Earth's Atmospheric Evolution and Human Impact

📋 Course Outline

1. Early Atmosphere Composition
2. Formation of Oceans
3. Carbon Dioxide Cycle
4. Photosynthesis Impact
5. Fossil Fuel Formation
6. Oxygen Level Increase
7. Human Impact on Atmosphere
8. Uncertainty in Atmospheric History

📖 1. Early Atmosphere Composition

🔑 Key Concepts & Definitions

• Early Atmosphere: The original mixture of gases surrounding Earth shortly after its formation, approximately 4.6 billion years ago.
• Greenhouse Gases: Gases that trap heat in the atmosphere, such as carbon dioxide (CO₂) and methane (CH₄), which contributed to Earth's initial high temperatures.
• Volcanic Outgassing: The release of gases like CO₂, water vapour, nitrogen, ammonia, and methane from Earth's interior through volcanic eruptions.
• Photosynthesis: Biological process carried out by cyanobacteria and plants that converts carbon dioxide and water into oxygen and glucose, reducing CO₂ levels.
• Sedimentary Rocks: Rocks formed from the accumulation and compression of mineral and organic particles, often containing carbonates that lock up CO₂.
• Fossil Fuels: Carbon-rich energy sources like coal, oil, and natural gas formed over millions of years from the remains of dead plants and marine organisms.

📝 Essential Points