Hear firsthand how scientists and policymakers saved the ozone layer

Go inside the global effort that led to the Montreal Protocol in this narrative podcast

Nobel laureate Mario Molina and other key voices recount how science and diplomacy converged to develop a plan to close the ozone hole, offering insight into history's most successful environmental treaty.

Watch a 1986 television special about the discovery of the ozone hole

The groundbreaking discovery of the Antarctic ozone hole in the mid-1980s marked a critical turning point, galvanizing international action to address the ozone-depleting properties of chlorofluorocarbons, which had been identified about a decade earlier. This environmental crisis was brought vividly to public attention through media pieces like this one.

The history of the Montreal Protocol, the only universally ratified treaty in UN history

Mario Molina and F. Sherwood Rowland discovered that chlorofluorocarbons released chlorine atoms that could break down molecules making up the protective ozone layer. Despite attempts to discredit scientists and economic concerns raised by politicians, the agreement to phase out ozone-depleting substances was signed in 1987.

How amendments to the Montreal Protocol have expanded global ozone protections

Since 1990, five major amendments—London, Copenhagen, Montreal, Beijing, and Kigali—have accelerated chemical phase-outs, added new substances, such as hydrochlorofluorocarbons, and tightened enforcement.

How scientists earned themselves a Nobel Prize by discovering what destroyed ozone

In 1974, chemists Mario Molina and F. Sherwood Rowland showed that chlorofluorocarbons—then used as aerosol propellants, refrigerants, and industrial solvents—rise into the stratosphere and, upon being struck by ultraviolet radiation, release chlorine atoms, which break apart ozone molecules. Their work earned them the Nobel Prize in chemistry in 1995.

The Montreal Protocol helped prevent significant quantities of greenhouse gas emissions

By phasing out ozone-depleting chemicals between 1990 and 2010, the Montreal Protocol prevented emissions equal to 135 gigatons of CO₂—avoiding an estimated 0.5 to 1 degrees Celsius of additional global warming by 2100.

How a skin cancerous growth shifted an initially skeptical President Reagan on the ozone crisis

While a 1985 Nature study revealing the Antarctic ozone hole jolted public concern, Reagan's administration was more focused on the Cold War than on environmental policy. His health scare and the market potential for developing alternatives to chlorofluorocarbons helped turn the tide, leading to the Montreal Protocol's unanimous ratification by a bipartisan Senate in 1988.

Learn why the Montreal Protocol may help prevent millions of cancer deaths

By restoring the ozone layer and reducing ultraviolet exposure, full implementation of the Montreal Protocol is expected to prevent about 443 million cases of skin cancer, 2.3 million skin cancer deaths, and 63 million cases of cataracts among Americans born from 1890 to 2100.

The ozone layer is on track to recover to pre-1980 levels by mid-century

Thanks to the Montreal Protocol, the ozone layer is steadily recovering and, according to a 2022 assessment, is expected to return to 1980 levels by 2040 globally, 2045 over the Arctic, and 2066 over Antarctica.

View when each UN member signed the Montreal Protocol

Adopted in 1987 to phase out ozone-depleting substances, the agreement achieved universal ratification by all 197 UN member states, making it the first and only such international treaty in the UN's history.

How a black market for banned refrigerants still threatens ozone recovery and climate progress

Despite the Montreal Protocol's success, illegal trade in chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons persists. Driven by high profits and weak enforcement, smugglers supply banned refrigerants, causing significant ozone depletion and greenhouse gas emissions equivalent to billions of tons of carbon dioxide.

How the Montreal Protocol supported developing nations in phasing out ozone-depleting substances

Established in 1991, the Multilateral Fund for the Montreal Protocol finances developing nations' transition to cleaner technologies. It has disbursed more than $4B across more than 140 countries and was the first financial mechanism created under an international treaty.

Why the Antarctic climate enabled British scientists to discover the ozone hole

In the Antarctic stratosphere, polar conditions facilitate the formation of polar stratospheric clouds, which allow chlorine compounds from chlorofluorocarbons to accumulate. In 1985, British Antarctic Survey scientists detected massive springtime losses over Antarctica, as accumulated compounds destroyed significant amounts of ozone once sunlight returned.

Why a Montreal Protocol amendment cut back on the replacements for CFCs

Hydrofluorocarbons were introduced in the 1990s as ozone-safe substitutes for chlorofluorocarbons and hydrochlorofluorocarbons. However, scientists later found that they trap thousands of times more thermal energy in the atmosphere than carbon dioxide does, prompting a 2016 amendment to the Protocol to phase them out.

Listen to a reporter discuss his story spotlighting a decadeslong corporate cover-up about forever chemicals, substances, which can persist in the environment for hundreds of years—though not forever.

Discovering how the dinosaurs went extinct may have helped avert nuclear war

This NPR Throughline episode explains how the 1980 discovery that an asteroid-driven dust cloud killed the dinosaurs inspired Cold War scientists' fears of "nuclear winter"—a sunlight-blocking aftermath of nuclear war that may have discouraged leaders from launching one.

Climate science 101: climate change, its impacts, and potential solutions

How do we know that this warming is happening and that it’s caused by humans? How strong is the evidence? What risks can we expect and what can we do about them?

A four-part podcast traces how the Manhattan Project reshaped the world

This podcast series explores the origins of the Manhattan Project, its secret cities, and the scientists behind it—showing how the effort contributed to the end of World War II, launched the Atomic Age, and later led Oppenheimer to become a critic of nuclear weapons.

How sunlight helps chlorofluorocarbons destroy the ozone molecules that block solar radiation

CFCs, which are used in old refrigerants, air conditioners, and aerosol sprays, do not react with atmospheric molecules. Once they reach the stratosphere, ultraviolet radiation breaks chlorine atoms off of them, which can each break apart more than 100,000 ozone molecules, thinning Earth's protective layer against ultraviolet radiation.

Why the ozone hole altered Southern Hemisphere jet streams and rainfall patterns

Ozone depletion over Antarctica shifted jet streams southward, drying Australia while increasing rainfall in Uruguay, Brazil, Paraguay, and Argentina. Around the turn of the millennium, these trends began to slow as the Montreal Protocol phased out ozone-depleting substances.

Ozone protects against the sun's UV radiation and enhances the greenhouse effect

In the stratosphere, trioxygen molecules can absorb harmful ultraviolet radiation from the sun, preventing it from reaching Earth's surface, where it can harm organisms and raise surface temperatures. In the lower atmosphere, ozone acts as a greenhouse gas, trapping thermal radiation.

Explore a series of interdisciplinary explainers on climate science

From animations on the quantum mechanics of greenhouse gases to a photo essay on how scientists acquire climate data, this collection provides detailed explorations of how different branches of science have contributed to our understanding of climatology.

Track the current size of the Antarctic ozone hole with NASA's real-time data

NASA's Ozone Watch provides daily satellite images and time-lapse videos showing the extent of the Antarctic ozone hole. Each spring, scientists monitor its size and depth to measure recovery progress and detect any new chemical or climatic disruptions.

Hear how the first moon landing was saved

This podcast series explores Apollo 11 through firsthand stories from the engineers, mission controllers, and astronauts who made the moon landing possible, culminating in 13 minutes of NASA archive audio leading up to the landing.

National Geographic presents how to protect the oceans

What can we do to protect and preserve the world's oceans? Be inspired by spectacular wildlife footage from National Geographic while learning key strategies.

Large oil companies knew about the impact of carbon emissions since the ’70s

PBS Frontline’s The Power of Big Oil reveals how industry giants like Exxon and Shell were researching climate change in the 1970s but then funded denial campaigns—using internal science to sow public doubt for decades.

Fluorinated molecules are the most impactful, longest-lasting greenhouse gases

Developed as replacements for ozone-depleting substances in refrigeration and air conditioning systems, these compounds are released through leaks in and ongoing use of these appliances, as well as from various industrial processes. They can remain in the atmosphere for thousands of years and have warming potentials that are a thousand to tens of thousands of times greater than those of carbon dioxide.

How Big Oil misled the public into believing plastic would be recycled

An NPR and PBS Frontline investigation reveals how the oil and gas industry used the promise of recycling to sell more plastic, even when they knew it would never work on a large scale.

Pineapple research helped scientists solve Los Angeles' smog mystery

In the 1950s, chemist Arie Haagen-Smit applied methods he'd used studying pineapple plant chemistry to smog-filled air—discovering that sunlight reacting with car exhaust produced photochemical smog from hydrocarbons and nitrogen oxides, not factory smoke.

How the Montreal Protocol made CFCs the most valuable Miami contraband after cocaine

Following the 1990s production ban, smugglers flooded Miami with illegal chlorofluorocarbons used in air conditioning. A 15-kilogram cylinder bought for $70 in Europe could sell for $242 in the US, fueling multimillion-dollar black-market trade. (Some users may experience a paywall.)

Oil's legacy: fueling industrial growth and shaping imperial strategies

This episode of The Rest Is History podcast traces oil's pivotal role—from fueling industrial growth to steering imperial power. It also examines how access to oil shaped US politics, World War II, and sparked the creation of OPEC following the Suez Crisis.

Tracing the history of refrigeration

Refrigeration has become critical to most of our lives. But not long ago, it wasn't available. How did we become so dependent on our fridges and freezers? This fun, informative podcast traces the history of keeping it cool with ice and...

Founder of The Ocean Cleanup explains the case for cleaning oceans

Removing trash from the oceans not only saves wildlife, it may save human lives, too. The CEO and founder of The Ocean Cleanup explains how existing plastic pollution harms us and get harder to clean up over time.

The Keep America Beautiful campaign shifted the blame for litter from manufacturers to individuals

This podcast examines how one organization reshaped the American public's relationship with recycling, asking why responsibility for a cleaner environment falls to individuals rather than to the companies that produce waste.

Revelations that apples were sprayed with the chemical Alar led to its ban in the 1980s

Almost three decades after Rachel Carson’s “Silent Spring,” a “60 Minutes” segment on the use of Alar, a chemical sprayed on apples, drew national attention and inspired supermarkets and schools to remove apples from their shelves and cafeterias. That same year, the Environmental Protection Agency took action against the use of the chemical in food.

Impact of Brazil's politics on the Amazon rainforest

In this seven-minute podcast, Andrew Limbong speaks with environmental researcher Erika Berenguer about Brazilian President Luiz Inácio Lula da Silva’s ambitions to save the Amazon Rainforest from deforestation.

NASA satellite data and sound recordings used to assess rainforest health

This two-minute video describes the work of scientists who are analyzing the impact of repeated forest fires in the Amazon by recording the unique sounds in degraded forests. The team is using acoustic sensors to record sounds of wildlife in the...

The dramatic story of the spies and scientists behind the atomic bomb

This podcast traces the dramatic origins of nuclear weapons—from the scientists racing to beat the Nazis in Season 1 to the Soviet spy who stole atomic secrets in Season 2.

Climate change skepticism and business interests politicized environmental protection

The EPA was created under a Republican administration with bipartisan support in response to overwhelming public demand during a time of visible pollution and environmental crises. Beginning with President Reagan, the agency was recast as burdensome, and environmental regulations have been gradually rolled back.

Modern Marvels examines the Manhattan Project

This episode of the television program 'Modern Marvels' focuses on the Manhattan Project, combining archival footage and interviews with historians and scientists to shed light on one of the most ambitious military and scientific endeavors in human history.

Scientists from the frontline discuss the future of antibiotics and superbugs

Superbugs are a very real problem, but researchers around the world are working to advance our understanding of these pathogens and develop new medicines. This podcast talks with several scientists on the frontier of superbug research, offering insight into what we know—and what the future of medicine may look like.

Bill Nye believes a World War II-level mobilization is needed to end climate change

As part of his science advocacy efforts, Nye has argued that existing technologies, including electric vehicles and renewable energy, can already significantly reduce emissions. However, switching to these technologies requires a more expansive awareness of the problem and a greater sociopolitical willingness by policymakers and the general public.

Why Earth would become a more deadly environment without the ozone layer

The ozone layer blocks almost all of the sun's harmful, including dangerous UVC rays that can damage cells by breaking chemical bonds. Without it, rates of skin cancer, crop failures, oceanic die-offs, and widespread ecosystem collapse would increase significantly, making Earth largely uninhabitable.

The weather time machine

A fun interactive on how old ships’ logs are giving scientists new insights into the past and future of the Earth’s changing climate (w/maps and pictures).

Go behind the scenes of Davos with ‘60 Minutes’

In 2010, "60 Minutes" gained rare, near-unprecedented access to the World Economic Forum, with Scott Pelley roaming Davos’ exclusive meetings and elite spaces. See how global power brokers mingle, negotiate, and shape agendas offstage at the event.

The EPA partners with other countries to strengthen environmental protection

Through bilateral programs on every continent, the EPA shares American environmental expertise with developing nations and economies in transition. These partnerships support air and water protection, chemical safety, and pollution control, while advancing US environmental priorities abroad.

How is the climate like baseball?

A two-minute video taking a lighthearted look at an unexpected analogy, explaining why some people call carbon dioxide (and the other greenhouse gases) the steroids of the climate system.

Explore the history of antibiotics with 'This Podcast Will Kill You'

The show blends medical history with storytelling and science. In Episode 50, the hosts trace the dramatic origins of antibiotics—from Fleming's moldy petri dish to Florey's wartime labs—and explore their lasting impact on health.

The secret lives of cells

Cutting-edge microscopy has revealed previously unseen interactions of biological molecules within their cellular environment, enabling scientists to observe and analyze the molecules in a holistic view. This podcast explains the minute advancements made over the last few decades in observing cells, revealing how scientists have come and what the future holds for the field.

Unlike America's recommendations, Australian authorities don't encourage routine sunscreen use for darker skin tones—reasoning that melanoma risk is low, and it's better to get UV exposure to help the body naturally produce vitamin D.