The phrase "delicate balance" implies that Earth's atmosphere is a complex system that is finely tuned to maintain certain conditions necessary for the sustenance of life. It suggests that even small changes to the atmosphere can have significant and potentially harmful consequences.
The atmosphere of Earth is a complex system made up of many different gases, including oxygen, nitrogen, carbon dioxide, and others. These gases interact with one another in ways that are not yet fully understood, but it is clear that they play a critical role in regulating Earth's temperature, protecting it from harmful radiation, and supporting the growth of plant and animal life.
However, human activities such as the burning of fossil fuels and deforestation are altering the composition of the atmosphere, leading to changes in the global climate and other potentially harmful effects. The phrase "delicate balance" emphasizes the idea that even small changes to the atmosphere can have significant and potentially unpredictable consequences, and that it is important to take steps to protect and preserve this vital system.