The Earth’s ozone layer, which protects the surface from the sun’s harmful ultraviolet radiation, is set to be back to its full level of effectiveness covering most of the planet by 2040 according to researchers.
The shield, discovered in 1913, was once regarded as humanity’s most serious environmental challenge as it was suffering depletion due to chlorofluorocarbons (CFC) emissions.
First used for fridges in 1928, it was not until 1976 that scientists realised CFCs react with atmospheric ozone (O3), producing oxygen (O2) and depleting the protective layer.
A global move to combat the use of CFCs in household applications such as refrigeration units, air conditioning, and aerosol cans was then introduced.
The Vienna Convention for the Protection of the Ozone Layer, first formed in 1985, and its Montreal Protocol on Substances that Deplete the Ozone Layer, adopted in 1987, represented the first worldwide effort to combat human-driven climatological effects.
The hole in the ozone shield kept growing until the year 2000, but now it is on track to completely recover within two decades across the world, the UN-backed scientific assessment has found.
It will take slightly longer in polar regions, with the hole over the Arctic expected to be fully healed by 2045 and that over the Antarctic by 2066.
The UN report comes out every four years to assess progress on the Montreal Protocol.
Ozone Layer Protection, A Global Success Story
‘Gases like chlorofluorocarbons, or CFCs, destroy stratospheric ozone’ said Scot Miller, assistant professor in the USA’s Johns Hopkins University Department of Environmental Health and Engineering.
‘The report found that emissions of ozone-depleting substances.. like CFCs have dramatically declined over the past 30 years, which spells good news for the recovery of stratospheric ozone.
‘The ozone layer blocks harmful ultraviolet rays from reaching Earth’s surface. This harmful radiation can damage skin and lead to skin cancer and cataracts. It can also harm marine life and some crops.’
Miller praised the international action to protect the stratosphere shield – and compared it with humanity’s approach to tackling wider climate change issues.
He said: ‘I think that the ozone layer is a remarkable story of global cooperation to successfully tackle an environmental problem. The Antarctic ozone hole appeared in satellite ozone measurements as far back as the late 1970s, but scientists initially thought the measurements were an error because they were so low.
‘The first paper to report on the ozone hole was published in 1985, and by 1987 countries around the world had agreed on the Montreal Protocol. Emissions of ODS have plummeted since that time.
‘By contrast, global action on climate change has been more complicated and fraught. Most countries signed on to the 1997 Kyoto Protocol and subsequently to the 2015 Paris Agreement—treaties that target global reductions of greenhouse gas emissions. However, those emissions continue to climb year after year, except for a short-lived reduction during the early months of the COVID-19 pandemic.
‘Arguably, the ozone layer was an easier cause to rally around; ozone destruction was an immediate threat to global health, ODS were only being emitted by a limited number of industries, and there were chemical alternatives to many ODS.
‘By contrast, climate change is arguably a more long-term, existential threat, and greenhouse gases are emitted by countless human activities.’