How does the hole in the ozone layer affect global warming?
The hole in the upper ozone layer (stratosphere) causes cooling, because ozone itself is a greenhouse gas. However, ozone is needed in the stratosphere, where it occurs naturally to filter out harmful ultraviolet radiation. Ozone in the lower atmosphere (troposphere) is caused by pollutants. Ozone in the troposphere is a danger to human health, because it can cause lung damage and other cardio-pulmonary problems when breathed. Substances that deplete ozone in the stratosphere are regulated under the Montreal Protocol (see glossary). Ozone in the troposphere is regulated by the Clean Air Act.
