Context:
According to a recent study done by scientists at Bristol University (England), there has been a significant decline in the atmospheric concentration of harmful ozone-depleting substances, specifically hydrochlorofluorocarbons (HCFCs).
Key Findings of the Study
- The decrease in HCFC concentration has occurred five years earlier than the target year, thus marking a significant advancement in repairing the ozone layer.
According to the study, HCFC emissions peaked in 2021, five years sooner than the anticipated year 2026. - The study revealed that the impact of HCFCs on the Earth’s energy balance (known as radiative forcing) and atmospheric chlorine levels (called equivalent effective chlorine) has been decreasing since 2021.
In 2022 and 2023, both the global radiative forcing and equivalent effective chlorine (EECl) from HCFCs decreased.
- In 2023, the global radiative forcing from HCFCs dropped to 61.28 milliWatt per square meter from 61.67 milliWatt per square meter.
- In the same period, the equivalent effective chlorine decreased from 321.35 to 319.33 parts per trillion (ppt).
The decline was most pronounced in the northern hemisphere, mainly due to changes in emissions, with HCFC-22 experiencing the most significant decrease.
- HCFC-22 has a global warming potential 1,910 times higher than carbon dioxide over a 100-year period.
HCFC-141b (second most prevalent HCFC) also saw a minor decline, while HCFC-142b (third most prevalent HCFC) has been steadily decreasing since 2017.
- The HCFCs will return to their 1980 values in 2082 for radiative forcing and in 2087 for the EECI.
Montreal protocol’s contributions in declining HCFC levels
- The Montreal Protocol, signed in 1987, aims to safeguard the ozone layer by banning the production and use of ozone-depleting substances (ODSs) like chlorofluorocarbons (CFCs).
- CFC production has been banned globally since 2010.
- Hydrochlorofluorocarbons (HCFCs) were introduced as substitutes for CFCs but are also potent greenhouse gases and ODSs.
- Consequently, the Copenhagen (1992) and Beijing (1999) Amendments to the Montreal Protocol mandated the phase-out of HCFCs.
Since then, Hydrofluorocarbons (HFCs) have emerged as alternatives to HCFCs. - The global phase-out of HCFC production is underway, scheduled for completion by 2040.
- The research paper highlights the significance of global agreements like the Montreal Protocol and its amendments in reducing HCFC emissions.
- The Kigali Amendment, added to the Montreal Protocol in 2016, imposed strict limits on the production and use of HFCs, which have largely replaced HCFCs in many applications.
- Commitments to reduce HFC emissions have also been made under initiatives like the Global Cooling Pledge and the Paris Agreement.