A Harmful Gas for the Ozone Layer is Declining Earlier Than Expected

Hydrochlorofluorocarbons (HCFCs)

began to decline after peaking in 2021, according to a study published Tuesday in the journal "Nature Climate Change." This decline, occurring five years earlier than anticipated, is attributed to the success of the

Montreal Protocol.

International Commitment to Protect the Ozone Layer

International commitments to protect the ozone layer are bearing fruit as the atmospheric concentrations of a family of harmful gases, hydrochlorofluorocarbons (HCFCs), have begun to decline faster than expected. This information comes from a study published on Tuesday, June 11. "This is a success, and it makes one optimistic that climate and environmental treaties can work," said Luke Western of the University of Bristol, the lead author of the study.

The Montreal Protocol: A Global Effort

The Montreal Protocol, signed in 1987, represents an international commitment to gradually eliminate substances that deplete the ozone layer. These substances have been used extensively in refrigeration, air conditioning, foam blowing, and aerosols. Initially, the Protocol aimed to eliminate chlorofluorocarbons (CFCs), which were subsequently replaced by hydrochlorofluorocarbons (HCFCs). These HCFCs, while less harmful than CFCs, are still detrimental to the ozone layer.

Impact of HCFCs

Hydrochlorofluorocarbons are present in various applications, such as air conditioners, refrigerators, and car cooling systems. These gases are very effective at absorbing heat and producing cold but are harmful to the ozone layer that protects us from UV rays. Additionally, they are powerful greenhouse gases contributing to global warming.

Decline of HCFCs: Earlier than Expected

Their production and use are still being phased out, but the international team behind the study has shown that the level of ozone-depleting chlorine from HCFCs had already peaked in 2021, five years earlier than previously expected. The researchers based their findings on measurements from a network of specialized monitoring stations known as “Advanced Global Atmospheric Gases Experiment” and data from the U.S. National Oceanic and Atmospheric Administration.

Visualizing the Change

A graph from the study shows black lines representing a return to 1980s levels by the end of the 2080s. This visualization underscores the significant progress being made in reducing harmful emissions and protecting the ozone layer.

Success of the Montreal Protocol

"By implementing strict controls and promoting ozone-friendly alternatives, the protocol has managed to curb HCFC emissions and levels in the atmosphere," said Luke Western. "Without the Montreal Protocol, this success would not have been possible, so it's a spectacular validation of multilateral commitments to combat the loss of the stratospheric ozone layer, with additional benefits in the fight against human-caused climate change."

A Model for Environmental Action

The protection of the ozone layer is regularly cited by scientists as an example of successful collective action for the environment. According to the latest four-year assessment by the United Nations Environment Programme, published in early 2023, the ozone layer is expected to "replenish within the next four decades." This optimistic outlook highlights the effectiveness of international cooperation and policy implementation in addressing global environmental challenges.