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by devrandomguy 3334 days ago
I'm probably no more knowledgeable than you in this area, but I have a free morning, and this is interesting. My hypothesis, is that the heat that we produce or release to generate usable energy, is an insignificant factor in global warming, compared to the solar heat that we trap with greenhouse gases. Let's find some quick simple stats and do some arithmetic, to figure out how much we are directly heating the surface of the Earth.

According to Wikipedia, the global energy production for 2012 was about 5.616e+20 joules, or 156 petawatt-hours. The Earth has about 1.386e+21 liters of water on it, and I will assume that that water represents the bulk of the relevant thermal mass, when considering weather patterns and sea level.

Now, let's estimate the heating caused by that energy. According to www.bickfordscience.com/03-05_State_Changes/PDF/Specific_Heat.pdf, 4,184 Joules of energy applied to 1 KG of water will raise its temperature by 1 degree Celsius, and this scales linearly with mass. Assuming that Earth-water averages out a density of 1 KG per liter, our 5.616e+20 joules, applied over a year to our 1.386e+21 liter water mass, would heat that water by 1.036e-38 degrees Celcius.

It has been a while since I've done a dimensional analysis, and the scale here are so extreme that I can't tell if my result is sensible. However, if my assumptions are reasonable and my math is correct, and the processes that I have chosen to ignore are insignificant (i.e. radiation into space over one year), then all of the heat that we release in the generation of the global energy supply, has a negligible impact on the temperature of the planet.

2 comments

You multiplied instead of dividing somewhere, the result should be : dT = 5.616e+20 / 1.386e+21 / 4,184 = 9.684e-5, or about 1 ten thousandth of a Kelvin. So still insignificant.
Thanks for doing the math!