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Protecting the ozone layer is a success story of international environmental protection

The ozone layer protects the earth from the sun's harmful UV radiation. Emissions of substances that deplete the ozone layer have been successfully reduced globally and the ozone layer is gradually recovering.
Aurinko ja pilviä sinisellä taivaalla.
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Ozone depletion

The ozone layer in the stratosphere protects the earth from the sun's harmful UV radiation, which increases skin cancer and eye diseases and has a harmful effect on land and water ecosystems. In the 1970s, it was discovered that chemicals produced by humans are destroying the ozone layer.

Ozone-depleting substances have been used, e.g. as propellants, refrigerants, in foam blowing, fire extinguishing and as solvents. When a substance that depletes the ozone layer reaches the stratosphere, a chain of reactions starts, where a single chlorine atom can destroy a huge amount of ozone.

Ozone-depleting substances

Ozone-depleting substances (ODS) include e.g.

  • chlorofluorocarbons, i.e. CFCs, used as refrigerants and blowing agents for foams (so-called freons, e.g. refrigerants R-12 and R-502),
  • hydrochlorofluorocarbons, i.e. HCFC compounds, used as refrigerants blowing agents for foams (e.g. refrigerant R-22),
  • halons used as extinguishing agents 
  • methyl bromide used in pest control

There are alternatives for ozone depleting substances in almost all areas of use. In Finland, ozone depleting substances can no longer be used except in certain limited laboratory analyzes and in fire extinguishers in critical applications.

You can find more information on the restrictions on ozone depleting substances on the page F-gases and ozone-depleting substances. In the EU, the use of ODS is regulated by regulation 1005/2009 on substances that deplete the ozone layer (ozone regulation).

The aim is also to mitigate climate change

Ozone-depleting substances are also very strong greenhouse gases, which means that the international environmental agreement to protect the ozone layer (Montreal Protocol) has also mitigated climate change. Ozone-depleting substances have been replaced by fluorinated greenhouse gases (F-gases), especially HFC substances. They do not destroy the ozone layer, but they are powerful greenhouse gases. For most uses, alternatives have been developed that are safe for the ozone layer and do not contribute to global warming. Mitigating climate change became an official goal of the Montreal Protocol when HFCs were included from 2019.

HFC substances included in the Montreal Protocol - Kigali Amendment

Reduction of the use and production of HFC substances was agreed upon in 2016 in Kigali with the amendment to the Montreal Protocol. It entered into force worldwide on January 1, 2019. Different groups of countries have different reduction schedules.

In the EU, HFC substances are covered by Regulation (EU) No. 517/2014 of the European Parliament and the Council on fluorinated greenhouse gases (F-gas regulation). It implements the obligations of the Kigali Amendment in the EU and contains some stricter measures than the Montreal Protocol. More information on the regulation of F-gases can be found on the page F-gases and ozone-depleting substances.

Limiting the global temperature rise requires international action. The Kigali Amendment to the Montreal Protocol is one important step on the way towards the goal of the Paris Climate Agreement to limit the increase in the global average temperature to a maximum of two degrees. 

Phasedown schedules of HFCs in the Kigali Amendment
(group 1)
(group 2**)
baseline (years and
starting point)
2011-2013 average HFC consumption 2020-2022 average HFC consumption 2024-2026 average HFC consumption

share of ODS (HCFC)
that are still in use
and are taken into
account in calculating
the baseline

15% of baseline* 65% of baseline 65% of baseline
freeze year - 2024: 100% of baseline 2028: 100% of baseline
1st step 2019: 90% 2029: 90% 2032: 90%
2nd step 2024: 60% 2035: 70% 2037: 80%
3rd step 2029: 30% 2040: 50% 2042: 70%
4th step 2034: 20%    
final step
2036 and onwards: 15% 2045 and onwards: 20% 2047 and onwards: 15%

*Russia, Belarus, Kazakhstan, Tadzhikistan, Uzbekistan: HCFC share at baseline 25%, first reduction steps 5% reduction 2020 and 35% reduction 2025. **Group 2: Kuwait, United Arab Emirates, Bahrain, Saudi Arabia, Oman, Qatar, India, Iran, Iraq, Pakistan.

The future of the ozone layer

Recovery of the ozone layer is estimated to take several decades, because the substances that destroy it remain in the atmosphere for a long time. The biggest threats to the ozone layer worldwide are global warming and its impacts on the ozone layer, emissions into the atmosphere from existing equipment and banks, and illegal production and use of ozone-depleting substances. 


E-mail address for issues related to ozone-depleting substances and fluorinated greenhouse gases at the Finnish Environment Institute (Syke): 


Finnish Environment Institute (Syke)