The human body temperature is about 37 °C (99 °F), so as the population increases does this cause the Earth's temperature to rise?
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Does human body temperature impact climate change? Directly? It's not even a blip. The Earth's population is 7.6 billion. With each person radiating about 80 watts (basal metabolism), that's about 600 gigawatts, or 760 gigawatts using a round figure of 100 watts. That sounds like a lot, but it's only a tiny fraction of the 18 terawatts consumed by humanity, which in turn is a tiny fraction of the 174 petawatts the Earth receives from the Sun.
Indirectly, yes. A growing population and the desire for greater wealth by a growing population (third world nations and developing nations want to move themselves out of those categories) are key drivers of climate change.
answered Nov 15, 2017 at 12:06
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5$\begingroup$ Metabolic heat is still less relevant than your calculation would make it seem, since if the food wasn't metabolized by humans, it would be by other critters, from elephants down to microbes. $\endgroup$– jamesqfNov 15, 2017 at 19:44
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1$\begingroup$ @jamesqf - This is obviously an upper bound on the direct effect. 760 gigawatts is a tiny number in terms of the Earth's energy budget, orders of magnitude less than the uncertainties in the incoming radiation from the Sun or the outgoing thermal infrared radiation from the Earth. $\endgroup$ Nov 15, 2017 at 20:12
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1$\begingroup$ @jamesqf For stuff growing and decaying or being consumed anyway: yes. But humans tend to burn old stuff which probably would not have been burnt with less humans on board (coal and oil) in order to grow food. So again, indirectly by its sources, this food is "added" to the calculation. $\endgroup$– AlfeNov 16, 2017 at 10:15
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1$\begingroup$ Actually, developed (so-called) nations are the key driver of climate change, both historically and presently, don't palm it off to growing populations in poor countries where their climate footprint is 1/100th of a rich nation person. And don't forget most of Chinese emissions are created manufacturing stuff/consumables for rich nations, so much of their emissions are virtual developed world emissions. $\endgroup$ Nov 16, 2017 at 17:41
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2$\begingroup$ @Alfe: But burning stuff is not part of human metabolism, it's something entirely different. In the absence of humans, things could still burn due to e.g. forest fires, and that "old stuff" could be set alight by say having volcanos erupt underneath coal beds, as is believe happened during the Permian-Triassic extinction. $\endgroup$– jamesqfNov 16, 2017 at 20:53
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All the new energy added to the earth’s environment comes from outside our planet. The sun is the biggest contributor, then other factors like meteors, radiation from other energy sources in our galaxy, etc. All of the sun’s energy hitting the earth either reflects back out into space or is temporarily absorbed by other masses (water, rocks, air, plants, animals) as heat and then radiated back out. Most of the heat eventually radiates back out into space, but some gets reflected back down to earth by the CO2 and other substances in our atmosphere. More CO2 = more heat energy being reflected back down to earth.
When humans and other animals and bacteria consume plant and animal matter, we are consuming the energy from the sun that was used to grow the plants at the bottom of the food chain. Then our bodies burn the stored chemical energy and turn it into kinetic energy and release it into the atmosphere as radiant heat energy. If a smaller human population grew less food then less of the sun’s energy would be temporarily absorbed by those crops and ultimately released back into the atmosphere as heat. More humans growing and consuming more food would cycle more energy through that system, but ultimately there will be equilibrium between the amount of energy consumed by plants and then released back into the atmosphere by the organisms who consume those plants regardless of population size.
So NO, human body temperature itself has no direct lasting impact on the earth’s temperature.
Millions of years worth of our sun’s energy that was temporarily stored by plants in prehistoric times got locked up longer term in oil deposits underground. Humans have been drilling and pumping that oil out of the ground and burning it to make our lives easier/better, but in the process we are releasing millions of years worth of stored energy into the atmosphere in a relatively short amount of time. Much of that released energy radiates out into space, but some of it gets reflected back down to earth by the increasing CO2 levels in our atmosphere. And human’s burning of fossil fuels is the biggest contributor to adding new CO2 to our atmosphere.
Atomic energy powerplants release energy as heat into the atmosphere that would eventually be released into the atmosphere on its own by the radioactive elements themselves even if humans weren’t manipulating them, but at an accelerated rate.
Storing and then using renewable energy such as solar and wind (wind energy originates as the sun’s solar energy moves air around our atmosphere, plus some kinetic energy from the rotation of the earth) are net neutral to our planet.
The energy stored in and released from the earth’s core is another factor that we’ll save for another discussion. In the meantime, let’s all accept that our planet is warming as a result of humans releasing prehistoric energy into the atmosphere at a relatively rapid rate compared to how long it took for that energy to accumulate. (Mic drop)
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1$\begingroup$ "All new energy added to the Earth.... comes from outside the planet" is not accurate. There is significant heating from geologic radioactive decay $\endgroup$– WoodyNov 4, 2021 at 15:23
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Human metabolic heat doesn't add energy that was not already there.
The metabolic heat human bodies produce comes from energy supplied by the food we eat. The energy in that food came from solar energy converted to carbohydrates and proteins by photosynthesis and plant metabolism, either directly (as plant based food) or indirectly (as food for animal products and meat) - it doesn't add energy that was not already present in the climate system.
But the fossil fuel burning that contributed to cultivation, transport, storage and cooking do add energy not already present - from the heat of combustion of energy in long term carbon sinks added directly and an estimated 100x that heat added to the climate system from enhanced greenhouse effect indirectly from the CO2 released.
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1$\begingroup$ The human body may divert some energy that would've been destined for those carbon sinks and instead release it to the atmosphere by eating said plants though :) Though I'm convinced it's not a big factor directly, but again is more dictated by producing a greenhouse gas, methane.. $\endgroup$ Nov 4, 2021 at 4:07
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If I'm understanding your question correctly, you're not asking if human activity impacts the climate. Demonstrably it does, through burning fossil fuels to satisfy energy demand, etc. You're just wondering if humans, only by being warm, have any impact.
Well, an activity-less human is a warm bag of mostly water.
If you put a warm bag somewhere, it will cool down and there will be no long-term impact to the climate. At best you'll affect the weather that day. Then there will cease to be warm bags.
The devil is in the details of what sustains the ongoing presence of warm bags. If you're making warm bags by burning fossil fuels, clearly that's a problem. If you're focusing light and warming them with solar energy, that may be less of a problem. If you're keeping them warm by metabolizing plants, it will depend greatly on the particular agricultural practices used.
Unfortunately, I don't think your question can have an answer. Human activity is inseparable from sustained human existence on Earth.
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As others have pointed out the impact of our own bodies producing heat can be neglected.
That said the fact that we are only comfortable at certain temperatures and try to chance our body environment(via heating or cooling) to match does produce a lot of CO2 which impacts the climate much more strongly.
Similarly the energy we use to heat our body comes from our food which we often produce using fossil fuels which does impact the climate.
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It's more the lack of human body temperature (or rather heat, as the temperature is rather constant while alive) that impacts climate change. The most efficient way of keeping a human body warm in cold weather is directly insulating it and heating with internal combustion. Homeless people tend to do that, and their carbon footprint is exemplary. That's what you are talking about with regard to "human body temperature" affecting climate.
The most energy-conscious "proper" citizen, however, keeps a house heated rather than himself. The surface area of a house is large: insulating it is quite a larger task than insulating a single human (and requires a lot of material that needs to be produced, too). You'll need a whole lot more fuel for that even though you don't heat it to 37°C proper.
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No. Humans obtain energy by the consumption of food, namely carbohydrates (grains) For a typical human body, these energy losses are mostly thermal, in form of body heat. Depending on the activity and the environment, the body dissipates approximately 290 and 3800 kilojoule of thermal energy per hour, translating to a power of 80-1050 Watts (Average 40 kilojoules per person per day). With 7.8 billion people 380 Terajoules. By comparison;An average hurricane stores thermal energy of over 50 Quintillion JOULES! 13,000x more energy
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No they do not , just like 1 icecube won't freeze an ocean that's what all the human population is to this planet.
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Well... The atmosphere is very sensitive to minute changes... The density and aromatic pressure shift if when a butterfly flaps its wings... Ok just saying there is an effect... But the easiest way to measure the difference would be to ask the question... Wood human heat keep us warm if tge sun went out... And that answer is obvious... So no, climate change isnt effected much by human heat...
Besides heat.we are also machines that turn o2 into c02... So that can also be taken into consideration regarding hownare bodies affect climate change... Though again this measure almost nil...
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