In 1987, the Montreal Protocol banned the use of ozone-depleting chemicals across the globe. It came into effect on September 15th 1987, and remains the only UN treaty that has been ratified by every country in the world – 198 UN states. A new study has found that, if not outlawed, these chemicals would have caused a 2.5 degrees Celsius rise of extra global warming by 2100.
The landmark environmental agreement, named: The Montreal Protocol on Substances that Deplete the Ozone Layer, regulates the production and use of approximately 100 man-made chemicals which are referred to as Ozone depleting substances (ODS).
Those chemicals were identified as damaging to the stratospheric Ozone layer, which protects the globe and all of its organisms, due to harmful levels of ultraviolet radiation from the sun, causing global temperatures to rise.
The globe is already facing the catastrophic consequences of global rising temperatures, and governments, companies and individuals across the world are being urged to do more to cut carbon emissions and combat the current climate crisis.
An international team of scientists have found, however, that the continued use of chemicals such as chlorofluorocarbons (CFCs), banned in the Montreal Protocol, would have contributed to temperatures rising by an additional 2.5 degrees Celsius by the end of the century.
The researchers estimated that the use of CFCs could raise global temperatures to approximately 3.5 degrees Celsius by 2100. CFCs could be used in refrigerators, insulation foams and aerosols. The study found that the ongoing depletion of the ozone caused by CFCs and greenhouse gasses would have drastically compromised Earth’s ability to absorb CO2 from the atmosphere.
Former UN Secretary General Kofi Annan said that the agreement was “perhaps the single most successful international agreement”.
The ozone layer shields the earth and its flora from damaging UV rays. Increasing a plant’s exposure to UV can damage its tissues, restricting growth and limiting its ability to photosynthesise. Photosynthesis allows vegetation to pull CO2 from the atmosphere. CO2 is a toxic planet heating greenhouse gas, and the damage to plants would have also released additional CO2 currently stored in healthy vegetation.
Speaking to The Guardian, lead researcher in the study, Dr Paul Young, said: “a world where these chemicals increased and continued to strip away at our protective ozone layer would have been catastrophic for human health, but also for vegetation… with our research, we can see that the Montreal protocol’s successes extend beyond protecting humanity from increased UV to protecting the ability of plants and trees to absorb CO2.”
“Although we can hope that we never would have reached the catastrophic world as we simulated, it does remind us of the importance of continuing to protect the ozone layer… Entirely conceivable threats to it still exist, such as from unregulated use of CFCs.”
Not only are CFCs damaging to the Ozone layer, they are also a greenhouse gas themselves. According to the BBC, “The scientists estimated there would be: 580 billion tonnes less carbon stored in forests, other vegetation and soils and an extra 165-215 parts per million (40-50%) of carbon dioxide in the atmosphere.”
The study doesn’t indicate that we have successfully beat climate change, just avoided further damage. There is still much more to be done when it comes to combating the climate crisis.
The Earth has already warmed between 1.1 and 1.2 degrees Celsius above pre-industrial levels. The Paris Climate Agreement aims to limit that warming to 1.5 degrees Celsius and keep it well below 2 degrees Celsius – to prevent the cataclysmic impact and irreversible damage this increase would have on the world. To do this, governments across the world are urged to drastically cut their greenhouse gas emissions among other actions.
A report from NASA, entitled Why Global Temperatures Matter, examined the IPCC special report on climate change, and detailed the chain of events that global warming has, from the impact on wildlife, ecosystems to human survival. It explained: ‘at 1.5 degrees Celsius warming, the report projects that climate-related risks to human health, livelihoods, food security, human security, water supply and economic growth will all increase, and will increase even more at 2 degrees warming.’
Lead researcher in the study Dr Paul Young, of the Lancaster Environment Centre said to BBC Radio 4’s Inside Science program:
“What we see in our ‘world-avoided experiment’ is an additional 2.5C warming above any warming that we would get from greenhouse-gas increases… The science was listened to and acted upon – we have not seen that to the same degree with climate change.”
However, he also noted “But I would be cautious of using it as a positive example for the climate negotiations… It’s not [directly] comparable – but it’s nice to have something positive to hold on to and to see that the world can come together.”