Save the ozone layer In 1985, scientists discovered a large gaping hole in the layer. Two years later, 46 countries signed the Montreal Protocol, promising to eliminate harmful chemicals.
Later, the agreement became the first UN treaty to receive universal ratification, and nearly 99 percent of ozone-depleting substances have been eliminated.
The Antarctic ozone hole continued to grow until the year 2000, after which its size and depth began to gradually improve.
Now, according to a report produced jointly by UN, US, and EU agencies, the Montreal Protocol is functioning as expected.
It states that if current policies are maintained, the ozone layer will be restored to 1980 levels – before the appearance of the ozone hole – at various times and locations:
- 2066 over the Antarctic, where ozone depletion was at its worst;
- 2045 over the Arctic; and approximately twenty years from now everywhere else.
- Due to solar radiation, ozone depletion is harmful, but it is not a major cause of climate change.
The report suggests that saving the ozone layer has had a positive effect on global warming because some of the harmful chemicals that were phased out are potent greenhouse gases.
The scientists discovered that this phase-out will have prevented up to 1°C of warming by the middle of the century compared to increasing their use by 3% per year.
While the report has been hailed as good news and proof that swift international action to prevent environmental crises can be effective, it warns that continued progress on the ozone layer is not assured.
For instance, proposals to limit global warming by injecting millions of tonnes of sulphur dioxide into the stratosphere – known as stratospheric aerosol injection – could reverse the recovery of the ozone layer.