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Source: The post is based on an article “Ozone hole, filling up now: What this means for climate action” published in The Indian Express on 11th January 2023.
Syllabus: GS 3 – Climate Change
Relevance: recovery of ozone
News: An UN-based report suggests that the ozone hole of the world is expected to be completely repaired by 2066.
How did the recovery of the ozone hole happen?
It happened due to the successful elimination of Ozone Depleting Substances (ODSs), through the implementation of the Montreal Protocol of 1989.
As per the report, 99 percent of the substances banned by the Montreal Protocol have been eliminated from use resulting in a recovery of the ozone layer.
What is ozone and what are the reasons behind its depletion?
Ozone, a molecule having three Oxygen atoms (O3) is found mainly in the stratosphere. It absorbs ultraviolet rays coming from the Sun.Ozone hole, filling up now: What this means for climate action Ozone hole refers to the reduction in concentration of the ozone molecules.
In the 1980s, scientists began to notice a sharp drop in the concentration of ozone because of the use of chlorofluorocarbons (CFCs) that were used extensively in the air conditioning, refrigeration, paints, and furniture industries.
What were the key findings of the UN based assessment?
As per the assessment, if current policies continued to be implemented, the ozone layer was expected to recover to 1980 values by 2066 over Antarctica, by 2045 over the Arctic, and by 2040 for the rest of the world.
Moreover, ozone-depleting substances are greenhouse gases which are more dangerous than carbon dioxide.
Therefore, the effective implementation of Montreal Protocol and elimination of ODSs would ensure the avoidance of 0.5 to 1 degree Celsius of warming by 2050.
Hence, with these views the Montreal Protocol was amended in 2016 to extend its mandate over hydrofluorocarbons (HFCs) that have replaced the CFCs in industrial use.
What are HFCs and what are the amendment made in the Montreal Protocol?
HFCs do not cause much damage to the ozone layer but are very powerful greenhouse gases.
The Kigali Amendment to the Montreal Protocol seeks to eliminate 80-90 percent of the HFCs currently in use by the year 2050. This is expected to prevent another 0.3 to 0.5 degree Celsius of global warming by the end of the century.
Moreover, the success of Montreal Protocol is often cited as an example to curtail the other greenhouse gases. However, it might not be possible.
Why other greenhouse gases cannot be curtailed like ODSs?
ODSs are not widely emitted and hence their limitation was successful but the emission of carbon dioxide is linked to the harnessing of energy. Almost every economic activity leads to carbon dioxide emissions.
For example, renewable energies have considerable carbon footprints because their manufacturing, transport, and operation involves the use of fossil fuels.
Further, unlike ODSs which were limited to the specific industry, greenhouse gas emissions are not limited to a few industries or economic sectors, but affects the entire economy.