A new study released in the journal Nature Climate Change reported the first significant decrease in atmospheric concentrations of potent ozone-depleting substances (ODS) known as hydrochlorofluorocarbons (HCFCs).
- This reduction has occurred five years before the target year, signifying a crucial step forward in efforts to mend the ozone layer.
- HCFC emissions peaked in 2021, five years sooner than the anticipated year 2026 and are heading in the right direction.
- The impact of HCFCs on the Earth’s energy balance (known as radiative forcing) and the amount of chlorine from these gases in the atmosphere (called equivalent effective chlorine) have decreased since 2021 five years earlier than expected.
- HCFCs trap heat in the Earth’s atmosphere and have an impact on climate and radiative forcing. A drop in levels leads to a smaller impact on the warming of the planet.
- HCFC-22, the most abundant HCFC, has witnessed the most significant decline. HCFC-22, has a global warming potential 1,910 times that of carbon dioxide on a 100 year time horizon. HCFC-22 is used as a refrigerant in a variety of applications, including unitary air conditioners, cold storage, retail food refrigeration, chillers, and industrial process refrigeration.
- A minor decline was also observed in HCFC-141b, the second most prevalent, from 24.63 ppt in 2022 to 24.51 ppt in 2023.
- Since 2017, the third most prevalent, HCFC-142b, has been progressively declining.
- In India, the issuance of import license for HCFC-141b is prohibited from 1st January, 2020 under Ozone Depleting Substances (Regulation and Control) Amendment Rules, 2019 issued under the Environment (Protection) Act, 1986.
- HCFC-141b is not produced in India and all the domestic requirements are met through imports. With this notification, prohibiting the import of HCFC-141 b, the country has completely phased out the important ozone depleting chemical.
- The Montreal Protocol, signed in 1987, is a global agreement to protect the stratospheric ozone layer by eliminating the production and consumption of ODSs like chlorofluorocarbons (CFCs).
- The worldwide production of CFCs has been prohibited since 2010. In order to replace CFCs, HCFCs were produced. However, they are also strong greenhouse gases and ODSs. Therefore, the Copenhagen (1992) and Beijing (1999) Amendments to the Montreal Protocol mandated the phase-out of HCFC production and usage.
- Since then, hydrofluorocarbons (HFC) have become available as a substitute for HCFCs. HFCs have largely replaced HCFCs for many purposes and restrictions on their manufacture and consumption were introduced by the Kigali Amendment in 2016 to the Montreal Protocol.
