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

The impact of Hydrochlorofluorocarbons (HCFCs) on Earth's energy balance and globally averaged chlorine content of ODS in the 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 declines 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.

Montreal Protocol

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).

HECS are non-ODS alternative to CFCs and HCFCs.

HFC's GWP is thousands of times more than CO²

Ozone and Ozone-Depletting Substances (ODS)

ODS are human-made chemicals containing chlorine and bromine (like Chlorofluorocarbons (CFCs), HCFC).

Stratospheric ozone (good Ozone) are found at 10-40 KM above Earth's surface, and protects Earth from UV radiation of Sun.

The ozone formed in the Troposphere is harmful and is called 'bad ozone'.

They can reach stratosphere where they undergo catalytic reactions, further leading to destruction of ozone.