The ozone layer is vital because it acts like Earth’s sunscreen, blocking most of the Sun’s harmful ultraviolet (UV) radiation and making the planet habitable for living things.

Protection from UV radiation

The ozone layer in the stratosphere absorbs the majority of incoming UV‑B and UV‑C rays, which are the most biologically damaging parts of sunlight. Without this shield, far more high‑energy radiation would reach Earth’s surface and penetrate living tissues.

Human health benefits

By filtering out most dangerous UV radiation, the ozone layer greatly reduces rates of skin cancer, cataracts, and damage to the immune system. If the ozone layer thins, these health problems increase because more intense UV reaches people on the ground.

Protection of ecosystems

Excess UV damages the DNA and cellular machinery of many organisms, from tiny plankton in the oceans to plants on land. Stronger UV can disrupt food chains, reduce crop yields, and harm aquatic life near the water’s surface, which forms the base of many marine ecosystems.

Climate and environmental role

Stratospheric ozone helps control the temperature structure of the upper atmosphere, influencing weather and circulation patterns. Changes in the ozone layer can therefore affect climate and environmental conditions in complex ways.

Good ozone vs bad ozone

Ozone high in the stratosphere is “good” because it protects life, while ozone near the surface is “bad” when present in excess, acting as an air pollutant that harms lungs and reduces plant growth. Protecting stratospheric ozone while limiting surface ozone pollution is essential for a healthy environment.