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# The contribution of metabolic heat to climate change.

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Human beings are endothermic organisms that generate metabolic heat. That heat warms up the environment humans live in. The environment humans live in is the biosphere of planet Earth. Planet Earth is the globe that's referred to in the phrase "global warming".

Yes, we might be in a natural warming trend, but heat is cumulative. If there is a natural warming trend then we're adding ~6.5 billion human generated heat sources to something that's already warming up plenty on it's own.

I'm looking for one or more "certified" scientists to either confirm or discredit my statements. All relevant comments, questions, and/or links to related information will also be appreciated.

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It's insignificant when you take into account IR from sun rays.

Most of the world's populations live in the tropics. Their bodies are constantly trying to cool themselves because the air around their bodies is much hotter than the heat their bodies are generating.

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Useless post so I can have a post count of 10 and post a reference link in the following post.

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It's insignificant when you take into account IR from sun rays.

Most of the world's populations live in the tropics. Their bodies are constantly trying to cool themselves because the air around their bodies is much hotter than the heat their bodies are generating.

Thanks freeztar, but I'm not attempting to quantify significance at this time.

Second Law of Thermodynamics:

The second law states that heat energy cannot be transferred from a body at a lower temperature to a body with a higher one without the addition of energy. Thus, warm air outside can transfer its energy to a cold room, but transferring energy out of a cold room to the air outside requires extra energy (as with an air conditioner).

thermodynamics - Definitions from Dictionary.com"]http://dictionary.reference.com/browse/thermodynamics]thermodynamics - Definitions from Dictionary.com

It takes energy for people to keep cool in the tropics. That energy eventually becomes heat. In addition to this I don't think that many human beings live in places that have an average day & night temperature that's above body temperature. Even if they do it I don't believe it will excuse them from the second law.

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Heat is not so much the issue as what happens to the heat as it rises through the atmospher? Can it esape, or is it trapped by greenhouse gases?

As for body heat of humans, don't forget to subtract the body heat of the creatures we have displaced and the ones we continue to drive to extinction.

I would suspect that our industrial heat waste is as much, if not more than simply our body heat.

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Human beings produce no more heat than is contained in the food they consume. For an average human, this is about 2000 kcal/day, or about 100 Watts. The current world population is about 6.5 billion, so the total rate of heat output for all of the human beings on Earth is about 660 GW ($6.6 \times 10^{11} \, \mbox{W}$).

The total energy input of the Sun is $1.74 \times 10^{17} \, \mbox{W}$. It varies by about 0.1% roughly every 11 years. (sources: wikipedia articles “Earth's energy budget” and “Solar variation”).

So the total heat output of all the human beings on Earth is about 0.04% that of the normal 11-year cycle of solar variation. In other words, for human beings to have the same impact on climate as the Sun’s slight 11-year cycle of variation, the population would have to be 2500 times greater, or about 16 trillion.

Based on this, I think “The contribution of [human] metabolic heat to climate change” is negligible.

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As for body heat of humans, don't forget to subtract the body heat of the creatures we have displaced and the ones we continue to drive to extinction.

Not too mention all the cows and chickens we take out of the equation daily. (I know, I know...they're replaced)

I would suspect that our industrial heat waste is as much, if not more than simply our body heat.

Indeed.

@Shapedoctor

If you don't want to quantify significance, then you might find this more to your liking, a quantification of heat:

Human Heat Balance

Using an average from the variables and multiplying by estimated population size, one could figure out the total heat generated by humans worldwide.

But of course, there are other factors to consider...

Could it contribute significantly to global warming? Not imo. We're probaby doing much more harm by exhaling.

It would be interesting to see a comparison with, say, geothermal radiation, though.

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Heat is not so much the issue as what happens to the heat as it rises through the atmospher? Can it esape, or is it trapped by greenhouse gases?

As for body heat of humans, don't forget to subtract the body heat of the creatures we have displaced and the ones we continue to drive to extinction.

I would suspect that our industrial heat waste is as much, if not more than simply our body heat.

I'm already assuming that global warming is taking place and I have a pretty good understanding of the greenhouse effect and the effects of human industry on our environment.

The challenge at hand is to figure out whether or not we contribute to global warming as animals. For simplicity let's assume that any animals we have displaced would have the same total metabolic effect on the environment that we have.

In other words, would a solitary human being living as an animal in the wild contribute to global warming to some degree? Again, I'm not looking to quantify that degree at this point and I don't want people saying it's not significant. Some amount of contribution either exists or doesn't.

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You beat me to it Craig!

But I was hoping that ShapePhD would work it out...

Nonetheless, those are great numbers to illustrate the point.

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It would be interesting to see a comparison with, say, geothermal radiation, though.
From the links in post #6, The Earth’s geothermal output is 23 TW ($2.3 \times 10^{13} \, \mbox{W}$), about 35 times the heat output of all humans.
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In other words, would a solitary human being living as an animal in the wild contribute to global warming to some degree? Again, I'm not looking to quantify that degree at this point and I don't want people saying it's not significant. Some amount of contribution either exists or doesn't.

I'm confused now...Does a butterfly flapping its wings affect weather on the other side of the world?

"Some amount of contribution exists" is correct.

As Craig pointed out quantifiably, the amount of contribution is not significant.

(just teasing you, Shape)

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Not too mention all the cows and chickens we take out of the equation daily. (I know, I know...they're replaced)

Indeed.

@Shapedoctor

If you don't want to quantify significance, then you might find this more to your liking, a quantification of heat:

Human Heat Balance

Using an average from the variables and multiplying by estimated population size, one could figure out the total heat generated by humans worldwide.

But of course, there are other factors to consider...

Could it contribute significantly to global warming? Not imo. We're probaby doing much more harm by exhaling.

It would be interesting to see a comparison with, say, geothermal radiation, though.

Thanks for the link. It sounds interesting and I'll be checking it out.

I think we're probably doing more harm with our CO2 as well, but the debates I see about global warming in forum arguments tend to fly all over the place. The skeptics tend to pollute the issue with endless links and distractions. I'm attempting to make an ultra-simplified proof that we do in fact contribute to the heating of our environment.

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Human beings produce no more heat than is contained in the food they consume. For an average human, this is about 2000 kcal/day, or about 100 Watts. The current world population is about 6.5 billion, so the total rate of heat output for all of the human beings on Earth is about 660 GW ($6.6 \times 10^{11} \, \mbox{W}$).

The total energy input of the Sun is $1.74 \times 10^{17} \, \mbox{W}$. It varies by about 0.1% roughly every 11 years. (sources: wikipedia articles “Earth's energy budget” and “Solar variation”).

So the total heat output of all the human beings on Earth is about 0.04% that of the normal 11-year cycle of solar variation. In other words, for human beings to have the same impact on climate as the Sun’s slight 11-year cycle of variation, the population would have to be 2500 times greater, or about 16 trillion.

Based on this, I think “The contribution of [human] metabolic heat to climate change” is negligible.

Thanks Craig. Sorry I skipped your post, but I often end up reading threads upside down for some reason. This looks interesting and I will definitely reply to it again after I've studied it some more.

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the debates I see about global warming in forum arguments tend to fly all over the place. The skeptics tend to pollute the issue with endless links and distractions.

Have you checked out the threads here? I'm assuming you have, but I don't recall any of your posts there. I hope you're not speaking of the threads here? Occasional distractions are a given, but I find the global warming threads here to be very engaging. It's kind of like Joe Friday, "Just the facts Ma'am". (although it doesn't always pan out that way)

I'm attempting to make an ultra-simplified proof that we do in fact contribute to the heating of our environment.

This is a good idea in theory, but will not hold much clout because more significant sources of heat, or heat 'retention', exist and are much more of a threat (especially considering that lobbying human genocide for global cooling is not going to attract many fans...aye, I would hope zero).

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From the links in post #6, The Earth’s geothermal output is 23 TW ($2.3 \times 10^{13} \, \mbox{W}$), about 35 times the heat output of all humans.

The math in my head is mostly asleep, but this information you're posting looks very useful. I might like to quote you on another forum if it would be ok. I'm not sure what the etiquette is for things like that.

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I'm confused now...Does a butterfly flapping its wings affect weather on the other side of the world?

"Some amount of contribution exists" is correct.

As Craig pointed out quantifiably, the amount of contribution is not significant.

(just teasing you, Shape)

It does in my universe. I don't believe in insignificance.

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Have you checked out the threads here? I'm assuming you have, but I don't recall any of your posts there. I hope you're not speaking of the threads here? Occasional distractions are a given, but I find the global warming threads here to be very engaging. It's kind of like Joe Friday, "Just the facts Ma'am". (although it doesn't always pan out that way)

This is a good idea in theory, but will not hold much clout because more significant sources of heat, or heat 'retention', exist and are much more of a threat (especially considering that lobbying human genocide for global cooling is not going to attract many fans...aye, I would hope zero).

Since I'm actually engaging in some conversation here I'll probably start poking around in some other threads. The forum I frequent the most is big, very fast, and somewhat hostile towards intelligent life forms. It's mostly foul and kind of like a sewer, but every so often I find a treasure in it.

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