Are heat emissions as bad as greenhouse gasses? Most of the technology we use generates excessive heat. Like cars, computers, smartphones, batteries etc... All of these needs to be cooled down in some way. Is all this extra heat adding to rising temperatures? Isn’t pursuing nuclear energy (fission or fusion) bad thing then? Even if it is clean energy. If energy doesn’t come from the sun, wouldn’t that automatically create imbalance in global temperature?
 A: Suppose we burn 1L of gasoline, which releases about 30 MJ of energy and about 2kg of CO2. We would like to estimate how much energy that CO2 will prevent from being radiated out into space before it is reabsorbed in the carbon cycle. Unfortunately this direct comparison is quite hard, so let me propose a different measure.
Instead lets imagine that we've built an enormous magic-glass column to contain our experiment (magic-glass is transparent to all frequencies of light), and just ask if that column is a 1 m^2 cross section how much we've changed the concentration of CO2 vs how much burning has increased the temperature.
Atmospheric pressure is about 10^5 N/m^2 so there is approximately 10^4 kg of air in the column. 0.04% (400ppm) of that is CO2 or about 4kg. So actually we've made a big increase in the amount of CO2 in the column, about a 50% increase.
Meanwhile the heat capacity of the column is about 100 MJ/degree K, so the burn only raised the temperature about 0.3 K. The effect of raising the CO2 concentration by 50% is excepted to be waaay larger, although estimating it requires detailed climate models.
I hope someone who actually studies climate science can tell me if these numbers are reasonable.
