What is the Montreal Protocol? Its Importance


The discovery of the ozone layer hole meant bad news for everyone. They found out that the main cause of this phenomenon is various man-made activities. Scientists and world leaders knew that man-made activities would solve the problem. Thus, the Montreal Protocol was born.

They identified various ozone-depleting substances as the catalyst for this problem. It became the main focus of the Montreal Protocol. They believed that addressing the root cause was the best way to fix the problem. For that reason, they decided on implementing a stepwise manner of phasing out these ODSs. The initial purpose was to limit their use simply. Still, studies showed that this is not enough. The ideal way of dealing with the problem is to prohibit these substances completely.

Sign that says Montreal

Fortunately, they were right in their assumption. The gradual phasing out of ODSs yielded positive results. Namely, the levels of the ODSs have been in constant decline since it was enacted. Now, the ozone layer hole is smaller than ever. It also indirectly positively affected other world problems, including poverty and climate change. It has also affected the global food supply and public health.

All these positive impacts make the Montreal Protocol an important global treaty.

It was the talk of the world when it was discovered that there was a hole in the ozone layer decades ago. Common folk took it literally, believing there was an actual hole in that layer. Anyone who ends up under it will get the worst case of sunburn, among others. Scientists would later clarify that this hole is not an actual but a phenomenon resulting in ozone layer depletion.

One of the immediate global reactions to this discovery is to craft various laws to address the issue. These were enacted to stop further damage. But nothing is more all-encompassing than the Montreal Protocol among these different laws.

Before its establishment, most local laws focused on lessening depleting substances to lessen their effects on the ozone layer. The Montreal Protocol took a more active role. Its primary goal was to completely prohibit the use and production of such substances after some time.

Most people are unaware of what the Montreal Protocol is and its importance. It is important to understand its essentials to know how it has evolved. This landmark deal is acknowledged as the most successful environmental law. It is seen as the major catalyst for the ozone layer’s recovery.

What is it, and Why is it Important?

Most people may have likely heard the Montreal Protocol in passing but have no clue what it is and why it is important. They may have a vague idea that it is related to the ozone layer because of the abundance of news about it in the past. Still, they do not fully understand why this is considered a globally significant law.

Scientists initially believed the ozone layer to remain permanently undamaged. It was discovered that this is not the case over the years. Scientists made a startling discovery in 1985. They found out there are parts of it above Antarctica where the levels have dropped below the historically low levels. This discovery was instrumental in crafting the Vienna Convention for the Protection of the Ozone Layer in 1985.

Despite being considered one of the landmark environmental laws, the Vienna Convention mostly focused on research and fact-finding. There were still some skeptics about the reports coming out and even the ozone layer itself. Because of this, the participating countries had a hard time agreeing on what the control measures should be. It was a struggle dealing with more research cooperation. They could not craft laws that would deal to reduce the ozone layer hole.

To fill this important gap, the Montreal Protocol was enacted in September 1987. It was also the result of the scientific community and world leaders reaching a consensus on the ozone layer. It was after much confirmatory research and studies.

Unlike the Vienna Convention, it took a more active role in addressing the matter. It was confirmed that certain substances negatively affect the ozone layer once they reach the stratosphere. Its primary goal is to gradually phase out these substances, which will reduce the continued depletion.

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International laws and protocols are known to be extensive. That is why we have provided a summary of the multilateral Montreal Protocol. Hopefully, it’ll help you understand this environmental treaty better. Why was its success beneficial for all humanity?

World leaders decided to be more active in dealing with the issues as it was discovered that the ozone layer is becoming depleted. It is mainly due to certain substances being released into the atmosphere that reaches it.

The concrete actions to address the problem started with establishing the Vienna Convention. Its goal was to protect humans and the environment from its depletion. This convention did not establish rules to achieve this, and it resulted in the adoption of the Montreal Protocol in 1987.

It aimed to decrease the substances that cause the depletion of the ozone layer. It was done by initially phasing down their production and importation. Limiting the use of chlorofluorocarbons (CFCs) and halons was a big priority. These two were widely used in various household products considered essential. That is why it was decided that they must be phased down first.

The immediate outright banning of these substances would also pose a problem. According to a set timetable, the Montreal Protocol promoted the gradual phasing down of these substances. This would allow people ample time to discover more eco-friendly alternatives. Manufacturers could adjust to various products that rely on these substances to work.

It divides countries into two specific categories, namely developing and developed countries. This categorization resulted in different timetables. Developing countries were generally given more time for the phasing out of these substances than developed countries. It was thought that 10 to 15-year windows were more realistic for them. They acknowledge the challenges these developing countries will face, particularly financially and technologically. Complying with the protocol would prove challenging, hence the longer timetable.

Phasing out these harmful substances is the main goal of the Montreal Protocol. It also acknowledges that there are still some instances when using them is necessary. Because of this, they came up with provisions specifying when they can be used but only in controlled amounts. That is if they meet the strict criteria set. Suppose the purpose of using these substances is considered essential or critical. In that case, it may be allowed if it meets the specific conditions set.

The main goals during the creation were:

  • Start the phasing down of CFCs in 1993 and decrease it by 20% in 1994 compared to the consumption level in 1986. The goal was to reduce it by half by 1998 finally.
  • Freeze or restrict the manufacture and use of three specific halons in developed countries by 1993. It compared their levels to the 1986 levels.
  • Restrict the trading of these substances between signatories and non-participants. It was done to prevent the transfer of facilities involved in their production to non-signatory countries.

The Montreal Protocol eventually changed its main objective from phasing down and limiting its use. It changed to phasing out of these substances in the future. CFCs are the first to be phased out. It’s followed by the other substances later added to the list after various amendments to the Protocol over the years.

The signatories eventually established a Multilateral Fund for those developing countries to meet the goals. This fund aims to aid these particular countries to meet the timelines set. It’s done through the gradual phasing out of these harmful substances. Checking on the progress of all the signatories in meeting the established timeframes is challenging. It requires the submission of progress reports and assessments from every member party.

All these efforts paid off and continue to do so. The ozone layer hole is now at its smallest size since it was first discovered. The amount of depleting substances present has decreased by 98% compared to the levels back in the 1990s.

It has achieved so much relatively short compared to other environmental laws.

Which Problem Does It Address?

You may have guessed by now that the Montreal Protocol addresses the problem of the depletion of the ozone layer. The purpose of the Vienna Convention is also to protect the ozone layer. It failed to establish global concrete actions to do so. The Montreal Protocol was the first of its kind. It took a more active approach with the phasing down of depleting substances under the umbrella of this convention. It later led to an outright banning but was done in steps.

Without this landmark treaty, scientists believe that the ozone layer may be gone by 2050. It would lead to catastrophic consequences for everyone. Scientific evidence has shown that the hole has been growing at an alarming rate since its discovery. The Montreal Protocol managed to slow it down over the years.

UN Secretary-General Antonio Guterres also mentioned that the Montreal Protocol would address other key global problems. It is also believed to help meet the Sustainable Development Goals (SDG) set in global poverty and health. It would help climate change and food supply. They know that it will set a positive chain reaction. It’s done by addressing ozone layer depletion and the other problems indirectly caused or worsened by the hole.

How Does the It Reduce Depletion?

The Montreal Protocol acknowledges that it is man-made activities that are the biggest catalyst of the depletion and that it is vital to reduce this. In particular, certain substances have the biggest effects.

The hole is also caused by a natural phenomenon that occurs during spring. Scientists found out that these ozone-depleting substances (ODS) cause the rapid increase of the hole. Because of this discovery, they realized that reducing the source of the depletion will reduce the depletion itself.

They acknowledged that this was easier said than done because these substances were abundantly used for so long. They did not know that they remained in the atmosphere for a long time. When the ODS reaches the ozone layer, they destroy the essential molecules. With less ozone present, the size of the hole increases.

Scientists have also discovered that depleting substances stay in the atmosphere longer than desired. While most of them can linger for years, some specific ODS remain in the atmosphere even for decades. CFCs were discovered in the 1920s, but it was only around the 1980s that it was confirmed to be harmful to the ozone layer. This means for more than six decades. Ozone was destroyed faster than it was created because of the ODS present.

For decades, CFCs and other depleting substances were widely used in various consumer goods. It included things such as air conditioners and aerosol cans. Manufacturers even reportedly produced as much as 1.2 million tons of depleting substances in 1986 to meet consumer needs. This demand meant that there were no limits on ODS production and the products that used them at that time.

But with, its introduction led to the much-needed control over these substances. By limiting the ODS, its production lessened. Manufacturers had to develop alternatives for products that required ODSs to function. This move led to the much-needed increase in the creation of ozone molecules to reverse the depletion.

Scientists have acknowledged the Montreal Protocol’s critical role in achieving this feat, further proving its effectiveness. Despite being capable of “healing itself,” it cannot do so if the depleting substances have not been limited or completely banned.

What Substances Deplete It And Causes The Hole to Grow?

More than a hundred substances deplete the ozone layer based on scientific research and evidence. These are collectively known as depleting substances. These ODSs are man-made compounds or chemicals that typically contain chlorine and bromine. They can also be combined with fluorine, hydrogen, and carbon.

The ODS that combine the atoms above are known for their stability, allowing the undamaged ozone layer. The rain cannot dissolve or push them back to earth, unlike other compounds. It means they are free to drift upwards anytime.

Ultraviolet radiation breaks the compounds apart when these gases reach the ozone layer. It separates the chlorine and bromine, turning them into free atoms. Once they interact with the molecules, a reaction destroys the ozone molecules.

A chlorine or bromine atom can singlehandedly destroy at least 100,000 molecules before vanishing. Since these are abundantly present in ODS, they cause a massive loss of ozone molecules. It leads to the depletion of the ozone layer.

Any substance that contains either chlorine or bromine can become a catalyst that will cause the depletion.

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Which Chemicals are Controlled by This Agreement?

The identification of the various ODSs happened over the years. The Montreal Protocol established control over the use of such chemicals. To make it easily identifiable, they sorted these chemicals into the following general categories:

  • Chlorofluorocarbons
  • Halons
  • Hydrochlorofluorocarbons
  • Carbon Tetrachloride
  • Methyl Chloroform
  • Methyl Bromide
  • Bromochloromethane
  • Hydrobromofluorocarbons

The full list of chemicals controlled by it can be found here.

CFCs were the first chemicals to be identified as depleting. CFCs proliferated in the atmosphere for decades because of their stability and fire resistance. They are also non-toxic. They also provide effective heat absorption. They were used as coolants for refrigerators and air conditioners, with Freon being its most identifiable form. They were also common in solvents and aerosol propellants. CFCs are a combination of chlorine, carbon, and fluorine atoms and are also considered greenhouse gases.

Best known as an integral component of fire extinguishers, halons were also identified as an ODS early together with CFCs. Halons are made up of fluorine, bromine, and carbon. They are safe for use as long as it is within recommended levels or concentrations. Despite this, its ozone-depleting potential or ODP is the highest because of the bromine present. In particular, Halon 1301has the highest ODP among all known ODSs.

It was developed as an alternative to CFCs. Hydrochlorofluorocarbons or HCFCs consist of chlorine, carbon, fluorine, and hydrogen atoms. Hydrogen makes the HCFCs more stable than CFCs and is broken down in the stratosphere. It causes less damage to the ozone layer. Despite this, HCFCs have also been considered greenhouse gases. It prompted them to be eventually banned.

Carbon tetrachloride was once essential to the production of CFCs. It was used as feedstock or raw material before the Montreal Protocol was enacted. Consisting of carbon and chlorine, it was also used in agricultural pesticides and fumigants. It was common in industrial solvents and paints, and fire extinguishers. Finally, it could be found in pharmaceuticals and dry cleaning agents.

Methyl chloroform was also developed as a substitute, but this time for carbon tetrachloride. Methyl chloroform consists of chlorine, hydrogen, and carbon, known as hazardous to humans. It was often used as an industrial solvent, particularly for degreasers and adhesives. That is why it was widely used in manufacturing equipment and electronics.

Primarily used in the agriculture industry, methyl bromide is another chemical considered an ODS. It is also used as a fumigant for agricultural products and soil fumigation. It can work as a disinfectant for food-processing facilities. The Protocol still allows controlled use composed of hydrogen, carbon, and bromine. There are no effective alternatives for it yet.

Bromochloromethane is also known as Halon 1011 but is not considered halon. It’s because it combines chlorine, carbon, hydrogen, and bromine. It was also formulated as an alternative to carbon tetrachloride for fire extinguishers. However, it is known as a toxic substance.

Also known as HBFCs, hydro Bromo fluorocarbons exhibit the same properties as CFCs and halons due to their chemical composition. HBFCs consists of a frame of hydrogen and carbon, with bromine or fluorine attached to it. But unlike its counterparts, it was not extensively used worldwide.

Some of the ones that emit chlorine include:

  • chlorofluorocarbons
  • methyl chloroform
  • carbon tetrachloride
  • and hydrochlorofluorocarbons

Ones that emit bromine include methyl bromide and halons. So far, there’s a range of them already phased out. In contrast, HCFCs and methyl bromide will follow suit after several decades.


Little girl who looks excited

It now seems that most of the world complies with various measures to prohibit the production and use of ODSs. Not all of them are part of the original countries that enacted the Montreal Protocol. Only 46 countries belonging to the United Nations were the first signatories. Despite this, they achieved a major stride. It prompted the other nations to become signatories later.

The 46 original signatories are:

Original countries
Antigua and BarbudaEgyptItalyNorwayTogo
AustraliaEuropean UnionJapanPanamaUganda
BelarusFranceLuxembourgPortugalUnited Kingdom of Great Britain and Northern Ireland
BelgiumGermanyMaldivesRussian FederationUnited States of America
Burkina FasoGhanaMaltaSenegalBolivarian Republic of Venezuela

Over the years, more countries signed up to become a party to the Montreal Protocol. Those who joined after it was enacted are:

Countries that joined later 
AfghanistanCook IslandsHondurasMontenegroSingaporeVietnam
AlbaniaCosta RicaHungaryMozambiqueSlovakiaYemen
AlgeriaCôte d’IvoireIcelandMyanmarSloveniaZambia
AndorraCroatiaIndiaNamibiaSolomon IslandsZimbabwe
AngolaCubaIslamic Republic of IranNauruSomalia 
Antigua and BarbudaCyprusIraqNepalSouth Africa 
ArmeniaCzech RepublicJamaicaNicaraguaSouth Sudan 
AzerbaijanDemocratic People’s Republic of KoreaJordanNigerSri Lanka 
BahamasThe Democratic Republic of the CongoKazakhstanNigeriaSt. Kitts and Nevis 
BahrainDjiboutiKiribatiNiueSt. Lucia 
BangladeshDominicaKuwaitNorth MacedoniaSt. Vincent and the Grenadines 
BarbadosDominican RepublicKyrgyzstanOmanState of Palestine 
BelizeEcuadorLao People’s Democratic RepublicPakistanSudan 
BeninEl SalvadorLatviaPalauSuriname 
BhutanEquatorial GuineaLebanonPapua New GuineaSweden 
Plurinational State of BoliviaEritreaLesothoParaguaySwitzerland 
Bosnia and HerzegovinaEstoniaLiberiaPeruThe Syrian Arab Republic 
Brunei DarussalamFijiLithuaniaRepublic of KoreaTonga 
BulgariaGabonMadagascarRepublic of MoldovaTrinidad and Tobago 
BurundiThe GambiaMalawiRomaniaTunisia 
Cabo VerdeGeorgiaMalaysiaRwandaTurkey 
CameroonGuatemalaMarshall IslandsSan MarinoTuvalu 
The Central African RepublicGuineaMauritaniaSao Tome and PrincipeUnited Arab Emirates 
ChadGuinea-BissauMauritiusSaudi ArabiaUnited Republic of Tanzania 
ChinaGuyanaFederated States of MicronesiaSerbiaUruguay 
ComorosHoly SeeMongoliaSierra LeoneVanuatu 

All UN member states and the Holy See and Palestine participate in the Montreal Protocol. From the original 46 countries, the member parties are now 198.


Like any other global treaty or law, the Montreal Protocol had various amendments over the years. It kept it updated to meet the pressing needs and concerns over time. As of this time, there are five amendments made to it:

The London Amendment focused on adjusting and strengthening the original measures crafted to control the ODSs. It was particularly CFCs, carbon tetrachloride, and halons. They were set to be phased out by 2000 and 2010 in developed and developing countries, respectively. It also introduced methyl chloroform to the list of controlled ODSs. It promoted continuous research on its legal and scientific issues. It also established the Multilateral Fund for developing countries to meet their goals.

The primary purpose of the Copenhagen Amendment was to adjust the timelines set so that the phasing out of the known ODSs. It was done to make sure it would occur much earlier. It also set the phaseout of HCFCs to 2004 in developed countries and adjusted the phaseout.

Supplementing the Copenhagen Amendment is the Montreal Amendment that pushed for the phaseout of HCFCs in developing countries. Methyl bromide should follow suit in developed countries in 2005 and developing countries by 2015.

The Beijing amendment was later introduced to have stricter control over HCFCs, particularly their manufacture and trade. It also added bromochloromethane to its list of ODSs and set its phaseout goal to 2004.

After discovering that the supposedly less harmful HCFCs are worsening climate change, the Kigali Amendment sought its phasing down. It was later identified as a greenhouse house. Its manufacture and use may not contribute to the depletion of the ozone layer, but it does affect the climate.

Only five amendments have been made so far. It will not be surprising if the parties meet up again in the future to discuss further amendments. It is particularly with the scheduled phasing out of ODSs. These changes were necessary to meet the goals set and make much-needed adjustments, depending on the severity of the depletion.

How Does It Work?

Despite undergoing multiple amendments over the years, the working of the Montreal Protocol remains essentially the same. It promotes the phasing out of ODSs in both developed and developing countries. It’s done according to the set timelines and in a stepwise manner.

These timelines vary according to the ODSs and the country involved, but they follow a general pattern:

  • The first step involves halting the production of these ODSs. By freezing its manufacture, member parties expect the ODSs levels to be lower than the reference levels set. These reference levels can either be the average level in a specific year or period, depending on the ODSs.
  • Minus percentages relative to these reference levels should be reached by the dates set. The number of these targets will also depend on the specific ODSs. Some may have only one target minus percentage by a certain year. In contrast, others may have multiple targets over the years.
  • Following the pattern of decline in ODSs levels, the phaseout dates will be set.

Here is the set timeline for HCFCs for developed countries, with the average level of 100% CFCs and 2.8% of HCFCs in 1989 used as the reference level:

  1. Freeze its production by early 1996.
  2. Reduce it by 35% by 2004.
  3. Reduce it by 75% by 2010.
  4. Reduce it by 90% by 2015.
  5. Complete phaseout by 2020.

By setting a timeline, all member parties are expected to meet these respective deadlines to meet their goals. The Protocol mandates that they provide accurate progress reports annually to track individual countries’ progress. This monitors each country’s compliance and progress in terms of the schedules set. It also monitors the overall effectiveness of the Protocol in prohibiting these ODSs.

Member parties acknowledge that developing countries will likely experience difficulties meeting the goals compared to developed countries. That is why they decided to establish the Multilateral Fund for the Implementation of the Montreal Protocol. This fund provides financial assistance to help these developing countries meet the schedules set. It is replenished every three years.

These member parties also have annual meetings to check on the overall progress in meeting its objectives. It’s also to keep themselves updated with the latest scientific findings. They aim to develop ways to make all participants more compliant and meet their respective timelines.

The overall process is straightforward, but meeting the goals of the Montreal Protocol involves a lot of work. If a member party fails to meet its target or non-compliance, they have come up with measures that can be done. Depending on the case, these can be done by providing the needed assistance. They can also reprimand or caution, or even suspend. The purpose of these measures is to ensure compliance of member parties.

Why Was It Successful?

The Montreal Protocol is considered the most successful among all environmental laws created. This claim can be justified by various scientific evidence, but there is no evidence more decisive than shrinking the hole.

If you recall, this hole resulted from the ODSs present over the years. These ODSs are the main focus since they see them as the main source of the depletion. By prohibiting the production and consumption of the ODSs, they believe that the ozone layer will eventually recover. It is what is happening now.

The continued success is due to multiple factors, such as:

  • Cooperation between all member parties. They had a very specific goal backed by ongoing scientific research. It was easier for them to develop real solutions and ways to enforce them. They also encouraged the participation of key informants, which are the scientists. This greatly helped them in decision-making.
  • Financial aid encouraged everyone to participate. There is a generally low expectation for low-income countries to participate in global treaties and laws fully. It’s due to financial constraints. The Montreal Protocol begs to differ. Providing funds to these countries will enable them to meet their goals.
  • Awareness of the worst-case scenarios. There was widespread alarm with the discovery of the ozone layer, leading to many misconceptions. These misconceptions also helped because they pushed people to take immediate actions to fix the problem. They were finding out the actual effects of the depletion also helped. They realized that humans are not the only ones affected and that the situation would be that bad.
  • More freedom and less formality. Member parties were encouraged to participate, and they also promoted flexibility. They may have established the Protocol, but there is leeway to make further changes to tailor-fit it to achieve their goals. It resulted in various amendments over the years.
  • Early identification of ODSs. They know which substances are destroying the ozone layer early on and as further research comes in. They can address them immediately and identify which ones need to be prioritized and phased out first.
  • Participation in various industries. Those known producers of ODSs and products that use them were more than happy to comply with the protocol. The ODSs they make or use were starting to become obsolete. Finding more efficient alternatives meant they could save money in the long run.
  • Ordinary people also complied. People have a general understanding that the hole is bad news. They were more active in preventing the worst-case scenarios they imagined from happening. Even basic information and misconceptions were enough to motivate them to participate in programs that address ozone layer depletion.

All these factors were essential in ensuring the continued success of this document. People saw the positive results of their actions, as well as experiencing the negative effects of ozone layer depletion. It made them even more motivated to reverse the problem.

Is It Still in Effect?

We are getting consistently good news about the ozone layer lately and that it can heal itself over time. You may wonder if the Montreal Protocol is still in effect. After all, all these make it seem that there is already no need for the Protocol. The short answer is: yes. They recently added money to the Multilateral Fund for the developing countries.

While there have been major strides over the years, there is still much to be done. It’s especially in developing countries. Some violators still produce ODSs and products that require these ODSs. It’s despite already prohibiting their production and use. These ODSs are also still present in the atmosphere, although they are now at generally lower levels.

The ozone layer may quickly recover, but it can also become damaged. It’s especially since most ODSs remain in the atmosphere for years. Many ODSs are already banned. Some are still in the process of being phased out, which means they are still being used, even in smaller amounts.

With the Montreal Protocol in place, it ensures that known ODSs will continue to decrease over time. It’s until it reaches the date when it becomes completely banned. There is always a possibility that new ODSs may be discovered, just like what happened several times in the past. That is why constant monitoring is still needed. Early discovery makes early phasing out of these new ODSs possible.

Certain ODSs have already been banned, but some ODSs whose phaseout dates are still decades from now. Because of this, the member parties still need to monitor each other’s progress following the Protocol. They may also need to make subsequent amendments and adjustments in the future, just like what happened in the past.

Until all these ODSs have been prohibited and the ozone layer hole has been completely repaired, you can expect the Montreal Protocol to remain. It may mean more hard work for many, but the benefits for all mankind and the environment makes everyone’s efforts worth it.

We are already reaping the benefits of the decades-long effort. There is no reason to stop now, especially because the ozone layer hole is still there. Even if it is now smaller, we have to continue.

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Did the Montreal protocol ban CFCs?

It wasn’t completely banned. CFCs and other numerous substances were to be phased out in the agreements in the Montreal Protocol of 1987. It became the starting point of the whole band of Chloro-Fluoro-carbons on earth.

Was the Montreal protocol successful?

Many factors display that the Montreal Protocol was largely successful. This includes the depletion of the stratospheric chlorine. Other halogen-sources gases have also seen a decline. Some gases like halons and HCFCs are still increasing, but we could witness a decline if compliance continues.

What damages the ozone layer?

Specifically, it is bromine and chlorine atoms that damage the ozone layer. Other substances include CFCs and HCFCs. Halons, Carbon tetrachloride, and methyl bromide.

What are the things CFCs were primarily used in?

CFCs are primarily used in the manufacturing of aerosol agents, like deodorants. It is also used in refrigerants put in refrigerators and automobiles. Nowadays, they are not used in refrigerators any longer. They are also used in blowing agents and foams.

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