Colorado Over the past 25 years, the ozone hole that forms over the Antarctic each spring has begun to shrink.
But over the past four years, the hole has shrunk but it has remained unusually long. Our new research found that instead of closing during November, it remained open until December. It is the beginning of summer – a critical period of new plant growth in coastal Antarctica and peak breeding season for penguins and seals.
This is a matter of concern. When the ozone hole forms, more ultraviolet rays enter the atmosphere.And while penguins and seals have protective coverings, their babies may be more vulnerable. Why does ozone matter?
Over the past half century, we damaged Earth's protective ozone layer by using chlorofluorocarbons (CFCs) and related chemicals. Due to coordinated global action these chemicals are now banned.
Because CFCs have a long half-life, it will take decades for them to be completely removed from the atmosphere. As a result, we still see ozone holes forming every year.The majority of ozone loss occurs over Antarctica. When the hole is formed the UV index doubles, reaching peak levels. We can expect to see more than 14 UV days in the summer in Australia or California, but not in the polar regions.
Fortunately, most species on land are dormant and protected beneath the ice when the ozone hole opens in early spring (September to November). Marine life is protected by sea ice cover and Antarctica's moss forests lie beneath the ice.Protective ice caps have so far helped protect most life in Antarctica from ozone depletion.
Unusually long-lived ozone holeThe ozone hole persisted into December in a series of unusual events between 2020 and 2023. The record-breaking 2019-2020 Australian bushfires, underwater volcanic eruptions in Tonga, and three consecutive years of La Nina volcanoes and bushfires could spread ash and smoke into the stratosphere. Chemical reactions occurring on the surface of these small particles can destroy ozone.
These long-lasting ozone holes coincided with significant loss of sea ice, which meant many animals and plants would have less places to hide.What effect does strong UV radiation have on ecosystems? If the ozone hole persists for a long time, summer breeding animals around Antarctica's habitat coastline will be exposed to higher levels of reflected UV radiation. More UV CA penetrates, and snow and ice are highly reflective, bouncing these rays around.
In humans, high UV exposure increases the risk of skin cancer and cataracts. But we don't have fur or feathers. While penguins and seals have skin protection, their eyes are not protected.Is it causing harm? We don't know for sure. Very few studies report on what effects U radiation has on animals in Antarctica. Most is done in zoos, where researchers study what happens when animals are exposed to artificial light. Still, it is a matter of concern. Excess UV radiation in early summer can be especially harmful to young animals, such as penguin chicks and seal pups that hatch or are born in late spring.
As plants such as Antarctic hairgrass, Deschampsia antarctica, cushion plant, Colobanthus queitensis and many mosses emerge from under the snow in spring, they will be exposed to maximum UV levels.Antarctic mosses actually produce their own sunscreen to protect themselves from UV radiation, but it comes at the cost of reduced growth. Trillions of tiny phytoplankton live beneath the sea ice. These microscopic floating algae also produce sunscreen compounds, called microsporin amino acids.
What about sea creatures? If UV radiation is too high, krill will dive deep into the water column, while fish eggs usually contain melanin, a protective compound similar to that in humans, although not all fish life stages are as protected.
Sea ice extent has declined in four of the last five years, a severe consequence of climate change.Less sea ice means more UV light can penetrate the ocean, where it makes it harder for Antarctic phytoplankton and krill to survive. A lot depends on these tiny organisms, which form the basis of the food web. If they find it difficult to survive, hunger will devastate the food chain. Due to climate change, Antarctica's water is also becoming warmer and more acidic.
An uncertain outlook for Antarctica
We should rightly celebrate the success of banning CFCS – a rare example of fixing an environmental problem.But it may be premature. For example, climate change may delay the recovery of our ozone layer, causing bushfires to become more common and more severe. Ozone geoengineering proposals such as adding sulphate to the atmosphere to reflect sunlight May be affected by spraying, as well as more frequent rock launches.
If recent trends continue, and the ozone hole persists into the summer, we can expect to see further damage to plants and animals—which is also linked to other threats. We don't know what long-term Whether the ozone hole will continue or not. But we know that the atmosphere is behaving in unprecedented ways because of climate change.To keep ozone recovery on track, we need to take urgent action to reduce the carbon emitted into the atmosphere. (talk) AMS
But over the past four years, the hole has shrunk but it has remained unusually long. Our new research found that instead of closing during November, it remained open until December. It is the beginning of summer – a critical period of new plant growth in coastal Antarctica and peak breeding season for penguins and seals.
This is a matter of concern. When the ozone hole forms, more ultraviolet rays enter the atmosphere.And while penguins and seals have protective coverings, their babies may be more vulnerable. Why does ozone matter?
Over the past half century, we damaged Earth's protective ozone layer by using chlorofluorocarbons (CFCs) and related chemicals. Due to coordinated global action these chemicals are now banned.
Because CFCs have a long half-life, it will take decades for them to be completely removed from the atmosphere. As a result, we still see ozone holes forming every year.The majority of ozone loss occurs over Antarctica. When the hole is formed the UV index doubles, reaching peak levels. We can expect to see more than 14 UV days in the summer in Australia or California, but not in the polar regions.
Fortunately, most species on land are dormant and protected beneath the ice when the ozone hole opens in early spring (September to November). Marine life is protected by sea ice cover and Antarctica's moss forests lie beneath the ice.Protective ice caps have so far helped protect most life in Antarctica from ozone depletion.
Unusually long-lived ozone holeThe ozone hole persisted into December in a series of unusual events between 2020 and 2023. The record-breaking 2019-2020 Australian bushfires, underwater volcanic eruptions in Tonga, and three consecutive years of La Nina volcanoes and bushfires could spread ash and smoke into the stratosphere. Chemical reactions occurring on the surface of these small particles can destroy ozone.
These long-lasting ozone holes coincided with significant loss of sea ice, which meant many animals and plants would have less places to hide.What effect does strong UV radiation have on ecosystems? If the ozone hole persists for a long time, summer breeding animals around Antarctica's habitat coastline will be exposed to higher levels of reflected UV radiation. More UV CA penetrates, and snow and ice are highly reflective, bouncing these rays around.
In humans, high UV exposure increases the risk of skin cancer and cataracts. But we don't have fur or feathers. While penguins and seals have skin protection, their eyes are not protected.Is it causing harm? We don't know for sure. Very few studies report on what effects U radiation has on animals in Antarctica. Most is done in zoos, where researchers study what happens when animals are exposed to artificial light. Still, it is a matter of concern. Excess UV radiation in early summer can be especially harmful to young animals, such as penguin chicks and seal pups that hatch or are born in late spring.
As plants such as Antarctic hairgrass, Deschampsia antarctica, cushion plant, Colobanthus queitensis and many mosses emerge from under the snow in spring, they will be exposed to maximum UV levels.Antarctic mosses actually produce their own sunscreen to protect themselves from UV radiation, but it comes at the cost of reduced growth. Trillions of tiny phytoplankton live beneath the sea ice. These microscopic floating algae also produce sunscreen compounds, called microsporin amino acids.
What about sea creatures? If UV radiation is too high, krill will dive deep into the water column, while fish eggs usually contain melanin, a protective compound similar to that in humans, although not all fish life stages are as protected.
Sea ice extent has declined in four of the last five years, a severe consequence of climate change.Less sea ice means more UV light can penetrate the ocean, where it makes it harder for Antarctic phytoplankton and krill to survive. A lot depends on these tiny organisms, which form the basis of the food web. If they find it difficult to survive, hunger will devastate the food chain. Due to climate change, Antarctica's water is also becoming warmer and more acidic.
An uncertain outlook for Antarctica
We should rightly celebrate the success of banning CFCS – a rare example of fixing an environmental problem.But it may be premature. For example, climate change may delay the recovery of our ozone layer, causing bushfires to become more common and more severe. Ozone geoengineering proposals such as adding sulphate to the atmosphere to reflect sunlight May be affected by spraying, as well as more frequent rock launches.
If recent trends continue, and the ozone hole persists into the summer, we can expect to see further damage to plants and animals—which is also linked to other threats. We don't know what long-term Whether the ozone hole will continue or not. But we know that the atmosphere is behaving in unprecedented ways because of climate change.To keep ozone recovery on track, we need to take urgent action to reduce the carbon emitted into the atmosphere. (talk) AMS
