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Fiveable
AP Environmental Science
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Table of Contents
Unit 9 Overview: Global Change
Major Environmental Disasters
Unit 9 Overview: Global Change
9.1 Stratospheric Ozone Depletion
9.2 Reducing Ozone Depletion
9.3 The Greenhouse Effect
9.4 Increases in the Greenhouse Gases
9.5 Global Climate Change
9.6 Ocean Warming
9.7 Ocean Acidification
9.8 Invasive Species
9.9 Endangered Species
9.10 Human Impacts on Biodiversity

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9.2 Reducing Ozone Depletion

Verified for the 2025 AP Environmental Science exam•Citation:

Time for Change

In 1987 the Montreal Protocol was created in an attempt to phase out the production of chemicals responsible for the depletion of the ozone.  This international treaty encouraged the use of chemicals like hydrofluorocarbons (HFCs) that are much more reactive and will break apart before reaching the ozone layer. 

Image courtesy of Pixabay

Due to the continuous creation of ozone in the stratosphere, the damage that was done will reverse over time. The Montreal protocol is one of the most successful international environmental treaties and was able to largely stop the depletion of stratospheric ozone.  

Although hydrofluorocarbons (HFCs) were instrumental in stopping the depletion of the ozone layer, they have very high thermal retention properties and are very strong greenhouse gasses. 

Laws and Acts

Ozone depletion is a significant environmental issue that occurs when chemicals such as chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS) are released into the atmosphere and break down the ozone layer. The ozone layer is a region of the Earth's atmosphere that protects life on the planet from the harmful effects of ultraviolet (UV) radiation.

There are several acts and protocols that have been implemented to address ozone depletion:

  1. Montreal Protocol: This is an international treaty that aims to protect the ozone layer by phasing out the production and consumption of ODS. The protocol has been successful in reducing ODS emissions, and the ozone layer is expected to recover by the mid-21st century as a result.
  2. Clean Air Act: This is a federal law in the United States that regulates the production and use of ODS. The act requires the phaseout of certain ODS and sets limits on the use of others.
  3. European Union Regulation on Ozone-Depleting Substances: This regulation sets limits on the production and use of ODS in the EU and its member states.

Mitigation

There are several ways that individuals and communities can help mitigate ozone depletion:

  1. Reduce the use of products that contain ODS: Many consumer products, such as refrigerators, air conditioners, and aerosol sprays, contain ODS. By choosing products that do not contain these chemicals, we can help reduce ODS emissions.
  2. Support the phaseout of ODS: By supporting the phaseout of ODS through advocacy and consumer choices, we can help ensure that these chemicals are no longer used in products and processes.
  3. Use energy efficiently: Reducing energy consumption can help reduce the use of fossil fuels, which are a significant source of ODS emissions.
  4. Plant trees and other vegetation: Trees and other vegetation absorb CO2 from the air and can help offset some of the impacts of ozone depletion. 🎥 Watch: AP Environmental Science Streams 

Key Terms to Review (8)

Chlorofluorocarbons (CFCs): Chlorofluorocarbons (CFCs) are synthetic compounds made up of carbon, chlorine, and fluorine atoms. They were commonly used in aerosol propellants, refrigerants, and foam-blowing agents but have been phased out due to their harmful effects on the ozone layer.
Clean Air Act: The Clean Air Act is a federal law in the United States that aims to control air pollution and improve air quality. It sets standards for emissions from industries, vehicles, and other sources, and establishes programs to reduce pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter.
European Union Regulation on Ozone-Depleting Substances: The European Union Regulation on Ozone-Depleting Substances is a policy implemented by the European Union (EU) to phase out substances that contribute to ozone depletion. It restricts or bans the production, importation, exportation, sale, use, and recovery of ozone-depleting substances within EU member states.
Hydrofluorocarbons (HFCs): HFCs are synthetic greenhouse gases commonly used as replacements for CFCs and HCFCs in various applications like air conditioning and refrigeration. They do not deplete the ozone layer but have a high global warming potential.
Montreal Protocol: The Montreal Protocol is an international environmental agreement that aims to protect the ozone layer by phasing out the production and use of substances that deplete it, such as chlorofluorocarbons (CFCs).
Ozone-depleting substances (ODS): ODS refers to chemicals or compounds that contain chlorine or bromine atoms which can deplete the ozone layer in the Earth's stratosphere.
Ozone Depletion: Ozone depletion refers to the thinning of the ozone layer in Earth's stratosphere due to the release of certain chemicals like CFCs and halons. This thinning allows more harmful ultraviolet (UV) radiation from the sun to reach the Earth's surface.
Ultraviolet (UV) radiation: UV radiation is a type of electromagnetic radiation emitted by the sun. It has shorter wavelengths than visible light and can cause harmful effects on living organisms, including skin damage and increased risk of cancer.
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Practice QuizGlossary
9.3 The Greenhouse Effect