World Ozone Day

Context

A recent study finds black carbon due to frequent, widespread wildfires may be widening the ozone hole.

About

Key findings of the study:

The wildfires that scorched much of Australia between June 2019 and March 2020 were unprecedented in scale and nature.
- The fires have also triggered changes kilometres high in the atmosphere, widening the ozone hole.
- The intense and uncontrolled fires resulted in millions of tonnes of smoke and associated gases.
The smoke plumes formed several vortices, the largest of which maintained a coherent and isolated structure for over two months and was eventually detected at altitudes of up to 36 km.
The smoke plumes rose to such great heights because of black carbon, which absorbs solar heat and rises into the lower stratosphere like a hot-air balloon.
- The ozone layer sits in the stratosphere, located between 10 km and 50 km above Earth's surface, and absorbs harmful ultraviolet radiation from the sun.
Once in the stratosphere, black carbon continues to absorb sunlight and warm the air. The 2019-20 wildfires spiked temperatures in the lower stratosphere over Australia by 3 degrees Celsius, globally the temperatures rose by 0.7°C.
Rising global temperatures and drier conditions are leading to frequent, massive wildfires around the world, according to the UN Intergovernmental Panel on Climate Change.
The frequency of extreme wildfires will likely rise by 30 per cent by 2050, according to the United Nations Environment Programme. Such events could undo 35 years of efforts under the Montreal Protocol.

World Ozone Day

September 16 of each year is observed as World Ozone Day, also known as the International Day for the Preservation of the Ozone Layer.
World Ozone Day is celebrated to draw attention to one of the biggest threats that humanity faces, the depletion of the ozone layer, and the dangers of ozone depletion.
The purpose of the day is to raise awareness about the importance of preserving the ozone layer.
This 2022 marks the 35th year of implementation of the Montreal Protocol, UN is observing the Ozone Day with the theme "Montreal Protocol@35" and the worldwide collaboration safeguarding life on earth is the topic for this year's World Ozone Day.

Ozone layer

Ozone layer is a fragile shield of gas which protects the Earth by absorbing harmful ultraviolet (UV) radiation of Sun and thus helps preserve life on the planet.
Stratospheric ozone is not harmful, but its presence in troposphere is harmful.
Substances like Chlorofluorocarbons, Halons, Carbon-tetrachloride are considered as Ozone Depleting Substances (ODSs)
Dobson unit is a unit which is used to measure the ozone in the atmosphere at a standard temperature and pressure.

Montreal Protocol

It is an international treaty agreed in 1987 in Montreal, Canada and entered into force on 26 August 1989
It is designed to protect ozone layer by phasing out production of numerous ODSs that are responsible for ozone depletion.
With Kigali amendment, it plans to reduce the manufacture and use of Hydrofluorocarbons (HFCs) by roughly 80-85% from their respective baselines till 2045.
It is legally binding on member countries.
It has been ratified by 197 parties making it universally ratified protocol in UN history.
It is termed as highly successful international arrangement, as it has phased-out more than 95% of the ODS so far. It has also helped in recovering the ozone hole in Antarctica.

Vienna Convention for Protection of the Ozone Layer

It is a multilateral environmental agreement agreed upon at the 1985 Vienna Conference and entered into force in 1988.
It acted as framework for international efforts to protect fragile ozone layer. These are laid out in accompanying Montreal Protocol.
However, it does not include legally binding reduction goals for the use of CFCs, the main chemical agents causing ozone depletion.
It is also one of the most successful treaties of all time in terms of universality and has been ratified by 197 states.