We’re all frustrated at the inability of governments to take necessary measures to tackle climate change. Drastic actions are needed, such as putting an end to fossil fuels and setting a price on carbon.
COP26 gave us hope for our future, but we are still far from where we need to be. We might feel that this ecological crisis is impossible to stop.
But in the midst of despair, we can reflect on how our determination in the recent past to improve our standard of living triggered what could have ended in a global catastrophe. Instead, the potential crisis was dealt with by bringing the world together.
In this video, we will introduce you to ozone depletion — which almost led to disaster — in an easy and interesting way. You’ll see that attaining ecological stability is achievable with knowledge and cooperation.
Forty years ago, scientists warned that a hole in the layer of ozone surrounding the earth could have serious effects on human health and the environment. This problem is being solved thanks to a global agreement to stop the use of ozone-depleting chemicals that damage the ozone layer. But now scientists are concerned that the substances used to replace these ozone-depleting chemicals are acting to trap heat inside the earth, exacerbating the greenhouse effect. Can policymakers protect the ozone layer while also helping prevent climate change?
What is the ozone layer and how was it damaged?
The ozone layer sits in the stratosphere between 15 km and 30 km above the earth. It absorbs most of the sun's ultraviolet radiation (UV-B), limiting the amount of this radiation that reaches the surface of the Earth. Because this radiation causes skin cancer and cataracts, the ozone layer plays an important role in protecting human health. It also prevents radiation damage to plants, animals, and materials.
In the 1970s, scientists noticed that the ozone layer was thinning. Researchers found evidence that linked the depletion of the ozone layer to the presence of chlorofluorocarbons (CFCs) and other halogen-source gases in the stratosphere. Ozone-depleting substances (ODS) are synthetic chemicals, which were used around the world in a wide range of industrial and consumer applications. The main uses of these substances were in refrigeration and air conditioning equipment and in fire extinguishers. Other important uses included aerosol propellants, solvents and blowing agents for insulation foams.
Protecting the ozone layer also protects the climate
The reduction in ozone-depleting substances has also had a beneficial side-effect. Ozone-depleting substances are also very potent greenhouse gases, contributing to the phenomenon as other substances widely known to have a greenhouse effect like carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Therefore, by reducing emissions of ozone-depleting substances, the Montreal Protocol has protected both the ozone layer and the climate at the same time.
The magnitude of this benefit is substantial. The reduction in ODS emissions expected as a result of compliance with the Montreal Protocol has been estimated globally at 10-12 giga-tonnes of CO2-equivalent between 1985 and 2010 (Velders et al. 2007). In contrast, the reduction target of greenhouse gas emissions under the Kyoto Protocol (assuming full compliance by all developed countries) is estimated at 1-2 giga-tonnes of CO2-equivalent on average per year between 2008 and 2012, compared to base-year emissions. The phasing out of climate-changing ODS under the Montreal Protocol has therefore avoided greenhouse gas emissions by an amount 5-6 times larger than the target of the Kyoto Protocol for 2008-2012.
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