Montreal Protocol effective in reducing emissions of Ozone-Depleting Substances (ODS): Study

Posted 14 Jun 2024

2 min read

Key highlights of study

Impact of Hydrochlorofluorocarbons (HCFCs) on Earth’s energy balance and globally averaged chlorine content of ODS in troposphere has decreased since 2021, five years earlier (2026) than expected.
- HCFCs are compounds containing carbon, hydrogen, chlorine and fluorine.
HCFC-22, most abundant HCFC, has declined significantly. Its Global Warming Potential (GWP) is thousands of times more than carbon dioxide (CO2).
- HCFC-22 is used as a refrigerant in air conditioners, cold storage, retail food refrigeration, etc.
Minor decline were observed in HCFC-141b, second most abundant HCFC.
- HCFC-141b is used as a blowing agent in production of rigid polyurethane foams.
- India has achieved complete phase-out of HCFC-141b under ODS (Regulation and Control) Amendment Rules, 2014.
  - This is in line with India’s commitment under Montreal Protocol for Substances that Deplete Ozone Layer.

Signed in 1987, it is a global treaty to eliminate production and use of ODS.
Implemented under Vienna Convention (adopted in 1985).
Kigali Amendment to Montreal Protocol was adopted in 2016 (and entered into force in 2019) to phase-down production and consumption of Hydrofluorocarbons (HFCs).
- HFCs are non-ODS alternative to CFCs and HCFCs. HFC’s GWP is thousands of times more than CO2.

ODS are human-made chemicals containing chlorine and bromine (like Chlorofluorocarbons (CFCs), HCFC).
- They can reach stratosphere where they undergo catalytic reactions, further leading to destruction of ozone.
Stratospheric ozone (good Ozone) are found at 10-40 KM above Earth's surface, and protects Earth from UV radiation of Sun.
Ozone formed in Troposphere is harmful and is called ‘bad ozone’.