One causes

One of the main causes of global warming is (NASA) National Aeronautics and Space Administration.
Scientists have found that a major form of global air pollution involved in summertime "smog" has also played a significant role in warming the arctic, it will first and foremost affect the ozone layer.
The Ozone layer plays several different roles in the Earth’s atmosphere. In the high-altitude region of the stratosphere, ozone acts to shield the planet from harmful ultraviolet radiation. In the lower portion of the atmosphere (the troposphere), ozone can damage human health. The damage of Ozone is also a greenhouse gas and it can be harmful to contribute to global warming.