A worldwide effort to heal damage to the ozone layer is showing early progress.
Click here to subscribe to our newslettersHealing the Ozone: First Steps Toward Success
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.
More Like This

Author Rachel Carson’s strike against the pesticide DDT turned her into both an environmental hero and a foil for those who believe regulation has gone too far. That fight is more relevant than ever.

Is geo-engineering the climate an answer to global warming? Cold War science has some lessons.

Catastrophic accidents at power plants have heightened fears about the safety of nuclear energy, but environmentalists and others are giving it renewed attention as a way to fight global warming.

There are now so many wild horses on public land – nearly 100,000 – that they have become caught in a battle between the government, ranchers and environmentalists.