Hole in the sky: why it happened and how we tackled it

Sri Lanka is still struggling with a confusing political and economic crisis. Which way and where we will go is given different interpretations by political leaders and economic experts in such a crisis within a crisis, we are giving little attention to the preservation of the ozone layer—a vital factor that could affect the whole world. 

On September 16, the United Nations marks the International Day for the Preservation of the Ozone Layer. In a statement, the UN says The ozone layer, a fragile shield of gas, protects the Earth from the harmful portion of the rays of the sun, thus helping preserve life on the planet. The phaseout of controlled uses of ozone-depleting substances and the related reductions have not only helped protect the ozone layer for this and future generations but have also contributed significantly to global efforts to address climate change; furthermore, it has protected human health and ecosystems by limiting the harmful ultraviolet radiation from reaching the Earth.

 
Referring to the Montreal Protocol for global cooperation for the protection of life on earth, the UN says as the treaty turns 35 on Ozone Day, we will remember how the Montreal Protocol ended one of the biggest threats ever to face humanity as a whole: the depletion of the ozone layer. When the world found out that ozone-depleting gases used in aerosols and cooling were creating a hole in the sky, they came together. They showed that multilateralism and effective global cooperation worked and they phased out these gases. Now the ozone layer is healing, allowing it once again to shield humanity from the sun’s ultraviolet radiation.

 
According to the UN, a number of commonly used chemicals have been found to be extremely damaging to the ozone layer. Halocarbons are chemicals in which one or more carbon atoms are linked to one or more halogen atoms (fluorine, chlorine, bromine or iodine). Halocarbons containing bromine usually have much higher ozone-depleting potential (ODP) than those containing chlorine. The human-made chemicals that have provided most of the chlorine and bromine for ozone depletion are methyl bromide, methyl chloroform, carbon tetrachloride and families of chemicals known as halons, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). 
Focusing on the Vienna Convention for the Protection of Ozone Layer, the UN says the scientific confirmation of the depletion of the ozone layer prompted the international community to establish a mechanism for cooperation to take action to protect the ozone layer. This was formalized in the Vienna Convention for the Protection of the Ozone Layer. This was adopted and signed by 28 countries, on  March 22, 1985. In September 1987, this led to the drafting of The Montreal Protocol on Substances that Deplete the Ozone Layer. 
Implementation of the Montreal Protocol progressed well in developed and developing countries. All phase-out schedules were adhered to in most cases, some even ahead of schedule. Attention focused initially on chemicals with higher ozone-depletion potentials, including CFCs and halons. The phase-out schedule for HCFCs was more relaxed due to their lower ozone-depletion potentials and because they have also been used as transitional substitutes for CFCs. 

The HCFC phase-out schedule was introduced in 1992 for developed and developing countries, the latter with a freeze in 2015, and the final phase-out by 2030 in developed countries and 2040 in developing countries. In 2007, Parties to the Montreal Protocol decided to accelerate the HCFC phase-out schedule for both developed and developing countries. 
On September 16, 2009, the Vienna Convention and the Montreal Protocol became the first treaties in the history of the United Nations to achieve universal ratification. 
The Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer reached an agreement at their 28th Meeting of the Parties on October 15, 2016 at Kigali in Rwanda to phase down hydrofluorocarbons (HFCs). 
To mark the event, the UN Secretary-General Antonio Guterres says The Montreal Protocol and the Kigali Amendment show us that by acting together, anything is possible. So let us act now to slow climate change, feed the world’s hungry and protect the planet that we all depend on. 
Germany’s widely respected former Chancellor Angela Merkel has said climate change knows no borders. It will not stop before the Pacific islands and the whole of the international community here has to shoulder a responsibility to bring about a sustainable development.