Recent data show significant reductions in hydrochlorofluorocarbons (HCFCs), which are harmful to both the ozone layer and the climate. This achievement, a result of the Montreal Protocol, shows that global efforts to phase out these substances are working, and that reductions are exceeding previous estimates.

A new study by an international team of researchers has made significant progress in efforts to reduce atmospheric levels of chemicals that destroy the world’s protective ozone layer, confirming the success of historic regulations limiting their production and use. Empa scientists contributed to this research through measurements at the high-altitude research station in Jungfraujoch.

Montreal Protocol and HCFC

A recently published study conducted by researchers at the University of Bristol Nature Climate ChangeFor the first time, there has been a significant reduction in atmospheric levels of powerful ozone depleting substances (ODS) called hydrochlorofluorocarbons (HCFCs). These HCFCs are also harmful greenhouse gases (GHGs), so reducing them will also reduce global warming.

The Montreal Protocol was adopted internationally in 1987 to implement controls on the production and use of ODS, which were once widely used in hundreds of products including refrigerators, aerosol sprays, foams and packaging. HCFCs were developed to replace chlorofluorocarbons (CFCs). Although the production of CFCs has been banned worldwide since 2010, the production and use of HCFCs is currently being phased out worldwide, with a planned phase-out date of 2040. They will be replaced by hydrofluorocarbons (HFCs) and other compounds that do not destroy the ozone layer.

“The results are very encouraging. They highlight the importance of establishing and following international protocols,” says lead author Luke Western, from the School of Chemistry at the University of Bristol. “This achievement would not have been possible without the Montreal Protocol. As such, it is a strong endorsement of multilateral commitments to combat stratospheric ozone depletion, with the added benefit of combating human-induced climate change.”

The decline is faster than expected

An international study shows that the total amount of ozone-depleting chlorine found in all HCFCs will peak in 2021. These compounds are also potent greenhouse gases, so their contribution to climate change also peaked this year. This peak occurred five years earlier than predicted in the last Ozone Assessment Report, published in 2022. Although the decrease between 2021 and 2023 is less than 1%, it still shows that HCFC emissions are moving in the right direction.

According to Empa scientist and co-author Stephan Reimann, this study “represents an important milestone in the history of measures to reduce the ozone hole, as we were able to show for the first time that even substitutes for the ozone layer cause even greater damage. We are now reducing the CFV and that is five years earlier than expected.” According to the Empa researcher, this was only possible thanks to the continuous strengthening of international protocols and their verification through atmospheric measurements, for example in the Jungfraujoch.

Ensuring future environmental stability

The results are based on high-precision measurements at atmospheric observatories distributed around the world, using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) in the USA and the National Atmospheric and Oceanic Administration (NOAA), including the high-altitude research station at Jungfraujoch, where the Empa scientists carried out the atmospheric measurements.

“We use highly precise measurement techniques and careful protocols to ensure the reliability of these observations,” said co-author Martin Vollmer, an atmospheric scientist at Empa.

Co-author and NOAA scientist Isaac Vimont added: “This study underscores the critical importance of being vigilant and proactive in our environmental monitoring, ensuring that other controlled ozone-depleting and greenhouse gases follow a similar trend that will help protect the planet for future generations.”