En-en adult card 13 additional greenhouse effect
Card #13: Additional Greenhouse Effect
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The greenhouse effect is a natural phenomenon – and incidentally, the first of the GHGs is water vapor.
Without greenhouse effect, the planet would be 33°C colder and life as we know it would not be possible.
But CO2 and other GHGs related to human activity increase the natural greenhouse effect and unbalance the climate.
Explanation
On this card, we can see arrows of two colours :
- Orange for the energy that comes from the sun (UV, visible light and high-frequency infrared) and that which is reflected by the albedo effect at the same frequency. Albedo is the ability of a body to reflect light (a black body has an albedo of 0, a mirror has an albedo of 1, the earth has an average albedo of 0.31).
- Red for low frequency infrared, emitted by the earth which is less warm than the sun, or retained by the greenhouse effect.
The greenhouse effect is based on the fact that it is not the same incoming radiation as outgoing radiation.
On the right, "-18°C" is the temperature we would have on earth without the greenhouse effect and "15°C" is the actual average temperature today.
It was "14°C" in 1850, i.e. before human activity produced this additional greenhouse effect.
Facilitation tips
This card can be used to explain the greenhouse effect or radiative forcing.
The image of the duvet can be used to explain the additional greenhouse effect: under the duvet you are just fine in terms of temperature, the duvet is the natural greenhouse effect. All the GHGs that man puts into the atmosphere add feathers to the duvet and it gets hotter and hotter.
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