Earth's atmosphere has undergone drastic changes throughout the course of the planet's history. Initially, the early atmosphere was produced from the degassing of volatile elements of the Earth's interior during its formation. This volatile-rich material was likely present within the primordial Earth's mantle, released through volcanic eruptions. Hydrogen, water vapor, methane, carbon monoxide, and nitrogen are some of the main components that made up the early atmosphere.

As the planet cooled, the water vapor condensed to form oceans, and a significant portion of the carbon dioxide dissolved in the waters, contributing to the development of the early oceans' chemistry. The reducing nature of the primitive atmosphere, with little to no free molecular oxygen, paved the way for the rise of life on Earth, as primitive organisms could harness the readily available energy from inorganic molecules.

Later on, the biological processes led to the transformation of the atmosphere, particularly through photosynthesis performed by cyanobacteria. Oxygen began to accumulate as a byproduct of photosynthesis, leading to the rise of an oxidizing environment. This process of oxygenation eventually led to the oxygen-rich atmosphere we have today, enabling complex life forms to evolve and flourish.