Which gas is known for protecting the Earth's surface from harmful UV rays when found in the upper atmosphere?

Ozone is a gas that plays a critical role in protecting the Earth's surface from harmful ultraviolet (UV) radiation when it is present in the upper atmosphere, specifically in the ozone layer. This layer, located in the stratosphere, absorbs a significant portion of the sun's harmful UV radiation, thereby reducing the risk of skin cancer, cataracts, and other health issues in humans, as well as protecting ecosystems from damage caused by increased UV exposure.

The presence of ozone in the atmosphere is essential as it acts as a shield, absorbing UV-B and UV-C rays, which are particularly harmful. This protective function is vital for maintaining life on Earth as it helps preserve the integrity of biological processes affected by UV radiation.

In comparison, carbon dioxide and nitrous oxide do not provide this specific protective function against UV radiation. Instead, they are greenhouse gases that contribute to climate change by trapping heat in the atmosphere. Methane, while also a greenhouse gas, does not offer the same protective benefits against UV rays as ozone does. This makes ozone unique in its protective capacity against UV radiation, highlighting the importance of maintaining the ozone layer for environmental and health reasons.