How does the ozone layer protect living things from ultraviolet radiation?

The ozone layer acts as a vital shield for life on Earth by absorbing the most damaging forms of ultraviolet (UV) radiation from the Sun.123

Located in the stratosphere, this layer effectively blocks nearly all solar radiation with wavelengths shorter than 290 nanometers. By absorbing these high-energy rays, the ozone layer prevents them from reaching the surface, where they would otherwise cause significant injury or death to living organisms. Specifically, it screens out lethal levels of UVB radiation, which is known to damage DNA, harm ecosystems, and negatively impact human health, including increasing the risk of skin cancer and cataracts.234

The formation of this protective barrier was a critical development in the history of our planet, as it allowed life to safely migrate from the oceans onto land. Because intense UV exposure can kill sensitive organisms essential to the food chain, the continued integrity of the ozone layer remains fundamental to the survival of life on Earth.123