Science Forums 2

[CraigD]

Originally Posted by modest

I believe Belovelife's characterization of "holding more of the sun's energy in the atmosphere" is appropriate.

I agree.

Because the Earth’s atmosphere is very large, a small change in its average temperature entails a large change in its total thermal energy. The specific gas constant of dry air is about 287 J/kg/K. Multiplied by the atmosphere’s mass of about , the energy per degree C temperature is about . Though small in astronomical terms, this is pretty huge in human terms: about 20 time the world’s annual electrical energy generated and used, or 1/10th the total petroleum and natural gas reserves. It’s even appreciable in terms of the Earths total energy budget: about the same as the total solar energy received in 2.78 hours. And this is only the energy difference for a single degree C change in average temperature.

On the other hand, it’s not very sensible to compare the thermal energy of the atmosphere to common power sources, because there’s no practical way to use it directly to do work. Exercises such as the above are mostly useful in keeping a sense of scale and perspective.

Sources: Wikipedia articles “gas constant”, “[wiki]earth’s atmosphere[wiki]”, and “orders of magnitude (energy)”.