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

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.

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.

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.

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.

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.

In 2025, UK scientists began studying climate data from a 1.5-million-year-old ice core

The Antarctica sample will be melted and analyzed in Cambridge to learn about prehistoric environmental conditions. Researchers hope the ice core reveals how Earth's glacial cycles shifted dramatically around 800,000 years ago.

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.

Hear firsthand how scientists and policymakers saved the ozone layer

In this episode, atmospheric chemist Susan Solomon and Protocol architect Stephen Andersen recount how scientific discovery, diplomacy, and public pressure drove the Montreal Protocol—and share lessons for tackling climate change.

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.

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.

The Southern Ocean features the Antarctic Circumpolar Current—the largest ocean current on Earth—which encircles Antarctica and creates a unique biogeographical zone.

Oxygen and ozone molecules absorb up to 99.9% of UV radiation reaching Earth

Although they make up no more than 10 out of every million molecules in the ozone layer, ozone provides outsized protection by absorbing the most energetic wavelengths of ultraviolet radiation. This absorption increases thermal energy in the stratosphere, causing temperatures there to rise with altitude.

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.

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.

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.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Instabilities in the polar jet stream can bring cold Arctic air southward

The polar jet stream marks the boundary between mid-latitude air and the much colder polar air, which are normally contained by the polar vortex—a ring of strong winds that circles the Arctic around 16 to 50 kilometers (10 to 30 miles) above the Earth's surface. Climate change may be responsible for "blocking patterns" that distort the jet stream, allowing polar air to leak into lower latitudes.

The Antarctic Circumpolar Current is Earth's most powerful ocean current and carries more than 100 times the combined flow of all Earth's rivers.

Search for psychrotolerant and psychrophilic microorganisms found in Antarctica

Developed following a five-week expedition to the southern continent, "Life Under the Ice" allows users to examine a petri-dish-like microscopic world and uncover recordings of organisms that can withstand, or even thrive, in the harsh environment.

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.

The British Antarctic Survey created a map of what Antarctica would look like if it lost all 27 million cubic kilometers (6.5 million cubic miles) of its ice—enough to fill almost 6,500 Grand Canyons.

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.

A breakdown of Earth's atmospheric layers, including why it can get colder or hotter with altitude

Gases in the troposphere—the atmosphere's lowest layer—cool with increasing height as they get farther from the thermal energy emitted by Earth's warm surface. In the next layer—the stratosphere—ozone is increasingly heated by the sun's ultraviolet radiation with height. Because cooler air sinks and hotter air rises, the cooler troposphere and hotter stratosphere form a natural boundary keeping Earth's weather in the lowest layer.

Climate data is monitored globally using tools from satellites to backyard gauges

Scientists use satellites, balloons, ocean buoys, and land-based instruments to track climate variables like temperature, precipitation, and wind. These tools gather data from deep ocean waters to the upper atmosphere.

Studying the circadian clock of a tiny swimming polar creature may help forecast polar ecosystem health

A 2025 study found that Antarctic krill, a food chain staple in the Southern Ocean, have an internal biological clock that helps regulate its swimming patterns and helps the tiny shrimp-like animals adapt to daily and seasonal environmental changes. Better understanding of how the clock and light cues interact may help scientists understand how well the species will respond to pronounced climate change in the polar region.

The Arctic warms more quickly than the rest of the planet because of the loss of surface ice, a lack of vertical air circulation, and the release of thermal energy as water vapor condenses.

The ocean's ability to store carbon long-term is being hindered by marine heatwaves

More than 4,000 robotic floats with biogeochemical data sensors, including oxygen, pH, nitrate, suspended particles, chlorophyll, temperature, and conductivity, have been deployed as part of the Global Ocean Biogeochemical Array. They have identified changes to ecosystem structure affecting the ocean's ability to transport carbon from surface waters into the deep.

How glaciers melt

Greenland and Antarctica are home to most of the world's glacial ice, including its only two ice sheets, making them areas of particular interest to scientists. Watch this three-minute video to learn why understanding them is not just interesting, but crucial to our near-term adaptability and our long term survival in a changing world.

The history of Earth's breathable atmosphere, made possible by photosynthetic bacteria

Between 3.2 billion and 2.8 billion years ago, threadlike microorganisms called cyanobacteria began consuming available water vapor, carbon dioxide, and sunlight to produce oxygen. However, molecules released from Earth's interior by volcanoes consumed this oxygen via chemical reactions, preventing it from accumulating until volcanism had sufficiently decreased about 2.4 billion years ago.

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.

Scientists use climate proxies—physical, chemical, and biological materials preserved in sediments, ice, and fossils—to infer historical climate data and determine past climate patterns.

Validation of the greenhouse effect may have been misattributed

Although Irish physicist John Tyndall showed in 1859 that water vapor and carbon dioxide could absorb and radiate infrared radiation, experiments by American scientist Eunice Foote three years earlier identified the same phenomenon for light in general. Historically overshadowed, her work was rediscovered by female historians over a century later.

Antimatter was discovered by examining debris from collisions between atmospheric gases and cosmic rays—high-energy matter particles from space.

Solar eclipses block the sun enough to enable scientists to observe its faint outer atmosphere, or corona, whose spectrum led to the discovery of helium over a decade before it was identified on Earth.

Excluding water vapor, greenhouse gases make up less than 1% of Earth's atmosphere

Although carbon dioxide, methane, nitrous oxide, ozone, and most fluorinated gases account for only a minority of the planet's greenhouse effect due to their lower concentrations, they are more effective at trapping thermal radiation. While water vapor condenses within two weeks, other greenhouse gases linger in the atmosphere for years on average.

Watch a visualization of how Earth's oceans impact its atmosphere, weather, and climate.

The field of attribution science seeks to determine whether specific phenomena, such as melting glaciers, droughts, and hurricanes, are driven by Earth's natural climate cycles or by human-caused climate change.

Greenhouse gas concentrations can be measured using spectroscopy

Each type of greenhouse gas absorbs a distinct set of wavelengths of light, which serve as a unique spectral signature. By shining light through an atmospheric sample and measuring the light on the other side, the amount of each gas can be calculated from the amount of missing light.

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.

Low temperatures led to the equipment failure that caused the Challenger disaster

The polymer chains that make up an O-ring give it the ability to quickly deform and fill in gaps to seal fluids, including the hot gases from the Challenger's rocket boosters. Cold weather on the day of launch stiffened the O-rings, reducing their flexibility and sealing properties.

Britain’s bottle innovation saved Champagne

Champagne wouldn’t be where it is today without a surprising partner: 17th-century British glassmakers. An energy crisis caused by deforestation—not enough trees to burn—led to the search for an alternative fuel source. Enter coal. The plentiful resource burned much hotter than wood, creating stronger glass that could stand up to the pressure of the carbon monoxide produced by the wine’s second fermentation and solving one of the fledgling industry’s most vexing problems.

A remote Scottish island is awash in forever chemicals even though there are no obvious industrial sources nearby, and scientists suspect the toxic substances are accumulating via sea spray.

Scientists determine the smells of objects in outer space

Using spectrographic techniques, scientists determine the chemical composition of planetary atmospheres, comets, and other objects in space. Combining these chemicals in labs on Earth has revealed locations in space that smell like nail polish remover, rotten fish, and urine.

The robust wine production of Antarctica

Antarctica might not be known for its agriculture, but parts of its unique climate are suitable for growing wine grapes. Most of the wine produced there is icewine, a style of dessert wine commonly found in Canada and Germany. This guide covers Antarctica’s unique soil composition, grape varieties, and how exactly penguins contribute to this unusual wine-growing region. There’s even a recommendation for an Antarctic tasting room for adventurous souls.

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.)

How the loss of Earth's atmosphere would cause oceans to boil at freezing temperatures

Many phenomena requiring air pressure, from the flight of birds and aircraft to the act of breathing, would no longer be possible. Because sound travels through vibrating air molecules, the loss of the planet's atmosphere would also create a silent environment. Even during daytime hours, the sky would resemble a clear night sky.

Arctic permafrost may store twice as much carbon as the entire atmosphere

Rising greenhouse gas concentrations are expected to continue to increase average global temperatures and threaten to thaw ground that has been frozen for thousands of years. The release of greenhouse gases from remnant organic matter would exacerbate the greenhouse effect, creating a positive feedback loop.

Cosmic rays can be detected using cloud chambers—containers where alcohol vapor condenses around trails of ions created by these high-speed particles from space.