Today marks World Ozone Day, with the theme for this year being ’32 Years and Healing’. This year’s theme celebrates the 32 years of international cooperation to protect the ozone layer, under the Montreal Protocol.
The event was established by the United Nations General Assembly, to mark the day in 1987 that the Montreal Protocol was signed.
The United Nations Environment Programme stated: “On this World Ozone Day, we can celebrate our success. But we must all push to keep hold of these gains, in particular by remaining vigilant and tackling any illegal sources of ozone-depleting substances as they arise.”
The ozone layer is the atmospheric shield that is situated in the stratosphere, which is around 9-18 miles above the Earth’s surface.
The ozone layer absorbs ultraviolet (UV) radiation from the sun, especially UVB rays. These UVB rays have been linked to the development of skin cancers and cataracts, while also being shown to cause damage to plant and marine environments.
The concentrations of ozone in the stratosphere will naturally fluctuate depending on the seasons and the latitude. The concentrations were stable in 1957 when the global measurements began.
However, research in the 1970s and 80’s identified that the ozone layer was under threat.
In 1974, research identified chlorofluorocarbon (CFC) gases as a threat to the ozone layer. When the CFCs reached the stratosphere they were broken down, by the sun’s UV rays, into substances including chlorine. The chlorine atom can destroy high numbers of ozone molecules, thus depleting the ozone layer. At the time, CFCs were common in aerosols and refrigerators as coolants.
A team of English scientists, in 1985, found a ‘hole’ in the ozone layer over Antarctica- that would later be linked to CFCs. The ‘hole’ is an area where there are very low concentrations of ozone in the stratosphere.
The identification of the detrimental effects of CFCs and other ozone-depleting substances resulted in the Montreal Protocol in 1987. The protocol was a landmark multilateral environmental agreement, that regulated the production and consumption of these ozone-depleting substances. The Montreal Protocol on Substances that Deplete the Ozone Layer is, to date, the only UN treaty to be ratified by every nation on Earth- all the 197 UN Member States.
The landmark protocol has resulted in the phase-out of 99% of ozone-depleting chemicals, that were in refrigerators, air-conditioning and other products.
Latest reports completed in 2018, showed parts of the ozone layer have recovered at a rate of 1-3% per decade, since 2000. Additionally, the protection efforts have helped with the fight against climate change by preventing an estimated 135 billion tonnes of carbon dioxide equivalent emissions, from 1990 to 2010.
The Kigali Amendment to the Montreal Protocol, which entered into force at the start of the year, promotes the phasing down of hydrofluorocarbons (HFCs). This amendment is expected to protect the ozone layer and avoid up to 0.4oC of global temperature rise by the end of the century.
The UN’s Secretary-General, António Guterres, in a statement showed support for the Kigali Amendment and encouraged all other nations to ratify the Amendment, as currently, only 81 nations have ratified it.
He also said: “A healthy ozone layer and climate are essential to meeting all of the Sustainable Development Goals. The Montreal Protocol continues to protect people and planet alike. Let this International Day for the Preservation of the Ozone Layer be an inspiration towards greater ambition on cooling, at the Climate Action Summit and beyond.”