The evolution of Earth's atmosphere over billions of years transformed our planet from a hostile environment to one capable of sustaining complex life. This remarkable journey involved volcanic activity, the emergence of primitive life forms, and dramatic changes in atmospheric composition.
- Initial atmosphere primarily contained carbon dioxide, water vapor, and nitrogen from volcanic emissions
- Historical air composition through polar ice analysis reveals relatively stable conditions over the past 200 million years
- The role of algae in oxygen production in early Earth was crucial, contributing to 90% of atmospheric oxygen
- Carbon dioxide levels decreased through various natural processes including ocean absorption and photosynthesis
- Modern atmosphere consists of 78% nitrogen, 21% oxygen, and small amounts of other gases