Regulations banning ozone-depleting substances are paying off and scientists believe that the ozone layer could fully recover.
The ozone layer absorbs most of the sun’s ultraviolet radiation, acting as a protective shield in the Earth’s stratosphere. Without it, very little life on earth would survive.
In the 1980’s it was found that substances called chlorofluorocarbons (CFCs) were destroying the ozone layer.
These were used in aerosol cans, refrigerants, as blowing agents for foams and packing materials, and as solvents.
CFCs are broken up by ultraviolet radiation after floating into the atmosphere. Chlorine atoms are released which destroy ozone molecules
This discovery led to the 1987 Montreal Protocol, which called for the phasing out of CFSs and other damaging substances. The protocol came into effect in 1989.
Now, more than three decades later, scientific observations are suggesting that efforts to slow down ozone destruction are paying off.
And that the ozone layer actually has the potential to make a full recovery.
Winds of change
A scientific document recently published on Nature website, has underlined how global action can help reverse environmental damage.
Antara Banerjee, of the University of Colorado Boulder and the National Oceanic and Atmospheric Administration, is the lead author of the study.
In an interview with the Independent, she explained how the movements of jet stream winds are able to assist scientists in studying the ozone layer.
A jet stream is a current of fast-moving air which is usually several thousand kilometers long and wide, but relatively thin.
Also to be factored in are carbon dioxide emissions as these can affect the jet streams.
Banerjee pointed out that due to ozone depletion, the southern hemisphere jet stream had slowly been moving closer to the south pole in the last couple of decades of the 20th century.
But since 2000, the situation has changed, an encouraging sign that the Montreal Protocol could be working.
“Our study found that movement has stopped since 2000 and might even be reversing,” Banerjee said.
“The pause in movement began around the same time that the ozone hole started to recover.
“The emissions of ozone-depleting substances that were responsible for the ozone hole – the CFCs from spray cans and refrigerants – started to decline around 2000, thanks to the Montreal Protocol.”
Long-term recovery is possible
It could take some time for the ozone to recover. And sustained efforts to adhere to the Montreal Protocol and to keep carbon emissions down would be crucial.
But Banerjee believes the ozone layer does have the potential to recover in this century.
“If we keep adhering to this protocol then the ozone hole is projected to recover. At different times, in different parts of the atmosphere. In some regions, we think it might happen in the next couple of decades and in others much later in the century.”
The Montreal Protocol has been revised several times, most recently in 2016.
“Perhaps the single most successful international agreement to date has been the Montreal Protocol,” former Secretary-General of the United Nations Kofi Annan once said.
IMAGE FEATURED: eevl