Hacker News new | ask | show | jobs
by anonporridge 1581 days ago
Yeah. All civilization consumes around 17 TW of energy while the sun is constantly bombarding the Earth with 173,000 TW.

We could rebase all of civilization on geothermal and the extra heat in the atmosphere would be a rounding error to the sun's energy.

2 comments

I don't think "it's a rounding error" is enough analysis here. A couple of meters of sea level rise, a couple of degrees temperature rise; these could be termed rounding errors.
Not degrees, thousandths of a degree, so possibly something like a centimeter if sea level rise.

Considering nuclear and fossil fuels directly release stored energy and solar increase albido this isn’t a 1:1 increase in energy. Further the earth radiates more energy from hot places than cool, still you can approximate it as something like:

Black body radiation is temperature in kelvin to the 4th power. (285 * (170,017^0.25 / 170,000^0.25) - 285) is an increase of ~0.007 C / (whatever our current percentage of energy from fossil fuels, nuclear, or solar).

It's far less than the variance of direct solar irradiation hitting the Earth given varying differences in distance from the sun in the Earth's orbit. https://en.wikipedia.org/wiki/Solar_constant#Solar_irradianc...

It looks like direct solar radiance is actually 173,000 TW plus or minus 6,000 TW.

So if our energy consumption increases by 4% per year (current global average) for ~110 years, we'd need to capture / produce as much energy as the Sun hits us with. Crazy!
That would also mean going from kilowatts per person to megawatts per person, so yeah that's pretty crazy.