December 1, 2021

I, Science

The science magazine of Imperial College

Iona Twaddell compares the major environmental issue of the 1980s with climate change and asks if there are lessons to learn
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The hole in the ozone layer, 2010

“MASSIVE ozone hole will increase CANCER rates”, blares the Daily Mail. “No-zone!” screams the Sun. “What type of ozone hole are you?” asks Buzzfeed. We are in a parallel universe, a world in which humans are still destroying our atmosphere with ozone-depleting chemicals like CFCs (chlorofluorocarbons) from aerosols and fridges. Thirty years after British scientists made the almost unbelievable discovery that there was a hole in the ozone layer over the Antarctic, politicians still have not agreed to ban these chemicals.

Luckily, in our world we have what Kofi Annan, former UN secretary general, has called “Perhaps the single most successful international agreement to date”: the Montreal Protocol on Substances that Deplete the Ozone Layer. Signed in September 1987, it was the first UN treaty to be ratified by every UN member nation. In our world politicians would never avoid a treaty on atmosphere-destroying substances for thirty years when the evidence for their harm was clear… would they? So where’s the international treaty banning fossil fuels? Five months away from the UN climate change summit in Paris, can we learn anything from the success of the Montreal Protocol to develop an international climate change treaty?

Scientists have recently modelled what a Montreal Protocol-free parallel universe would look like now, and it demonstrates the potential of international agreements. Assuming the concentration of ozone-depleting chemicals had continued increasing at 3% per year, an ozone hole over the Arctic would have joined the Antarctic one, and 14% more UV radiation would be reaching the UK. As Professor Martyn Chipperfield of the University of Leeds, lead author of the study says, “What surprised us was how quickly the large numbers appeared… It shows that the Montreal Protocol would have had a really significant benefit by now… it’s not a distant benefit.”

This has tangible impacts on human health. Ozone is the Earth’s sunscreen, absorbing the harmful UVB radiation that can cause skin cancer. The US Environmental Protection Agency has estimated that the Montreal Protocol will eventually prevent 1.5 million deaths from skin cancer in the US alone. Additionally, because CFCs are powerful greenhouse gases, by almost completely eliminating them, the Montreal Protocol may have been more effective at combatting climate change than actual climate treaties like the Kyoto Protocol.

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Air conditioning units

So what is the difference between the ozone problem and the climate change problem? One obvious difference is that our whole world runs on fossil fuel fumes, backed by powerful companies and countries, whereas CFCs were only used in niche, relatively weak, industries. And there was already an alternative to CFCs, HFCs (hydrofluorocarbons). This made it a “perfect case for technological fix” according to Dr Hannes Stephan, an environmental politics researcher at the University of Stirling. The relative failure of renewables means there is currently no technological fix for fossil fuels.

Dr Stephan also notes that the world was different when the Montreal Protocol was signed: “Importantly the US was still very much the uncontested Western superpower… so when the US swung behind it, it became much easier to find a consensus with the main players, and of course the main players were fewer in number.” And the US only really supported the Montreal Protocol once a US chemical firm, Dupont, had invented HFCs and they could make money from the transition. Perhaps if the US oil and gas industries find an alternative for fossil fuels, we’ll get a climate change treaty.

But even the Montreal Protocol is not perfect. While HFCs (the replacement for around 15% of ozone-depleting substances) do not damage ozone, they are powerful greenhouse gases. The Montreal Protocol allows for amendments (of which there have been eight), but adding HFCs to the list of banned substances would steer the protocol into climate change territory, with the associated baggage. Nevertheless this amendment has support from backers including the US, the EU and India so there is hope. Perhaps more worryingly, some ozone-depleting chemicals have started re-appearing in the atmosphere. We have to hope they are just old stocks sold on the black market, rather than newly produced ones. And new threats are emerging. As Prof Chipperfield says, “Towards the end of the 21st century, the models suggest that the most important gas for depleting the ozone layer will be nitrous oxide.” The ozone layer is not completely safe yet.

Despite these problems, the ozone layer is still expected to recover by around 2060, thanks to the Montreal Protocol. It is unlikely that we’ll get an equivalent at this year’s UN climate change summit, but we have to hope that there will be a powerful international agreement soon so that in thirty years we’ll be talking about a parallel universe of natural disasters, famine and rising sea levels, and not living in it.

Iona Twaddell is studying for an MSc in Science Communication

Images: Snapshot of the Antarctic Ozone Hole 2010 by NASA Goddard Space Flight CenterAC units are out by Pierre (Flickr; Creative Commons)

Citation: Chipperfield, M. P. et al. (2015) Quantifying the ozone and ultraviolet benefits already achieved by the Montreal Protocol. Nature Communications 6, Article number: 7233 doi:10.1038/ncomms8233