The Greenhouse Effect on Earth

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Earth’s atmosphere is slightly warmer than what it should be due to direct solar heating because of a mild case of greenhouse effect…

The ground is heated by visible and (some) infrared light from the Sun.

The heated surface emits infrared light.

The majority of Earth’s atmosphere (N2 and O2) are not good greenhouse gas.

The small amount of greenhouse gases (H2O, CO2) traps (absorb and re-emit) the infrared radiation, increasing the temperature of the atmosphere…

Greenhouse Gases

The primary components of Earth’s atmosphere, N2 and O2 do not have absorption in the IR wavelength range, therefore, do not have a significant role in setting the surface temperature of the planet…

Greenhouse gas are efficient in absorbing IR light…
The most important greenhouse gases are:
H2O – Water vapor.
CO2 – Carbon Dioxide
CH4 – methane

Feedback Loop

Positive Feedback
Mechanisms that make things worse…
e.g., Increasing CO2 in the atmosphere leading to the release of more CO2

Negative Feedback
Mechanisms that are self-correcting…
e.g., Increasing CO2 in the atmosphere leading to higher rate of CO2 removal, such as our CO2 cycle.