Good news for climate change

Photo: NASA Ozone Hole Watch

False-color view of total ozone over the Antarctic pole. Purple and blue represent areas where there is the least ozone, yellows and reds where there is more ozone.

It is a hopeful sign. It is a scientific measurement of improvement in the atmosphere.

The improvement demonstrates governments can create and stick to an agreement that has a positive effect on global warming. It is years ahead of schedule and it all started in Montreal.

Let’s back up for a moment. In the 1980s, we noticed here was a growing hole in the ozone layer. That was a problem because ozone forms a barrier against UV radiation. Sometimes atmospheric ozone is referred to as “a layer of sunscreen.” Less ozone means higher rates of health problems like skin cancer and cataracts.

Why was the ozone missing? Ozone-depleting substances, such as chlorofluorocarbons (CFCs) rise into the stratosphere and release chlorine atoms which react with ozone. Where did the CFCs come from? They were chemicals commonly used to create aerosol sprays (think hairspray), foams, packing materials and refrigerants.

In 1987, countries got together in Montreal to stop the use of CFCs with the goal of slowing and reversing the hole in the ozone layer. They put together the “Montreal Protocol,” pledging to stop using CFCs by 2010. Initially CFCs were replaced with hydrochlorofluorocarbons (HCFCs) but then it was discovered HCFCs were powerful greenhouse gasses, with a global warming potential 2,000 times stronger than carbon dioxide.

Amendments were added to the protocol in 1992 and 1999 to phase out HCFCs. The Montreal Protocol was eventually signed by 197 countries—every country in the world.

People don’t replace their refrigerators every year. Even when you stop selling refrigerators with HCFCs there will still be HCFCs released from refrigerators that have already been sold. (That is one reason why it’s important to recycle your refrigerators.) However, scientists modelled the effect of the Montreal Protocol on the rise of HCFCs and predicted the chemical would start declining in the atmosphere in 2029.

So, here is the exciting news. HCFCs in the atmosphere have already started declining. It is likely they reached their peak in 2021. In a paper published in Nature Climate Change on June 11, Luke Western (and 20 co-authors) showed that according to two different measurements, HCFC peaked in 2021 and declined in 2022.

What made the Montreal Protocol so effective? The general public, aided by videos created by scientists, understood the concept of the hole in the ozone layer. The threat was clear—missing ozone would lead to a higher rate of skin cancer. The solution was clear, stop using CFCs (and later HCFCs).

The Montreal Protocol also had an effective funding program where money from developed nations was donated to developing nations so they could retool and switch refrigerants.

What kind of impact does the decline of HCFCs have on climate change? First, because HCFCs are powerful greenhouse gasses, it is important they are starting to decline. Second, while scientific evidence for global warming has been around for decades, people now feel the impact on their daily lives through warmer winters, heat waves, changes in rainfall (both droughts and increases in tropical storms) and increases in wildfires. If you need a video to convince you, I recommend this NASA climate spiral video.

Perhaps more critical is his demonstrates countries around the world are capable of identifying a problem (such as the hole in the ozone layer or global warming), come together to draft a treaty and then honour it, leading to a measurable decline. Now is the time to double down, pressuring countries and governments to sign and comply with the “Paris Agreement.” We can do this—we already have.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.