Atmosphere
Ozone Layer
The region of the stratosphere with high ozone concentration that absorbs most of the Sun's harmful ultraviolet radiation.
Definition
The ozone layer is the part of Earth's stratosphere, roughly 15 to 35 kilometres above the surface, containing a relatively high concentration of ozone (O₃). It absorbs most incoming ultraviolet-B and ultraviolet-C radiation, shielding life on land and in surface waters from DNA-damaging exposure.
References
layer function, depletion and recovery projections
ozone hole observations
Overview
What it means
In the 1980s scientists documented severe seasonal ozone loss over Antarctica — the ozone hole — caused by chlorine and bromine from ozone-depleting substances. The Montreal Protocol's controls halted the decline; the layer is recovering, with full recovery over most of the globe expected around the middle of this century.
How it is used
The term anchors ozone science and policy communication, World Ozone Day (16 September), and ongoing WMO/UNEP scientific assessments of ozone depletion published every four years.
Why it matters
The ozone layer's damage and recovery demonstrate both the planetary scale of human impact and the effectiveness of binding global action — the template often invoked for climate cooperation.
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