- Ozone hole over the Antarctic is lasting for longer – posing danger to wildlife
- READ MORE Ozone Hole has been ‘remarkably massive’ over the past four years
It’s well known that Earth’s ozone layer offers a protective barrier from the sun’s harmful rays.
Unfortunately, a famous hole in the layer exists over the Antarctic for a few months a year, letting in cancer-causing ultraviolet (UV) light.
Now, researchers warn that the hole is lingering continent for several weeks longer, compared with four years ago.
This means Antarctic wildlife such as seals and penguins are at greater risk of getting sunburnt, while other plants and animals are affected too.
Animals can get cancer from UV radiation, just like humans, although fur and feathers offer some protection.
The new study was led by Sharon Robinson, climate change biologist and Antarctic researcher at the University of Wollongong in Australia.
The researchers referred to NASA data from satellite instruments that monitor the ozone layer while compiling evidence on the effect of UV on various species.
‘If ozone holes last longer, summer-breeding animals around Antarctica’s vast coastline will be exposed to high levels of reflected UV radiation,’ Robinson and colleagues say in The Conversation.
‘More UV can get through, and ice and snow is highly reflective, bouncing these rays around.’
The ozone hole doesn’t stay the same size throughout the year – in fact, it opens up and closes annually as the seasons and temperatures change.
Usually, the ozone hole opens up around August and reaches its widest extent around October before closing again in late November.
Fortunately, this is a period when most Antarctic animals and plants are protected by snow and sea ice cover.
But the experts found that the hole is lasting longer – into summer – when this cover has melted, putting them at risk.
What makes this worse is that December peak breeding season for many Antarctic animals.
‘Our new research found that instead of closing up during November it has stayed open well into December,’ Robinson and colleagues say.
‘This is early summer – the crucial period of new plant growth in coastal Antarctica and the peak breeding season for penguins and seals.’
Adult penguins and seals have protective feathers and fur, but their young that are yet to grow this covering may be more vulnerable.
Meanwhile, Antarctic hairgrass, the cushion plant and various mosses emerge from under snow in late spring, meaning they will be particularly exposed to maximum UV levels.
Antarctic mosses actually produce their own sunscreen to protect themselves from UV radiation, but this comes at the cost of reduced growth.
And krill – the small marine crustacean – will dive deeper into the water when UV radiation is too high.
This could make survival more difficult for the penguins, seals, whales and other marine life that feed on them, the researchers point out.
As for what’s been causing the hole to last longer, the team point to series of ‘unusual events’ between 2020 and 2023.
These include the record-breaking 2019-2020 Australian bushfires and the huge underwater volcanic eruption off Tonga.
‘Volcanoes and bushfires can inject ash and smoke into the stratosphere,’ the team explain.
‘Chemical reactions occurring on the surface of these tiny particulates can destroy ozone.’
They also point to three consecutive years of La Niña, the weather phenomenon that causes cooler, wetter conditions.
The academics ‘don’t know for sure’ what type of damage increased UV exposure will be doing to Antarctic species, because most research in this area has been done in zoos.
They also don’t know if the longer-lasting ozone hole will continue.
The new study, published in the journal Global Change Biology, adds to concerns over the ozone hole’s overall size.
Another team of experts recently warned that the ozone hole has been ‘remarkably massive’ over the past four years.
It wasn’t until the 1980s that the ozone hole was first discovered, by British meteorologist Jonathan Shanklin.
The hole – which hit the global headlines – was created by the release of human-made chemicals, particularly CFCs (chlorofluorocarbons), into the atmosphere.
This discovery led to the Montreal Protocol, an international agreement to halt the production of CFCs, signed in December 1987, and mend the hole.
The UN has said that the ozone hole could be mended by 2040 largely due to the ban on CFCs, which are still lingering in Earth’s atmosphere.
However, climate change may be delaying the recovery of our ozone layer by, for example, making bushfires more common and more severe, the authors of this new study warn.
‘Although the ozone layer is expected to recover before the end of the 21st century, a hole over Antarctica continues to appear each year,’ they say.
‘Climate change, including changing wind patterns and strength, and particularly declining sea ice, are likely to compound UV-B exposure of Antarctic organisms, through earlier ice and snowmelt, heatwaves and droughts.’
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.