Exeter, UK. 鈥淭he rate of change we鈥檙e seeing in terms of increasing vegetation cover is astounding and, worryingly, accelerating.鈥�
Antarctica is warming twice as fast as the global average, . The past few years have seen record high temperatures and record low levels of sea ice around the continent.
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Roland and his colleagues used 35 years of satellite photography taken over the 522,000-square-kilometre Antarctic Peninsula and nearby islands and then calculated the ratio of visible red light to near-infrared light, to provide a measurement of green biomass.
The method has been tested in other harsh environments and has been proven to work, even for vegetation close to the ground such as mosses.
In 1986, less than 1 km虏 of the Antarctic Peninsula was covered in vegetation, but by 2021 this had increased to nearly 12 km虏.
Between 2016 and 2021, the rate at which this vegetation was expanding increased by more than 30 per cent.
In some areas, the amount of vegetation that was turning brown due to stress had also increased, mostly likely due to changes in rainfall or the retreat of ice meaning less summer meltwater was available in specific areas.
鈥淚f I were to make a prediction, I would envisage a growing fraction of the peninsula鈥檚 landscape becoming dominated by a mosaic ecosystem of mosses, lichens, liverworts and fungi,鈥� says Roland.
This increase in such species will lead to greater soil formation, which will raise the risk of colonisation by non-native ones, he says.
鈥淔or us, our findings confirm that the influence of anthropogenic climate change has no limit in its reach. Even on the Antarctic Peninsula, this most extreme, remote and isolated wilderness region, the landscape is changing and these effects are visible from space,鈥� says Roland.
Team member at the University of Hertfordshire, UK, says it was a challenge to get clear images of the Antarctic Peninsula. 鈥淚t is, essentially, the cloudiest place on the planet.鈥�
From a cloud cover perspective, March turned out to be the best month for observing the peninsula from space. 鈥淟uckily, this also coincides with the end of the growing season in the region, and these images subsequently give us the best chance of accurately measuring vegetation extent,鈥� says Bartlett.
at the University of Wollongong, Australia, says the findings mirror vegetation changes seen in the Arctic, but until now no one has been able to show the greening in the Antarctic Peninsula on this scale.
The browning events seen in the study also match what her research has found in moss beds in the East Antarctic, due to changes in water availability and the increase in drying winds.
鈥淭he fact is that when glaciers retreat, it means that there are areas for plants to grow, but only if there鈥檚 enough water,鈥� says Robinson. 鈥淎nd most of the Antarctic is literally a desert in terms of precipitation.鈥�
鈥淚t鈥檚 still a very, very small area of Antarctica that is generally ice-free and we want to keep as much of that ice as possible,鈥� she says.
Nature Geoscience
