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How does ozone in the upper atmosphere help protect life on Earth?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — oxygen group element Modern version of the periodic table of the elements (printable).

The ozone layer, located in the stratosphere, acts as a vital protective blanket for life on Earth by absorbing the Sun's harmful ultraviolet (UV) radiation.123

By screening out lethal levels of radiation—specifically wavelengths less than 290 nm—the ozone layer prevents this energy from reaching the surface, where it could otherwise injure or kill most living organisms. This protective function is essential because excessive UV exposure is linked to severe health risks, including skin cancer, eye cataracts, and damage to immune systems and genetic material.2345

Historically, the formation of this layer was a critical milestone in the development of life, as it allowed marine organisms to safely migrate from the oceans onto land. Today, maintaining the integrity of this layer remains a global priority, as the depletion of stratospheric ozone increases the amount of damaging radiation that reaches the surface, threatening both human health and broader ecosystems.125