Know how the temperature in a closed space will rise once it is full of people? Is it possible that the overall population increase on the planet has had any effect on the overall temperature?
I realize that this is just a thought, and I don’t intend to spark debate over the true causes of climate change or blah blah. Yes I realize that there are many other things which cause heat to be dumped into the atmosphere like cars and factories, and cows pooping and farting, etc.
I just want to know if it’s possible to quantify the effects of human body heat on the planet. Y’know, since there’s a bunch of us…and many more than were around a long time ago.
Maybe we could start with quantifying the total heat output of a person? And see how much that would effect ambient temperature? In a room? In a field? Then extrapolate that to a bunch of people…possibly the population of the Earth?
I have absolutely no idea where to begin getting real numbers for this sort of thing.
It would be absolutely vanishingly trivial. Ballpark figures:
A human produces something like 100 watts worth of heat. Multiplied by 7 billion people, that’s 700 gigawatts worth of heat. Quite a considerable sum taken out of context.
But compared to the power of the sun, that’s nothing. 174 petawatts hit the entire atmosphere, and after various reflection and re-emission, 89 petawatts reaches the earth’s surface. That’s over one million times more energy than is generated by every human body.
Besides, a human is just one small step in converting stored solar energy (as plant matter) back to heat. If it wasn’t us, it’d be some other organism.
My back of the envelope calculation gives a similar figure. To put it in context, it’s a similar amount of energy to that produced by all the nuclear power plants in the world.
As humans have increased, other heat-producing animals have decreased by a similar mass. No net difference. And as lazybratsche said, the heat we produce is really just stored solar energy (in our food) being converted back into the same heat it would have become if it had hit bare ground, instead of growing food. Again, no net difference.
You don’t even need to do a BOTE calculation of human heat production. It’s simply the inevitable result of the operation of the laws of thermodynamics. Energy out must equal energy in, and solar energy is the only significant input.
On a related note, it’s not the actual heat released from burning fossil fuels that is raising the temperature of the planet by any significant amount. It’s the release of carbon dioxide into the atmosphere which acts like a heat magnet, “attracting” much more of the sun’s energy to stay.
