I think you overestimate how much energy humans use. We are just very inefficient.
Also, said "dynamo" has been running for a few billion years. We've no concept of how long that is. No mental model. Im sure the the planet will be just fine.
What exactly do you mean by "fine", that you're so sure of?
I hear the phrase a lot, "the planet will be fine". Sure it'll continue to be a ball of matter that orbits the sun a few billion more times, so in that regard it'll do pretty fine as a planet. That's not what people are concerned about when they say they're worried about Earth though.
Internal heat generation is estimated by Davies and Davies (2010) to be roughly 47 Terawatt. With a surface area of 5.1 × 10 m^2, this translates to roughly 0.1 W/m^2.
CL4P-TP comment:
"The earth produces 20TW[1] of thermal energy from radioactive decay in the mantle. This is the amount of warmth that the earth generates, so it should give us a ballpark idea of how much heat we would need to remove from the earth in order to make an impact on the earth's internal temperature. To summarize the heating situation under earth's crust, the existing heat comes from two sources in ~equal parts: radioactive decay, and leftover heat from the earth's creation[1]. Lots of heat hits the earth from the sun but gets radiated back out; It doesn't really have anything to do with internal temperatures[1]."
"As far as I can tell from that wikki page: Current heat in the earth: ~50% radiation, ~50% leftover Internal heat budget: Geothermal Power Consumption + 47TW transferred from the mantle to the crust and beyond[1] - 20TW generated from radiation = Core cooling rate Core cooling rate without geothermal: 0 + 47TW - 20TW = 27TW
The world consumed 22,000 TWh in 2017[2]. That means an average power consumption of 2.5TW.
If all of that was geothermal, we'd be increasing the cooling rate of the earth's core by about 10%."
Also, said "dynamo" has been running for a few billion years. We've no concept of how long that is. No mental model. Im sure the the planet will be just fine.