The ozone layer is a region of the Earth’s stratosphere that contains a relatively high concentration of the gas ozone (O3). This concentration allows the ozone layer to absorb most of the sun’s ultraviolet light, protecting Earth’s inhabitants from the harmful energy. In the 1970s, the threat to the ozone layer was one of the first environmental hazards that captured the attention of the general public. Scientists warned that action needed to be taken to repair the hole in the protective ozone layer to prevent millions of cases of skin cancer around the globe. Politicians, corporate leaders and scientists worked together to envision and ratify the Montreal Protocol. This collaborative effort has shown promise. This year, scientists announced that the ozone layer hole was beginning to heal. In this lesson, students will explore the scientific, political, economic and social events that led to the depletion of the ozone layer, as well as the global response.
Healing the Ozone: First Steps Toward Success
A worldwide effort to heal damage to the ozone layer is showing early progress.
Earth’s ozone layer acts as a protective shield, absorbing and blocking harmful radiation from the Sun. In the 1970s, scientists began to worry that the ozone layer was being depleted by manufactured chemicals like chlorofluorocarbons, or CFCs, commonly used as a refrigerant and in aerosols.
Soon pressure grew for global action. In 1987, a United Nations summit in Montreal brought global leaders, scientists, and industry representatives together to address the problem.The treaty they ratified, known as the Montreal Protocol, was ultimately a success, pushing chemical companies to invest in profitable alternatives to help save the ozone. Earlier this year, scientists announced that Earth’s ozone layer was starting to recover.
The Montreal Protocol has been recognized as a template for encouraging science-based policy and global cooperation to address environmental challenges. Today, as global warming caused by burning fossil fuels has become the most pressing climate problem, will the world be able to duplicate the Montreal Protocol’s success?
This documentary was created in partnership with Scientific American. You can view past collaborations here.
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- Lesson plan 1: First Steps Toward Healing the Ozone
- Lesson plan 2: Cabinet Simulation for Environmental Policy
- Lesson plan 3: Exploring Environmental Issues and Solutions
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- Producer: Jonathan Schienberg
- Editor: Heru Muharrar
- Associate Producer: Emily Orr