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by zeristor 748 days ago
Don’t forget about heat death.

More energy being used heats up the as atmosphere, it doesn’t simply just disappear.

5 comments

You might enjoy Sabine Hossenfelder's video exploring this "I recently learned that waste heat will boil the oceans in about 400 years": https://www.youtube.com/watch?v=9vRtA7STvH4

It turns out we can probably solve this by building planetary chimneys 5km tall that move heat to the outer atmosphere.

That is not what "heat death" means.
> More energy being used heats up the as atmosphere

We’re nowhere close to this being a problem. (Our total energy production is dwarfed by the natural flux.)

Since it seems like you've seen data pertaining to this, do you have any good/reputable sources? I've tried asking in various places about what percentage of planetary warming is due to direct heating from energy consumption, vs. greenhouse gas effects vs. natural causes, but usually just get accused of being a climate change denier and told to go educate myself. I'm really just curious about methodology, want to build a better mental model of how it works and how it's studied, and have never seen any discussions/papers talking about direct heating effects, so don't know where to start.
> what percentage of planetary warming is due to direct heating from energy consumption, vs. greenhouse gas effects vs. natural causes

Humans produce 20 TW of power [1]. (15 if we remove solar, wind and hydro.) The Sun delivers, to the Earth, 44,000 TW [2].

So raising the amount of the Sun's energy the earth retains by 454 parts in a million (329 if we remove solar, wind and hydro) adds to the Earth the energy of our entire civilisation. That is why emissions are the problem. Not our direct heat production.

[1] https://en.wikipedia.org/wiki/World_energy_supply_and_consum...

[2] https://www.nasa.gov/wp-content/uploads/2015/03/135642main_b...

More significantly, indirect heating from increased greenhouse gases is about 400 TW.
Link?
Thanks for making me check, I was off a bit. It's actually more like 1400 TW. Must have dropped a digit when I remembered that.

https://link.springer.com/article/10.1007/s00382-023-06775-x

> the total radiative forcing (RF) by human activities of approximately 2.72 W m^−2 (Masson-Delmotte 2021)

(with the radius of the Earth of 6.4e6 meters and surface area = 4 pi r^2).

It’s quite easy - we have numbers for humanity’s electricity and heat production. We also know how much atmosphere and oceans weigh, which we can multiply by specific heat of air and water. From this you can calculate how much we’ve heaten up the atmosphere/oceans - even ignoring the loss of heat to space/ground our impact is neglible.

Here is chatgpt doing the math - https://chatgpt.com/share/e/5d28257f-f51b-40e7-8742-75d75e2d... - it’s roughly correct.

All the energy we ever produced and are likely to produce in the forseeable future has neglible impact on the atmosphere’s temperatures.

(Unlike co2 ofc)

Here is gpt doing estimates - the numbers are similar to the ones I calculated by hand some time ago: https://chatgpt.com/share/e/5d28257f-f51b-40e7-8742-75d75e2d...

Well, yes, kind of. But the Stefan–Boltzmann law has the temperature^4 means the earth should radiate it back into space. No?