Major climate change milestone reached as gases behind ozone hole are cut for first time

Scientists optimistic greenhouse gases can be tackled and hole in ozone layer can be repaired

The Jungfraujoch station, in Switzerland, is part of the high-altitude Integrated Carbon Observation System and measures greenhouse gases. Photo:
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A major milestone in the fight against climate change has been achieved as greenhouse gases, which were behind the hole in the ozone layer, have dropped for the first time.

Levels of harmful hydrochlorofluorocarbons (HCFCs), or greenhouse gases, which were developed as replacements for chlorofluorocarbons (CFCs), have reduced.

The international Montreal Protocol was agreed to in 1987 and aimed to introduce controls on the production and use of ozone-depleting substances (ODS), which were once widely used in the manufacture of hundreds of products, including refrigerators, aerosol sprays, foams and packaging.

While production of CFCs has been banned globally since 2010, HCFC production and usage is still being phased out.

A study, published in the Nature Climate Change journal on Tuesday, reveals reductions have been recorded for the first time. It is a significant development, author Luke Western, Marie Curie Research Fellow at the University of Bristol's School of Chemistry, told The National.

“This is a major milestone,” he said. “Our prediction is that it will continue to decrease. If this trend continues the ozone hole will recover in about 40 years' time.

“In terms of climate change this is very significant. The biggest message this shows is that environmental policies, like the Montreal Protocol, do work. It is the first time since monitoring began in the 1980s that we have seen a reduction.”

The international study, titled Global Reduction in Harmful Greenhouse Gases and Ozone-Depleting Substances: Success of Montreal Protocol Confirmed, shows the total amount of ozone-depleting chlorine contained in all HCFCs peaked in 2021.

Although the drop between 2021 and 2023 was less than 1 per cent, it still shows HCFC emissions are heading in the right direction.

“The results are very encouraging. They underscore the great importance of establishing and sticking to international protocols,” Dr Western said.

“Their production is currently being phased out globally, with a completion date slated for 2040. In turn, these HCFCs are being replaced by non-ozone-depleting hydrofluorocarbons (HFCs) and other compounds.

“By enforcing strict controls and promoting the adoption of ozone-friendly alternatives, the protocol has successfully curbed the release and levels of HCFCs into the atmosphere.

“Without the Montreal Protocol, this success would not have been possible, so it’s a resounding endorsement of multilateral commitments to combat stratospheric ozone depletion, with additional benefits in tackling human-induced climate change. It shows the success of international co-operation and the importance of it in tackling environmental issues.”

The results rely on high-precision measurements at globally distributed atmospheric observatories, using data from the Advanced Global Atmospheric Gases Experiment and the National Atmospheric and Oceanic Administration (NOAA).

“We use highly sensitive measurement techniques and thorough protocols to ensure the reliability of these observations,” said co-author Dr Martin Vollmer, an atmospheric scientist at the Swiss Federal Laboratories for Materials Science and Technology.

Co-author Dr Isaac Vimont, a research scientist at the NOAA in the US, said environmental monitoring is imperative.

“This study highlights the critical need to be vigilant and proactive in our environmental monitoring, ensuring other controlled ozone-depleting and greenhouse gases follow a similar trend which will help to protect the planet for future generations,” he said.

In December, Nasa launched a website,, that will soon monitor locations around the world that are producing greenhouse gases.

Nasa administrator Bill Nelson revealed the details at a Future Talks event at the Museum of the Future in Dubai and said the website would use data from Nasa satellites to track greenhouse gases, which become trapped in the Earth’s atmosphere and cause the planet to heat up.

Updated: June 11, 2024, 1:25 PM