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.

Subscribe to our newsletter for our latest work and surprises from history.

Educators, click below for a lesson plan for this video, and check out the Environmental Education Collection. Sign up for our educator newsletter to receive classroom resources, and browse more lesson plans and videos here.

For teachers
  • Read transcript
  • Book a producer
  • Producer: Jonathan Schienberg
  • Editor: Heru Muharrar
  • Associate Producer: Emily Orr

For Educators

Introduction

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.

Lesson Plan 1: First Steps Toward Healing the Ozone
Overview

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.

Objectives

Students will:

  • Analyze data to determine trends in atmospheric ozone from 1979 to today.
  • Establish a timeline of events related to ozone depletion and repair.
  • Communicate to a wide audience the relationship between data collected and societal actions.
Essential questions
  • How do human actions affect the environment? 
  • How can data be used to leverage action to solve political, social and economic problems?
Standards

Next Generation Science Standards

  • MS-PS1-1 Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms. 
  • MS-PS-2&3: Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it. 
  • HS-PS1-3: The structure and interactions of matter at the bulk scale are determined by electrical forces within and between atoms. 
  • Science and Engineering Practices
    • Analyzing & interpreting data
    • Engaging in argument from evidence
    • Obtaining, evaluating and communicating information

C3 Framework

  • D3.1.6-8. Gather relevant information from multiple sources while using the origin, authority, structure, context, and corroborative value of the sources to guide selection
  • D3.3.6-8. Identify evidence that draws information from multiple sources to support claims, noting evidentiary limitations
  • D4.1.6-8. Construct arguments using claims and evidence from multiple sources, while acknowledging the strengths and limitations of the arguments.
  • D4.1.9-12. Construct arguments using precise and knowledgeable claims, with evidence from multiple sources, while acknowledging counterclaims and evidentiary weaknesses.
Lesson Plan 2: Cabinet Simulation for Environmental Policy
Overview

United Nations member states are developing a resolution to end plastic pollution through an international agreement. This type of multilateral environmental agreement has been reached before, notably with the Montreal Protocol in 1987. That agreement, one of very few to achieve universal ratification, regulates the production and use of chemicals known to deplete the ozone layer.

Objectives

Students will:

  • Investigate environmental issues from multiple perspectives and consider stakeholder interests.
  • Examine a key environmental debate and analyze possible solutions to determine their advantages and drawbacks.
  • Create a policy recommendation and engage in a collaborative discussion to debate policy proposals.
Essential questions
  • How have countries, individually and collectively, dealt with environmental challenges?
  • How does the United States government make policy decisions, including those with international consequences?
  • What possible solutions are there to dealing with plastic pollution?
Standards

College, Career, and Civic Life (C3) Framework for Social Studies

  • D1.5.9-12. Determine the kinds of sources that will be helpful in answering compelling and supporting questions, taking into consideration multiple points of view represented in the sources, the types of sources available, and the potential uses of the sources.
  • ​​D2.Civ.3.9-12. Analyze the impact of constitutions, laws, treaties, and international agreements on the maintenance of national and international order.
  • D2.Civ.5.9-12. Evaluate citizens’ and institutions’ effectiveness in addressing social and political problems at the local, state, tribal, national, and/or international level.
  • D2.Civ.6.9-12. Critique relationships among governments, civil societies, and economic markets.
  • D2.Civ.7.9-12. Apply civic virtues and democratic principles when working with others.
  • D2.Civ.9.9-12. Use appropriate deliberative processes in multiple settings.
  • D2.Civ.11.9-12. Evaluate multiple procedures for making governmental decisions at the local, state, national, and international levels in terms of the civic purposes achieved.
  • D2.Civ.13.9-12. Evaluate public policies in terms of intended and unintended outcomes, and related consequences. 
  • D2.His.5.9-12. Analyze how historical contexts shaped and continue to shape people’s perspectives.
  • D2.His.12.9-12. Use questions generated about multiple historical sources to pursue further inquiry and investigate additional sources.
  • D3.1.9-12. Gather relevant information from multiple sources representing a wide range of views while using the origin, authority, structure, context, and corroborative value of the sources to guide the selection.
  • D4.1.9-12. Construct arguments using precise and knowledgeable claims, with evidence from multiple sources, while acknowledging counterclaims and evidentiary weaknesses. 

Common Core Literacy Standards

  • CCSS.ELA-LITERACY.RH.11-12.2 Determine the central ideas or information of a primary or secondary source; provide an accurate summary that makes clear the relationships among the key details and ideas.
  • CCSS.ELA-LITERACY.RH.11-12.3 Evaluate various explanations for actions or events and determine which explanation best accords with textual evidence, acknowledging where the text leaves matters uncertain.
  • CCSS.ELA-LITERACY.RH.11-12.7 Integrate and evaluate multiple sources of information presented in diverse formats and media (e.g., visually, quantitatively, as well as in words) in order to address a question or solve a problem.
  • CCSS.ELA-LITERACY.RH.11-12.9 Integrate information from diverse sources, both primary and secondary, into a coherent understanding of an idea or event, noting discrepancies among sources.
Lesson Plan 3: Exploring Environmental Issues and Solutions
Overview

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 a 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 create and ratify the Montreal Protocol. This collaborative effort has shown promise, with scientists announcing that the ozone layer is beginning to heal. In this lesson, students will examine a modern-day environmental issue and formulate a proposal to address it, composing an original work of creative writing to synthesize their learning.

Objectives

Students will:

  • Examine a modern-day environmental issue.
  • Formulate a proposal to address a modern-day environmental issue.
  • Compose an original work of creative writing.
Essential questions
  • How can we address environmental problems?
  • In what ways do proposals designed to address modern-day environmental issues affect society?
Standards

Common Core Literacy Standards

  • RI 6-12.6-8 Integrate information presented in different media or formats (e.g., visually, quantitatively) as well as in words to develop a coherent understanding of a topic or issue.
  • W 6-12.6-8 Conduct short research projects to answer a question, drawing on several sources and refocusing the inquiry when appropriate.
  • W 6-12.3 Write narratives to develop real or imagined experiences or events using effective technique, relevant descriptive details, and well-structured event sequences.
  • RI.9-10.2 Determine a central idea of a text and analyze its development over the course of the text, including how it emerges and is shaped and refined by specific details; provide an objective summary of the text.
  • W 6-12.9:Draw evidence from literary or informational texts to support analysis, reflection, and research.

College, Career, and Civic Life (C3) Framework for Social Studies

  • D2.Civ.12.6-8. Assess specific rules and laws (both actual and proposed) as means of addressing public problems.
  • D2.Civ.13.6-8. Analyze the purposes, implementation, and consequences of public policies in multiple settings.
  • D2.Civ.13.9-12. Evaluate public policies in terms of intended and unintended outcomes, and related consequences.
  • D3.3.6-8. Identify evidence that draws information from multiple sources to support claims, noting evidentiary limitations.
  • D4.1.6-8. Construct arguments using claims and evidence from multiple sources, while acknowledging the strengths and limitations of the arguments.