Useful Global Warming figures

[Clairwil]

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Source: The Economist, 2010-03-20

All figures are in watts per square meter

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157 = Space --> Atmosphere   ( 78 absorbed, 79 reflected)

184 = Space --> Surface      (161 absorbed, 23 reflected)

278 = Space <-- Atmosphere   (199 emitted,  79 reflected)

063 = Space <-- Surface      ( 40 emitted,  23 reflected)
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278 = Atmosphere --> Space   (199 emitted,  79 reflected)

333 = Atmosphere --> Surface (333 emitted)

157 = Atmosphere <-- Space   ( 78 absorbed, 79 reflected)

453 = Atmosphere <-- Surface (356 emitted,  97 convected)

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063 = Surface --> Space      ( 40 emitted,  23 reflected)

453 = Surface --> Atmosphere (356 emitted,  97 convected)

184 = Surface <-- Space      (161 absorbed, 23 reflected)

333 = Surface <-- Atmosphere (333 emitted)

[Clairwil]

For a lesson plan for more advanced years, try comparing with other sources, such as:

http://web.me.com/uriarte/Earths_Climate/Downwards.html

and:

).

From: http://www.indiana.edu/~geol105/1425chap4.htm

The total amount of energy that moves through the system is huge. It is on the order of 174 ,000 terawatts (1 terawatt = 10¹² watts [energy per time]; 1 horsepower = 746 watts).  Almost all of this energy comes to us via solar radiation.  The Earth system receives 5000 times more energy from the sun than from the interior of the planet.  Thus, although its manifestations are impressive (mountain ranges, earthquakes, volcanoes), the internal energy that keeps up mantle convection and drives the tectonic plates is only a small fraction of the energy that moves through the system.   To put it into perspective, the total energy production by humans is about 9.6 terawatts at any given time.  Thus, there is plenty of energy in the system.   Even if humans were to extract all their energy needs from the solar input, there would still be plenty of energy left to keep the planet going.

[Clairwil]

For 17-18 year olds, you can throw in a bit of physics about black body radiation:

The most relevant part of that universal what-else is the requirement laid down by thermodynamics that, for a planet at a constant temperature, the amount of energy absorbed as sunlight and the amount emitted back to space in the longer wavelengths of the infra-red must be the same. In the case of the Earth, the amount of sunlight absorbed is 239 watts per square metre. According to the laws of thermodynamics, a simple body emitting energy at that rate should have a temperature of about –18ºC. You do not need a comprehensive set of surface-temperature data to notice that this is not the average temperature at which humanity goes about its business. The discrepancy is due to greenhouse gases in the atmosphere, which absorb and re-emit infra-red radiation, and thus keep the lower atmosphere, and the surface, warm (see the diagram below). The radiation that gets out to the cosmos comes mostly from above the bulk of the greenhouse gases, where the air temperature is indeed around –18ºC.

http://www.economist.com/displaystory.cfm?story_id=15719298