What is the term used to describe the thinning of stratospheric ozone over the poles?

The term used to describe the thinning of stratospheric ozone over the poles is "ozone hole." This phenomenon specifically refers to the significant reduction of ozone concentration that occurs in the stratosphere, particularly over Antarctica, during the Southern Hemisphere's spring. The term highlights the area where ozone levels drop dramatically, leading to increased ultraviolet (UV) radiation reaching the Earth's surface.

Ozone depletion is a broader term that encompasses the overall reduction of ozone in the stratosphere, but it does not specifically pinpoint the polar regions or imply the severity that the term "ozone hole" conveys. Ozone thinning is also a general term and is not used to describe the specific and more severe depletion observed over polar regions. Ozone layer collapse implies a complete failure of the ozone layer, which is not accurate since the ozone layer still exists, albeit at lower concentrations in certain areas, especially over the poles. Therefore, "ozone hole" is the most accurate and widely accepted term for this specific phenomenon.