Earth's Atmosphere
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- 4.5 billion years ago, our earth formed. Hydrogen and Helium were the first gases.
- During the Jurassic Period, the climate was generally warmer by 5 to 10 degrees Celsius, and atmospheric carbon dioxide levels were likely four times higher.
- I experienced the Ice Age. During the ice age, atmospheric carbon dioxide levels were at 180 parts per million, CO2 also became low.
- After the Ice Age, plants became firmly established on land, during the Carboniferous Period. Oxygen made up 20 percent of the atmosphere.
- The Earth cooled down eventually, and much of the carbon dioxide was replaced by oxygen.
- Today, the current composition of the Earth's atmosphere is roughly 80% nitrogen and 20% oxygen.
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