Good News About Ozone and Climate Change
Great news! Fixing atmospheric ozone to protect life from harmful ultraviolet rays has helped decrease greenhouse gases that cause climate change, and we are 5 years ahead of schedule by one metric.
Ozone depletion in the stratosphere was a major threat to life on Earth, and the Montreal Protocol and subsequent amendments have gone a long way to averting disaster. For more information and background about the Montreal Protocol and its amendments that are closing the “ozone hole” (see our podcast episode 6 “How Diplomacy Closed the Ozone Hole” or listen on your favorite podcast platform. We also have a news brief on the progress that has been made).
Hydrochlorofluorocarbons (HCFCs) were part of the solution to preventing further stratospheric ozone depletion when they were used to replace chlorofluorocarbons (CFCs) that were much stronger ozone-depleting substances. But HCFCs are imperfect. In fact, HCFCs are powerful greenhouse gases and still deplete ozone, though much less so than CFCs. A phaseout of HCFCs was mandated to be completed by 2040.
An article published on June 11, 2024 in Nature Climate Change reported that: “The radiative forcing [the effect on global warming/climate change] from HCFCs in 2021 is around a fifth of that from CFCs at their peak.”
That is, replacing CFCS by HCFCs has had a major role in combatting climate change!
From the Nature Climate Change article:
“..the phaseout of consumption and production of long-lived CFCs, which have high global warming potentials, it has also avoided substantial global warming. The total direct radiative forcing due to CFCs in the atmosphere peaked in 2000.”
They go on to say the positive effect of these changes on climate change and ozone depletion has increased between 2021 and 2023. In fact, we are 5 years ahead of schedule in meeting the final target relative to previous HCFC projections!
This shows a point we have made before: the Montreal Protocol and its amendments for preserving the beneficial stratospheric ozone layer have been a major boon not only in protecting our biosphere from harmful ultraviolet radiation, but also in fighting climate change!
Great news, but still work to be done. HCFCs were replaced in part by hydrofluorocarbons (HFCs); they do not deplete ozone, but HFCs are not a perfect solution as they are about 2% of greenhouse gas emissions. But unlike CO2, which lasts many decades to centuries in the atmosphere, HFCs only last about 15 years in the atmosphere which means decreasing HFCs would have a positive effect in just a few years. And there has been movement to do so.
From the Nature article:
“The Kigali Amendment to the Montreal Protocol initiated controls on production and consumption of HFCs, which have widely replaced HCFCs for many applications. Additional commitments have been made to reduce emissions of HFCs under the Paris Agreement and the Global Cooling Pledge.”
The Kigali Amendment was accepted as an amendment to the Montreal Protocol in 2016 but it takes time to enact, in part due to politics. In the United States, for example, little movement was made under the Trump administration to join in, but the Kigali Amendment was finally ratified and signed by President Biden on October 26, 2022. We need to continue making progress.
We can get things done!
Thumbnail image of HFCF and Ozone (O3 the three red spheres) alamy stock photo