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Comment by hn_version_0023 | Hacker News Reader

Here's a thing I've wondered, and it's a genuine question. I'm not terribly well educated so please bear with me if every bit of this is wrong... and correct my understanding!

If electricity produces heat through resistance and the earth loses heat to space, if the rate of heat produced by electricity is more than the rate we lose heat to space, won't that warm the earth over time?

If that's the case, wouldn't it then be wise to shut down all electricity production, world-wide?

Please note I'm not advocating this as a "solution" because obviously there are a huge number of problems with throwing humanity back into the stone age.

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This is in theory an issue but it's a much, much smaller one: the extra heat trapped by the CO2 over time emitted from generating electricity is much greater than the heat actually generated from that electricity: the current rate of heating of the earth corresponds to about 100 times worldwide energy production

And this heating would continue even if we produced no more electricity. Stopping fossil fuels is about stopping the rate of increase of heating, not stopping the heating itself (though there is an equilibrium as increasing temperature will eventually cause more heat loss to balance out the heat gain. This will still take a century or so to settle though). it's effectively a low interest but very long debt: continuing to generate electricity with fossil fuels is essentially piling on more warming over a long enough time period.

Also as mentioned in other commends renewable sources like wind and hydro don't actually contribute to heating anyway. Solar does (because panels generally will absorb more radiation than most surfaces on the earth), but only by a fraction of the electricity generated.

If you get electricity from the sun (or the wind, which is essentially sun power), then you are heating the earth no more than it would be heated by the sunlight anyway. You're just intercepting the sunlight power and using it to do something useful, instead of letting it heat up the ground, or letting the wind heat up the air through friction. Similarly with hydroelectric power.

That doesn't apply to fossil fuels or nuclear power, though.

But really, the biggest factor by far is how easy it is for long-wave radiation to escape the earth. One thing that isn't intuitive is that every particle of heat radiation that escapes the earth is likely to have "tried" lots of times before, but been reflected back by greenhouse gases (or has bounced around in the atmosphere a lot, being absorbed and re-emitted by CO2 or methane or H20). Basically, only a tiny fraction of the heat radiated from earth actually makes it to space instead of being reflected back. So changing that balance is really what causes the climate to warm, not generating more heat on earth.

solar is a little funny here: solar panels are generally somewhat darker than most other surfaces, so they will generally increase the heat adsorbed by the earth. But this effect is significantly smaller than the effect of releasing CO2 to generate the same amount of electricity.

Thank you!

Yes, which is why burning fossil fuels is bad, we're releasing energy that didn't radiate into space during a time where the environment was already much hotter... and even at an extreme point coating the earth in solar panels would affect our albedo enough to increase the temperature, regardless if we use the energy they create.

Heat is actually the limiting factor for our growth on this planet. We can grow food off planet, we can't really increase our heat radiation rate.

Every type of energy/work generates heat. That's entropy.

What you're describing is a runaway greenhouse effect, which depends on the composition of the atmosphere. Venus hit one without electric cars: https://en.wikipedia.org/wiki/Runaway_greenhouse_effect#Venu...

> A runaway greenhouse effect involving carbon dioxide and water vapor likely occurred on Venus.

Carbon dioxide is also responsible for global warming on Earth, so putting more of it into the atmosphere with fossil fuels would be the thing to stop/mitigate.

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