The Current

'Somebody was violating the protocol': How nations tackled a renewed threat to the ozone layer

In an effort to reduce carbon emissions, the 1987 Montreal Protocol banned the use of chlorofluorocarbons. Although the hole over Antarctica is healing, an increase to in emissions has some scientists worried.

New study projects ozone hole to slowly recover in the next 43 years

The aurora australis is seen near the South Pole Atmospheric Research Observatory in Antarctica. When a hole in the ozone formed over Antarctica, countries around the world in 1987 agreed to phase out several types of ozone-depleting chemicals called chlorofluorocarbons (CFCs). (Patrick Cullis/NOAA via Associated Press)

When the Montreal Protocol was signed in 1987, it was a significant international effort to help protect and repair the ozone layer. 

The protocol banned the use of chlorofluorocarbons (CFCs) — a type of greenhouse gas that contributes to ozone depletion. 

Before that, CFCs were used in "large quantities," in products like cleaning agents and aerosol sprays, according to Stephen Montzka, a scientist with the U.S. National Oceanic and Atmospheric Administration. 

According to a new report by the United Nations, the hole over Antarctica is slowly but noticeably healing, and should be fully mended in about 43 years.

Montzka says banning them was "essential" to help the ozone layer's gradual recovery. But recently, an increase in emissions might point to a violation of that ban in recent years. 

Here is part of Montzka's conversation with The Current's host Matt Galloway. 

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I want to talk about what's happening now, but let's go back just briefly to the 1980s. I'm old enough to remember when news of the hole in the ozone was seen as some sort of threat to humanity, an existential crisis that we as a planet had to come to deal with. Remind us how this happened and what the CFCs were being used for.

CFCs were being used in large quantities for different applications, such as refrigeration, as foam blowing agents for insulating foams for solvents, cleaning agents, aerosol sprays, things like that. And so their use as a result of industrial production was allowing elevated concentrations of these gasses to build up in the atmosphere.

And as a result, their concentrations were reaching the stratosphere and facilitating the degradation, the catalytic destruction of ozone in the stratosphere and causing increased levels of UV radiation.

False colour image of the planet earth, with a big blue section showing the ozone layer hole.
In this NASA false-color image, the blue and purple shows the hole in Earth's protective ozone layer over Antarctica on Oct. 5, 2022. Earth’s protective ozone layer is slowly but noticeably healing at a pace that would fully mend the hole over Antarctica in about 43 years, a new United Nations report says. (NASA via The Associated Press)

How significant was the Montreal Protocol in helping to eliminate them?

That was essential. Otherwise it wouldn't have happened, I don't think.

Well, the issue, though, was that they didn't just disappear. As I mentioned in 2010, CFCs were banned, but scientists began to see a creep up in those levels again. What was going on there?

We saw, most directly following the [signing of the] protocol, dramatic declines in production and in emissions, and within a few years, concentrations of ozone-depleting gasses. It's clear that the protocol was succeeding in achieving its goal to reduce the concentration of these gasses that would ultimately allow for recovery of the ozone layer.

2010 was the year that CFC production was essentially banned globally, and it was three or four years after that that we started seeing, from the measurements that we're making at remote sites around the world, emissions of CFC-11, the second-most abundant CFC, increasing in the atmosphere.

And through a lot of careful and tedious work, we were able to determine that it meant that it was likely that somebody was violating the protocol a number of years after that ban. 

Who was it that was violating the protocol?

It was probably some country in eastern Asia. And subsequent to that initial report that we led, measurements in Eastern Asia … were able to determine that a large fraction of the emission increase was coming from eastern China.

What was the reaction from the international community? How did the world come together to try to address this again? 

I think the reaction of the international community was like mine: it was astounding surprise. And with regard to the unexpected nature of this and the significance of it, the parties to the Montreal Protocol every year since the mid-1980s have met twice a year to assess the state of the science of ozone depletion, to understand whether or not their controls should be strengthened or weakened.

And after we first reported this apparent violation of the protocol, [we] took a primary role in the meetings of the parties to the protocol for the next few years. 

A series of satellite images from 1980 to 2001 showing the hole in the ozone layer.
Images of the hole in the ozone layer above Antarctica, seen in a series of satellite images over a 21-year time span, from 1980 to 2001. (STR New/Reuters)

This week, these assessments of CFC levels came out. And as I mentioned, the sense is that the hole in the ozone layer is on its way to being healed. Is that fair to say?

That is fair to say. And that's been true. And fortunately, I think the fact that we have an atmospheric science community in place to monitor changes allows us to provide an early warning when things are changing as expected.

So the concentrations have been declining of ozone-depleting gasses since the 1990s, and that gradual decline continues. It continued even though there was this slight blip in emissions of CFC-11. And so the path for recovery still looks clear to be within the next few decades. 

What does that tell you about the power of international cooperation — when the world is facing a crisis like this, that if people in nations can put their minds together, that there is a way forward? What does it tell you?

That it can be successful, given the impetus, given the desire. And if the issue is severe enough so that all of us can really feel that it is one that needs to be taken care of, we can do it. 

If we take a look at the climate crisis broadly right now, what could we learn from what happened when it came to the issue of the ozone layer? … What should we learn from that to apply to the climate crisis?

I think that there's a number of things. One, that we can be successful. Two, that you don't need to solve the problem right away. The Montreal Protocol initially wouldn't have solved the problem, but it got parties together talking with each other to understand their concerns.

And ultimately, that led to strengthening of the protocol so that it could solve the problem — revisiting regularly with the parties and providing input from the scientists to understand the state of the science and how it changes over time and whether or not policy needs to be adjusted as a result.

And there are issues also related to how you include less developed countries, so that their needs can be addressed. And so they're under-resourced activities can be accounted for, and they can be brought on board. 


Keena Alwahaidi is a reporter and associate producer for CBC. She's interested in news, arts/culture and human interest stories. Follow her on Twitter at @keenaalwahaidi

With files from The Associated Press.

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