TODAY, we know Antarctica as a snow-dominated landscape, a continent covered with a permanent glacial ice-sheet. However, 41 million years ago, Antarctica looked very different: it was carpeted with lush forests that rang with birdsong with distant snow-capped mountains. That began to change 31 million years ago, as global temperatures dropped. 

The transition is described by the palaeobiologist Thomas Halliday in his book Otherlands (2022). Soon (in geological terms, that is) the ice descended from Antarctica’s mountaintops, “spreading across the entire continent and forcing out almost all plants and animals.” Of Antarctica’s range of animals, only the emperor penguins were able to adapt at the right pace and retain their habitat on what became Earth’s most forbidding continent. 

Antarctica’s northernmost point is the Antarctic Peninsula. Unlike the rest of Antarctica it is not completely icebound: only 80 per cent is currently covered by ice. But the remaining 20 per cent is usually rocky. Now, new research published this week in Nature Geoscience confirms that climate change is affecting Antarctica’s plant life. 

Between 1986 and 2021, the area of the peninsula covered by moss has grown tenfold. In the last five years of that period, the mossy areas grew at an increased rate than ever before, equivalent to about 60 new football fields each year. The total area of vegetation on the peninsula is now larger than Richmond Park. 

Mapping vegetation cover on a large and remote continent is not straightforward. Satellites orbiting the Earth take images in visible red and near-infrared light. Because plants absorb red light and reflect near-infrared, the ratio of the two can be used to infer whether the image contains plants. 

However, much of the peninsula is shrouded in persistent cloud cover: regularly more than 80 per cent of satellite images are regularly covered in cloud. Since that cloud cover is also potentially changing with climate change, this could influence the results: maybe the increase in vegetation is just because more of it is visible from space? But the researchers in the Nature Geoscience study showed that though the amount of observable land does affect their results, the correlation is not perfect. That suggests that the increase is a genuine signal of more plants on Antarctica.

Antarctica’s flora is rather limited but unique: lichens, mosses and liverworts that are all adapted to cold temperatures and bare rock. The increasing growth of moss could increase not only the area of land that is covered but also the depth of the vegetation layer, creating the conditions needed for the development of soil. Once that is in place, plant species from beyond Antarctica might be able to gain a foothold here; for example, from seeds brought to the continent on the shoes of unwitting visitors.

This example shows us that the world we think we know isn’t really as stable as it seems. There is nothing preordained that means Antarctica is “meant” to be covered in ice. Earth’s climate is always changing. Although ice spread over Antarctica 33 million years ago, trees have made another brief return in the interim. A tundra-like ecosystem grew as temperatures warmed slightly, with southern beech trees growing at the South Pole. They only died out again around 2.5 million years ago. 

Aside from the potential introduction of new competitors or predators onto the continent, Antarctic species face direct threats from the ongoing human-caused climate crisis. However, these past changes shouldn’t alleviate concerns about the ongoing climate change that is being caused by humans. The alarming rate of change is producing not only extreme weather and disasters for people around the world, but is also placing huge stress on ecosystems and eliminating Earth’s biodiversity. The delicate balance of the Antarctic ecosystem is already seeing these effects.  

At one level, it is fascinating to see ecosystems adapting. It is a reminder that as well as the destruction of some habitats, climate change also means the opening up — or perhaps the rediscovery — of other ones. Life is resilient. But within that resilience, species go extinct. Where change is too extreme or too fast, almost everything can go extinct. It seems probable that the increase in vegetation on Antarctica would spell disaster for existing Antarctic species that are exquisitely adapted to the conditions, and so would be vulnerable to new competitors from elsewhere. Like other island species such as the dodo and the greak auk, they face the possibility of extinction. 

In the BBC series Frozen Planet II, Adelie penguins were shown shivering on the Antarctica peninsula. Not because of the cold temperatures, but because of increased rainfall: the penguins, evolved for a dry and cold climate, simply cannot tolerate being continuously wet. The ground becomes muddy, and many young chicks are unlikely to survive. When the film crew visited what was once a large penguin colony on the west of the peninsula, they found penguins sheltering between patches of green. That increase in plant life is a sign of the dramatic change the peninsula is undergoing.

Though most of Antarctica remains free of plants, the rapid spread of vegetation documented by this latest research is symbolic. It is an urgent reminder of the need for governments around the world to agree on a rapid plan for transition away from fossil fuels.