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Amidst all the chaotic news from around the world (see floods, royal fall, January 6 riots rerun), scientists have finally seen some positive news.
In a new UN report, experts have revealed that the ozone layer is officially on track to regain full strength within decades.
And although that doesn’t mean all of ours climate crisis woes have been resolved (far from it) is a rare nugget of optimism about our future.
Why is the ozone layer so important?
The ozone layer is the thin part of the Earth’s atmosphere that absorbs most of the sun’s ultraviolet radiation.
If the ozone layer is weakened and radiation penetrates through it, it could cause significant damage to all life on Earth and the entire planet.
Ultraviolet rays affect DNA, cause sunburn, and increase long-term problems like skin cancer.
Why is the ozone layer so damaged?
The ozone layer began to thin in the 1970s due to the emission of chemicals from spray cans, refrigerators, foam insulation and air conditioners, called chlorofluorocarbons.
It wasn’t until 1985 that scientists discovered a huge hole in the ozone layer, which continued to grow until 2000.
The largest hole at that time stretched to an astonishing size – 29.9 million square kilometers.
Why do scientists now believe this will be fixed sooner rather than later?
The Montreal Protocol, signed in 1987 and in force since 1989, pledged 46 countries to phase out chemicals believed to have damaged the ozone layer.
It then became the first UN treaty to be universally ratified.
Nearly 99% of these banned substances have already been phased out, with China in particular working to phase out the CFC-11 chemical.
A new report says Chinese emissions threatened to delay the layer’s recovery, but scientists now believe it only delayed it by a year.
Over 100 of these compounds have been banned and phased out over time.
After 2000, the effect of the protocol finally began to be felt as the hole stopped growing – although progress is not fast.
For example, in 2020, the largest hole found in the ozone layer was 24.8 million square kilometers wide. This is only a small but significant change from the largest hole seen in 2000, which was 5 million square kilometers larger.
Although the protocol was announced decades ago, the delay in recovery is partly due to the accumulation of chemicals.
They do not get into the atmosphere immediately, but over time they break down, destroying the ozone layer. So the full effect of the chemicals being released now will not be felt for some time yet.
If current policies are maintained, the ozone layer should return to 1980 levels this century.
As one of the authors of the report, Stephen A. Montzka, said: “Emissions have fallen incredibly sharply.”
In 2066 it should return to 1980 levels in Antarctica – which was the most affected area – and in 2045 it should return to 1980 levels in the Arctic.
In about two decades (2040), the ozone layer between the polar regions should reach pre-1980 levels.
“Ozone recovery is on track,” said David W. Fahey, director of the National Oceanic and Atmospheric Administration’s Chemical Sciences Laboratory and co-chair of the protocol’s scientific review panel.
He said the “peak depletion” of the ozone layer around the world was “beyond” and suggested that this was due to the effective “control measures” of the Montreal Protocol that all nations had adopted.
However, scientists warn that the recovery of the ozone layer is not guaranteed.
Measures that have been proposed to reduce global warming may actually undo this progress, most notably the proposal to send millions of sulfur dioxide into the upper atmosphere, known as stratospheric aerosol injections.
It was intended to cool the atmosphere with these aerosols to reflect the sun’s rays before they reached the surface, but doing so could set back recovery plans – and disrupt the weather.
This combination of images shared by NASA shows areas of low ozone over Antarctica in September 2000, left, and September 2018. Purple and blue are where ozone is least, yellow and red where ozone is least there is more ozone.
What does this mean for the climate crisis?
Damage to the ozone layer does not have a direct impact on the climate crisis, but by reducing the amount of harmful emissions it should – indirectly – contribute to mitigating global warming.
Many ozone-depleting chemicals are greenhouse gases, which means phasing them out will still prevent a warming of around 0.5°C by mid-century.
However, this is by no means a silver bullet to solve the climate crisis, as evidenced by the extreme weather patterns we continue to experience around the world.
But this is one of several steps we have taken recently that show that our approach to climate is changing.
For example, the UK also leads the Global Ocean Alliance, which aims to improve biodiversity around the world. It wants to protect at least 30% of the global ocean by 2030 – known as the 30/30 goal.
Acid rain, a crisis that emerged in the 70s, 80s and 90s, is now largely seen as a thing of the past, now the production of harmful products such as sulfur dioxide emissions has been reduced. Similarly, leaded gasoline is banned in most developed countries.