Earth has something that distinguishes it from most celestial bodies, an atmosphere that makes life on our planet possible in the first place. But over 30,000 years ago, we humans started changing the composition of this atmosphere. The discovery of controlled use of fire is a milestone in history, but led to an extreme increase in air pollution from internal combustion engines to power vehicles and from power plants that generate electricity and heat for civilization. The Man-made climate change threatens life in general.