The Montreal Protocol on Substances that Deplete the Ozone Layer, also known simply as the Montreal Protocol, is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.
Open for signature on 16 September 1987, it was made pursuant to the 1985 Vienna Convention for the Protection of the Ozone Layer, which established the framework for international cooperation in addressing ozone depletion.
The Montreal Protocol entered into force on 1 January 1989, and has since undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali).
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 2050 and 2070.
The Montreal Protocol's success is attributed to its effective burden sharing and solution proposals, which helped mitigate regional conflicts of interest, compared to the shortcomings of the global regulatory approach of the Kyoto Protocol. However, global regulation was already being installed before a scientific consensus was established, and overall public opinion was convinced of possible imminent risks with the ozone layer.
The Vienna Convention and the Montreal Protocol have each been ratified by 196 nations and the European Union, making them the first universally ratified treaties in United Nations history.
More information: UN Environment Programme
Due to its widespread adoption and implementation, the Montreal Protocol has been hailed as an example of exceptional international cooperation, with Kofi Annan describing it as perhaps the single most successful international agreement to date.
The treaties are also notable in the unique expedience of global action, with only 14 years lapsing between a basic scientific research discovery (1973) and the international agreement signed (1985 and 1987).
The treaty is structured around several groups of halogenated hydrocarbons that deplete stratospheric ozone.
All of the ozone depleting substances controlled by the Montreal Protocol contain either chlorine or bromine, substances containing only fluorine do not harm the ozone layer.
In 1973, the chemists Frank Sherwood Rowland and Mario Molina, who were then at the University of California, Irvine, began studying the impacts of CFCs in the Earth's atmosphere.
They discovered that CFC molecules were stable enough to remain in the atmosphere until they got up into the middle of the stratosphere where they would finally, after an average of 50–100 years for two common CFCs, be broken down by ultraviolet radiation and release a chlorine atom.
Rowland and Molina then proposed that these chlorine atoms might be expected to cause the breakdown of large amounts of ozone (O3) in the stratosphere. Their argument was based upon an analogy to contemporary work by Paul J. Crutzen and Harold Johnston, which had shown that nitric oxide (NO) could catalyze the destruction of ozone.
Several other scientists, including Ralph Cicerone, Richard Stolarski, Michael McElroy, and Steven Wofsy had independently proposed that chlorine could catalyze ozone loss, but none had realized that CFCs were a potentially large source of chlorine.
Crutzen, Molina and Rowland were awarded the 1995 Nobel Prize for Chemistry for their work on this problem.
The environmental consequence of this discovery was that, since stratospheric ozone absorbs most of the ultraviolet-B (UV-B) radiation reaching the surface of the planet, depletion of the ozone layer by CFCs would lead to an increase in UV-B radiation at the surface, resulting in an increase in skin cancer and other impacts such as damage to crops and to marine phytoplankton.
Then, in 1985, British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jon Shanklin published results of abnormally low ozone concentrations above Halley Bay near the South Pole. They speculated that this was connected to increased levels of CFCs in the atmosphere.
It took several other attempts to establish the Antarctic losses as real and significant, especially after NASA had retrieved matching data from its satellite recordings. The impact of these studies, the metaphor ozone hole, and the colourful visual representation in a time lapse animation proved shocking enough for negotiators in Montreal, Canada, to take the issue seriously.
More information: UN Environment Programme
Also in 1985, 20 nations, including most of the major CFC producers, signed the Vienna Convention, which established a framework for negotiating international regulations on ozone-depleting substances. After the discovery of the ozone hole by SAGE 2 it only took 18 months to reach a binding agreement in Montreal.
But the CFC industry did not give up that easily. As late as 1986, the Alliance for Responsible CFC Policy, an association representing the CFC industry founded by DuPont, was still arguing that the science was too uncertain to justify any action.
The main objective of the Multilateral Fund for the Implementation of the Montreal Protocol is to assist developing country parties to the Montreal Protocol whose annual per capita consumption and production of ozone depleting substances (ODS) is less than 0.3 kg to comply with the control measures of the Protocol. Currently, 147 of the 196 Parties to the Montreal Protocol meet these criteria, they are referred to as Article 5 countries.
It embodies the principle agreed at the United Nations Conference on Environment and Development in 1992 that countries have a common but differentiated responsibility to protect and manage the global commons.
Since the Montreal Protocol came into effect, the atmospheric concentrations of the most important chlorofluorocarbons and related chlorinated hydrocarbons have either leveled off or decreased.
Halon concentrations have continued to increase, as the halons presently stored in fire extinguishers are released, but their rate of increase has slowed and their abundances are expected to begin to decline by about 2020.
The Montreal Protocol is also expected to have effects on human health. A 2015 report by the U.S. Environmental Protection Agency estimates that the protection of the ozone layer under the treaty will prevent over 280 million cases of skin cancer, 1.5 million skin cancer deaths, and 45 million cataracts in the United States.
More information: UNO
That being said, we have to be more conscious of the sun
and what it can do to your skin.
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