How the ozone layer formed
The ozone layer has been integral to sustaining life on Earth, significantly influencing the development and survival of terrestrial life forms. Without it, most living things we recognise today would not have developed, and the planet's surface would be a far harsher place.
Hundreds of millions of years ago, Earth was limited to simple life forms such as single-celled organisms. The atmosphere lacked the oxygen we depend on. Over time, these early life forms began releasing small amounts of oxygen through photosynthesis. This process continued for millions of years, gradually building up oxygen levels in the atmosphere.
As oxygen accumulated, ultraviolet light from the sun began splitting oxygen molecules (O2) into individual atoms. These atoms then combined with other oxygen molecules to form ozone (O3) in the upper atmosphere. This created a protective shield against the sun's ultraviolet radiation, allowing more complex life to eventually emerge and thrive on land.
The discovery of ozone
Ozone was first identified in 1839 by Christian Schönbein, a Swiss chemist. He was investigating electrical discharges at the time. This is fitting since ozone can be produced by high voltage electrical arcs such as those from spark plugs or arc welders.
Schönbein named the gas ozone, drawing on the Greek word meaning "to smell". The substance has a distinctive sharp odour, often compared to the smell you notice near electrical equipment or after a lightning storm.
While Schönbein recognised the gas, he could not describe its molecular structure. That understanding developed over subsequent decades as scientists determined that ozone consists of three oxygen atoms bonded together. This structure, written as O3, distinguishes ozone from the oxygen we breathe, which contains only two atoms.
Schönbein continued his research and was among the first scientists to suggest that ozone might be present in higher concentrations in the upper atmosphere. This idea would prove correct, though it took decades of further study to confirm.
Your situation may be slightly different. ask a question below ↓ and our editorial team will reply with our advice.
Understanding the ozone layer
By the early twentieth century, scientists had begun measuring ozone in the atmosphere more systematically. Researchers found that ozone concentrations varied with altitude, time of year and location. The highest concentrations sit in the stratosphere, roughly 15 to 35 kilometres above the Earth's surface.
This band of ozone rich air absorbs much of the sun's harmful ultraviolet radiation before it reaches ground level. Without this filtering effect, UV exposure at the surface would be far more intense, posing greater risks to human health and damaging ecosystems.
UK scientists played a notable role in ozone research. In 1985, Joe Farman and his colleagues at the British Antarctic Survey detected dramatic ozone depletion over Antarctica. Their findings helped prompt international action to address the problem.
Why the ozone layer still matters
The discovery that certain chemicals were damaging the ozone layer led to the Montreal Protocol in 1987. This international agreement phased out the production of substances such as chlorofluorocarbons, which were widely used in refrigerators, aerosols and industrial processes. Many of these substances are also potent greenhouse gases, meaning the protocol delivered climate benefits beyond ozone protection.
The protocol is regarded as a significant milestone in environmental policy. Ozone levels have been slowly recovering, though full recovery is not expected until around 2060 to 2070 according to United Nations Environment Programme assessments.
The ozone layer remains a subject of ongoing monitoring. Organisations including the Met Office and the European Space Agency track ozone levels and report on changes. For those wanting to follow the science, the Met Office provides regular updates on atmospheric conditions.
Examining the history of the ozone layer reveals both its vulnerability to human-made chemicals and the success of global policy interventions. The atmosphere can be affected by human activity, but coordinated action can make a measurable difference.
Since 1970 scientists began to suggest that this vital protection from the sun’s radiation could be affected by the actions of mankind.That is what we are experiencing now the world over
Ask Ozone Depletion a question
Ask our editorial team a question and we will reply with our advice. Tell us as much about your situation as you can: the more detail you give, the more useful our answer can be.
You do not need to use your real name. Please do not include your full address, phone number, email address, or the names of other people. We may edit or remove identifying details for privacy and legal reasons.
Comments are moderated before publication.