A number of commonly used chemicals have been found to be extremely damaging to the ozone layer. Halocarbons are chemicals in which one or more carbon atoms are linked to one or more halogen atoms (fluorine, chlorine, bromine or iodine). Halocarbons containing bromine usually have much higher ozone-depleting potential (ODP) than those containing chlorine. The man-made chemicals that have provided most of the chlorine and bromine for ozone depletion are methyl bromide, methyl chloroform, carbon tetrachloride and families of chemicals known as halons, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).
In 1994, the United Nations General Assembly proclaimed 16 September the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer (resolution 49/114).
As the treaty turns 35 on Ozone Day, we will remember how the Montreal Protocol ended one of the biggest threats ever to face humanity as a whole: the depletion of the ozone layer. When the world found out that ozone-depleting gases used in aerosols and cooling were creating a hole in the sky, they came together. They showed that multilateralism and effective global cooperation worked and they phased out these gases. Now the ozone layer is healing, allowing it once again to shield humanity from the sun’s ultraviolet radiation.
This action has protected millions of people from skin cancer and cataracts over the years since. It allowed vital ecosystems to survive and thrive. It safeguarded life on Earth. And it slowed climate change: if ozone-depleting chemicals had not been banned, we would be looking at a global temperature rise of an additional 2.5°C by the end of this century. This would have been a catastrophe.
In the year of Stockholm+50, marking five decades since the landmark conference that kick-started today’s environmental global movement, the Montreal Protocol has much more to give. Under the Kigali Amendment, nations have committed to phase down hydrofluorocarbons – a move that could avoid up to 0.4°C of global temperature rise by the end of the century. The Protocol and its Amendment are helping the world adopt climate friendly and energy-efficient cooling technology.
What does this mean for humanity? As we continue to protect the ozone layer, it will continue to safeguard us and all life on Earth. It also means a cooler planet as more countries ratify the Amendment. It means more people being able to access vital cooling technology without further warming the planet. It also means the Protocol continuing to send a clear and lasting message: global cooperation to protect life on Earth is our best chance at a brighter future for everyone.
In 1985, the world’s governments adopted the Vienna Convention for the Protection of the Ozone Layer. Under the Convention's Montreal Protocol, governments, scientists and industry worked together to cut out 99 per cent of all ozone-depleting substances. Thanks to the Montreal Protocol, the ozone layer is healing and expected to return to pre-1980 values by mid-century. In support of the Protocol, the Kigali Amendment, which came into force in 2019, will work towards reducing hydrofluorocarbon (HFCs), greenhouse gases with powerful climate warming potential and damaging to the environment.
Many ozone-depleting substances warm the climate, so the agreement has already slowed climate change. The Kigali Amendment to the Montreal Protocol is set to deliver even stronger climate benefits. Under the Amendment, nations have committed to phase down hydrofluorocarbons (HFCs). While HFCs don’t damage the ozone layer, these coolants are powerful greenhouse gases. Reducing their use, as agreed, is expected to avoid up to 0.4°C of global temperature rise by the end of the century, while continuing to protect the ozone layer.
The Kigali Amendment also provides an opportunity for improved energy efficiency in the cooling sector. New innovation replacing HFCs offers an opportunity to redesign air conditioning and refrigeration to use less power, allowing expansion of comfort cooling and cold chain efficiencies without increasing climate impacts. The combination of reducing HFC consumption and improved cold chain efficiencies, particularly in developing economies, will also combat food loss.
Around one third of all food produced globally for human consumption is either lost or wasted each year, largely due to a lack of access to cold chains. Food loss and waste amounts to billions of US dollars a year; not only wasting precious resources such as land, water and energy, but also generating an estimated 8 per cent of total greenhouse gases per year globally.
By developing cold chain solutions that are more efficient, more climate friendly, and cheaper to buy and operate, cold chains will become more effective and widely available. This will provide producers such as farmers and pharmaceutical providers with access to pre-cooling, refrigerated storage and refrigerated transport – ensuring products such as food and vaccines reach people in safe and good condition.
The principal aim of the Montreal Protocol is to protect the ozone layer by taking measures to control total global production and consumption of substances that deplete it, with the ultimate objective of their elimination on the basis of developments in scientific knowledge and technological information.
The Montreal Protocol is structured around several groups of ozone-depleting substances. The groups of chemicals are classified according to the chemical family and are listed in annexes to the Montreal Protocol text.
The Montreal Protocol requires the control of nearly 100 chemicals, in several categories. For each group or annex of chemicals, the Treaty sets out a timetable for the phase-out of production and consumption of those substances, with the aim of eventually eliminating them completely.
The timetable set by the Montreal Protocol applies to consumption of ozone depleting substances. Consumption is defined as the quantities produced plus imported, less those quantities exported in any given year. There is also a deduction for verified destruction.
Percentage reductions relate to the designated base-line year for the substance. The Protocol does not forbid the use of existing or recycled controlled substances beyond the phase-out dates.
There are a few exceptions for essential uses where no acceptable substitutes have been found, for example, in metered dose inhalers (MDI) commonly used to treat asthma and other respiratory problems or halon fire-suppression systems used in submarines and aircraft.
On 16th September 2009, the Vienna Convention and the Montreal Protocol became the first treaties in the history of the United Nations to achieve universal ratification.
The Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer reached agreement at their 28th Meeting of the Parties on 15 October 2016 in Kigali, Rwanda to phase-down hydrofluorocarbons (HFCs).
What is ozone?
Ozone is a special form of oxygen with the chemical formula O3. The oxygen we breathe and that is so vital to life on earth is O2.
Ozone constitutes a very small part of our atmosphere, but its presence is nevertheless vital to human well-being. Most ozone resides high up in the atmosphere, between 10 and 40km above Earth's surface. This region is called the stratosphere and it contains about 90% of all the ozone in the atmosphere.
Why do we care about atmospheric ozone?
Ozone in the stratosphere absorbs some of the Sun’s biologically harmful ultraviolet radiation. Because of this beneficial role, stratospheric ozone is considered “good” ozone. In contrast, excess ozone at Earth’s surface that is formed from pollutants is considered “bad” ozone because it can be harmful to humans, plants, and animals. The ozone that occurs naturally near the surface and in the lower atmosphere is also beneficial because ozone helps remove pollutants from the atmosphere.
The Ozone hole and science
Following the publication of the findings of a British Antarctic Survey article in May 1985, the phenomenon of ozone depletion over Antarctica was referred to as the "ozone hole", a phrase first attributed to Nobel Prize winner Sherwood Rowland. The satellite image of the Ozone Hole has become a global symbol of this environmental threat that has helped mobilize public support for the Montreal Protocol.
The work of atmospheric scientists and environmental researchers continues to play a paramount role in informing the policymaking under the Montreal Protocol. Images and scientific bulletins about ozone depletion are useful communication tools to the public about progress made and challenges ahead.
Source : UN
Last Modified : 9/15/2022