History of Earth the third atmosphere, rich in oxygen, emerged when bacteria began to produce oxygen about 2.8 Ga. In early models for the formation of the atmosphere and ocean, the second atmosphere was formed by outgassing of volatiles from the Earth's interior. Now it is considered likely that many of the volatiles were delivered during accretion by a process known as "impact degassing" in which incoming bodies vaporize on impact. The ocean and atmosphere would, therefore, have started to form even as the Earth formed. The new atmosphere probably contained water vapor, carbon dioxide, nitrogen, and smaller amounts of other gases. Planetesimals
Greenhouse gas footprint and constant deforestation, the amount of greenhouse gas in the atmosphere is increasing, which makes reducing a greenhouse gas footprint harder to achieve. However, there are several ways to reduce one's greenhouse gas footprint, such as using more energy efficient household appliances, increase usage of fuel efficient cars, and saving electricity. Greenhouse gases (GHGs) are gases that increase the temperature of the Earth due to their absorption of infrared radiation. Although some emissions are natural, the rate of which they are being produced has increased because of humans. These gases are emitted from fossil fuel usage in electricity, in heat