Reducing Ozone Depletion (College Board AP® Environmental Science) : Study Guide

How can we reduce ozone depletion?

• Ozone depletion can be mitigated by replacing ozone-depleting chemicals with substitutes that do not deplete the ozone layer

• However, some replacements are strong greenhouse gases

International efforts to reduce ozone depletion

Role of UNEP

• The United Nations Environment Programme (UNEP) plays a critical role in the protection of the stratospheric ozone layer through:

  • Raising public awareness

  • Continued research into causes and impacts on health and the environment

  • Supporting governments and industries

  • Creating international agreements

Montreal Protocol on Substances that Deplete the Ozone Layer

• The Montreal Protocol on Substances that Deplete the Ozone Layer, initiated in 1987 under the guidance of UNEP, is a landmark international agreement:

  • This has been revised and strengthened over time to reflect scientific and technological advances (the 1992 Copenhagen summit tightened restrictions further)

  • 24 countries initially signed the protocol, with the total now standing at 197 countries

  • Emissions of ODSs have rapidly fallen from about 1.5 million tonnes in 1987 to roughly 400,000 tonnes in 2010

  • UNEP hopes to end production of all HCFCs by 2040

• The illegal market for ozone-depleting substances is a significant challenge to ozone protection efforts

• To curb the illegal trade of ozone-depleting substances and ensure compliance with international regulations, UNEP recommends

  • Persistent monitoring and enforcement

  • Collaboration with national authorities, customs agencies and relevant stakeholders

Phased reduction

• Gradual reduction schedules for ODSs have allowed industries to adapt

• The Montreal Protocol provides time for the development and adoption of alternatives to ODSs

• The Multilateral Fund (MLF) was established in 1991 to help developing countries meet and maintain Montreal Protocol commitments

  • The MLF provides support for industrial conversion, technical assistance, training, and capacity building for the future

National governments

• National governments play a crucial role in implementing the agreements made under the direction of UNEP and help to promote the transition to ozone-friendly alternatives

  • Governments have passed national regulations to reduce the usage and production of halogenated organic gas, such as chlorofluorocarbons (CFCs)

    • For example, as part of the US commitment to the Montreal Protocol, congress added Title VI to the Clean Air Act, making the EPA responsible for safeguarding the ozone layer

Hydrofluorocarbons (HFCs)

• What are HFCs?

  • Hydrofluorocarbons (HFCs) are chemical compounds containing hydrogen, fluorine, and carbon

  • They were introduced as replacements for CFCs because they do not deplete ozone significantly

• Impact of HFCs:

  • Although less harmful to the ozone, HFCs are potent greenhouse gases (GHGs)

  • They have a high global warming potential (GWP)

  • HFC emissions contribute to climate change by trapping heat in the atmosphere

• Their production and use are regulated under the Montreal Protocol, with efforts underway to phase them out completely

Fluorinated gases (F-gases)

• F-gases, including hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), are commonly used as alternatives in refrigeration, air conditioning and insulation

• While they do not deplete the ozone layer, many F-gases are potent greenhouse gases with high global warming potentials

• Efforts are underway to regulate and reduce the use of F-gases through international agreements like the Kigali Amendment to the Montreal Protocol

Local action

• To reduce ozone depletion, individuals can

• Avoid ozone-depleting substances and products that contain chlorofluorocarbons (CFCs), halonated hydrocarbons, methyl bromide, or nitrous oxide 

  • Use 'ozone friendly' or 'toxic free' products 

  • Avoid using cleaning products that are harmful to the environment 

• Use less transportation 

  • Walk, bike, or carpool when possible

  • Use public transportation

  • Reduce the use of cars

  • Choose electric vehicles and lawn equipment

• Use energy more efficiently

  • Use electricity from clean energy sources

  • Service and maintain electrical goods

  • Look for products with ENERGY STAR® labels (such as refrigerators, freezers, and other appliances)

    • These have lower greenhouse gas emissions and meet strict energy efficiency guidelines

• Maintain and service refrigeration equipment and air-conditioners

  • Air-conditioning equipment regulate indoor temperature and humidity to improve comfort

  • They are widely used in homes, workplaces, vehicles, and public buildings

  • Environmental impacts:

    • Air conditioning is energy-intensive, increasing electricity consumption

    • Traditional air conditioning units used ozone-depleting substances (ODSs) like CFCs

  • Regular maintenance helps identify and repair refrigerant leaks, extend their lifespan, improve efficiency and reduce costs

• Other ways to help

  • Buy local products

  • Dispose of old devices properly

  • Recycle

  • Support legislation to reduce ozone-depleting chemicals