The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 16 September 1987, and entered into force on 1 January 1989. Since then, it has undergone several amendments and adjustments, with revisions agreed to in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing), 2007 (Montreal), 2016 (Kigali) and 2018 (Quito). As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2040 and 2066. Due to its widespread adoption and implementation, it has been hailed as an example of successful international co-operation. Former UN Secretary-General Kofi Annan stated that "perhaps the single most successful international agreement to date has been the Montreal Protocol". In comparison, effective burden-sharing and solution proposals mitigating regional conflicts of interest have been among the success factors for the ozone depletion challenge, where global regulation based on the Kyoto Protocol has failed to do so. In this case of the ozone depletion challenge, there was global regulation already being installed before a scientific consensus was established. Also, overall public opinion was convinced of possible imminent risks.
The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9 to 22 mi) above Earth, although its thickness varies seasonally and geographically.
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.
Freon is a registered trademark of the Chemours Company and generic descriptor for a number of halocarbon products. They are stable, nonflammable, low toxicity gases or liquids which have generally been used as refrigerants and as aerosol propellants. These include chlorofluorocarbons and hydrofluorocarbons, both of which cause ozone depletion and contribute to global warming. 'Freon' is the brand name for the refrigerants R-12, R-13B1, R-22, R-410A, R-502, and R-503 manufactured by The Chemours Company, and so is not used to label all refrigerants of this type. They emit a strong smell similar to acetone. Freon has been found to cause damage to human health when inhaled in large amounts. Studies have been conducted in the pursuit to find beneficial reuses for gases under the Freon umbrella as an alternative to disposal of the gas.
A refrigerant is a working fluid used in cooling, heating or reverse cooling and heating of air conditioning systems and heat pumps where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated because of their toxicity and flammability and the contribution of CFC and HCFC refrigerants to ozone depletion and that of HFC refrigerants to climate change.
Hydrofluorocarbons (HFCs) are synthetic organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFC refrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs), which were phased out from use by the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs) which are presently being phased out. HFCs replaced older chlorofluorocarbons such as R-12 and hydrochlorofluorocarbons such as R-21. HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection.
Dichlorodifluoromethane (R-12) is a colorless gas popularly known by the genericized brand name Freon. It is a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant. In compliance with the Montreal Protocol, its manufacture was banned in developed countries in 1996, and in developing countries in 2010 out of concerns about its damaging effect on the ozone layer. Its only allowed usage is as a fire retardant in submarines and aircraft. It is soluble in many organic solvents. R-12 cylinders are colored white.
1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Klea 134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, HFA-134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane) but with insignificant ozone depletion potential and a lower 100-year global warming potential (1,430, compared to R-12's GWP of 10,900). It has the formula CF3CH2F and a boiling point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored light blue. A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.
R-410A is a refrigerant used in air conditioning and heat pump applications. It is a zeotropic but near-azeotropic mixture of difluoromethane (CH2F2, called R-32) and pentafluoroethane (CHF2CF3, called R-125). R-410A is sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A.
An air source heat pump (ASHP) is a heat pump that can absorb heat from air outside a building and release it inside; it uses the same vapor-compression refrigeration process and much the same equipment as an air conditioner, but in the opposite direction. ASHPs are the most common type of heat pump and, usually being smaller, tend to be used to heat individual houses or flats rather than blocks, districts or industrial processes.
Natural refrigerants are considered substances that serve as refrigerants in refrigeration systems. They are alternatives to synthetic refrigerants such as chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), and hydrofluorocarbon (HFC) based refrigerants. Unlike other refrigerants, natural refrigerants can be found in nature and are commercially available thanks to physical industrial processes like fractional distillation, chemical reactions such as Haber process and spin-off gases. The most prominent of these include various natural hydrocarbons, carbon dioxide, ammonia, and water. Natural refrigerants are preferred actually in new equipment to their synthetic counterparts for their presumption of higher degrees of sustainability. With the current technologies available, almost 75 percent of the refrigeration and air conditioning sector has the potential to be converted to natural refrigerants.
International Day for the Preservation of the Ozone Layer is celebrated on September 16 designed by the United Nations General Assembly. This designation had been made on December 19, 2000, in commemoration of the date, in 1987, on which nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer. In 1994, the UN 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. The closure of the hole in the ozone layer was observed 30 years after the protocol was signed. Due to the nature of the gases responsible for ozone depletion their chemical effects are expected to continue for between 50 and 100 years.
1,1-Dichloro-1-fluoroethane is a haloalkane with the formula C
2H
3Cl
2F. It is one of the three isomers of dichlorofluoroethane. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment.
1-Chloro-1,1-difluoroethane (HCFC-142b) is a haloalkane with the chemical formula CH3CClF2. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment. It is primarily used as a refrigerant where it is also known as R-142b and by trade names including Freon-142b.
Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compounds are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), which are saturated, HFOs are olefins, otherwise known as alkenes.
Fluorinated gases (F-gases) are a group of gases containing fluorine. They are divided into several types, the main of those are hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6). They are used in refrigeration, air conditioning, heat pumps, fire suppression, electronics, aerospace, magnesium industry, foam and high voltage switchgear. As they are greenhouse gases with a strong global warming potential, their use is regulated.
Stephen Oliver Andersen is the Director of Research at the Institute for Governance & Sustainable Development (IGSD) and former co-chair (1989–2012) of the Montreal Protocol Technology and Economic Assessment Panel (TEAP) where he also chaired and co-chaired Technical Options Committees, Task Forces and Special Reports. He is one of the founders and leading figures in the success of the Montreal Protocol on Substances that Deplete the Ozone Layer that has phased out the chemicals that deplete the stratospheric ozone that protects the Earth against the harmful effects of ultraviolet radiation that causes skin cancer, cataracts, and suppression of the human immune system, destroys agricultural crops and natural ecosystems and deteriorates the built environment. Because ozone-depleting chemicals are also powerful greenhouse gases the Montreal Protocol also protected climate. Dr. Andersen was instrumental in the 2016 Kigali Amendment that will phase down hydrofluorocarbons once necessary to phase out chlorofluorocarbons (CFCs) fast enough to avoid ozone tipping points, but no longer necessary now that environmentally superior replacements are available or soon to be available. For his ambitious campaign saving the ozone layer, Dr. Andersen earned the 2021 Future of Life Award along with Joe Farman and Susan Solomon.
K. Madhava Sarma (1938-2010) was the first Executive Secretary of the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol on Substances that Deplete the Ozone Layer from 1991 to 2000 at the United Nations Environment Programme (UNEP). He is considered one of the founders and leading figures in the success of the Montreal Protocol that established legally binding controls on the production and consumption of chemicals that cause ozone depletion and damage the stratospheric ozone layer which protects the Earth against the harmful effects of ultraviolet radiation. These effects include skin cancer, sunburn, permanent blindness and cataracts as well as harm to plants and animals. The Montreal Protocol was recognized by Kofi Annan, former Secretary General of the United Nations as being “perhaps the single most successful international environmental agreement to date" and went on to become the first treaty in the history of the United Nations to be universally ratified in 2008 by 197 countries.
Akkihebbal Ramaiah (Ravi) Ravishankara ForMemRS FAAAS FRSC is a scientist specializing in Chemistry and Atmospheric Sciences, and University Distinguished Professor in the Departments of Chemistry and Atmospheric Sciences at Colorado State University, Fort Collins.
Life Cycle Climate Performance (LCCP) is an evolving method to evaluate the carbon footprint and global warming impact of heating, ventilation, air conditioning (AC), refrigeration systems, and potentially other applications such as thermal insulating foam. It is calculated as the sum of direct, indirect, and embodied greenhouse gas (GHG) emissions generated over the lifetime of the system “from cradle to grave,” i.e. from manufacture to disposal. Direct emissions include all climate forcing effects from the release of refrigerants into the atmosphere, including annual leakage and losses during service and disposal of the unit. Indirect emissions include the climate forcing effects of GHG emissions from the electricity powering the equipment. The embodied emissions include the climate forcing effects of the manufacturing processes, transport, and installation for the refrigerant, materials, and equipment, and for recycle or other disposal of the product at end of its useful life.
