Another math time! 
And again, it is closely related to GW area.
Currently (as of year 2007), human population on earth is 6.6 billion (via wikipedia). I went around to look for how much CO2 is exhaled out per person, and 2 claims were found (both via wikipedia):
claim#1: an average person’s respiration generates approximately 450 liters (roughly 900 grams) of carbon dioxide per day (CO2#Human_physiology)
I use the standard chemistry textbook theory (standard molar volume) to check this claim, 450L for 900 grams of CO2, and it is tallied.
Thus, the amount of CO2 released by human per day is 0.9 kg/day
claim#2: In an average resting adult, the lungs take up about 250ml of oxygen every minute while excreting about 200ml of carbon dioxide. (Respiratory_system)
So, 200 ml per minute and thus 200 ml x 60 X 24 = 288L
Or equivalent to 565.36g/per day = 0.565 kg/day (after divide with standard molar volume constant and times with CO2 molar weight).
Apparently claim#2 has lower CO2 emission compared to claim#1, but I will use both anyway to show the comparison.
So, if there is 6.6 billion people out there and excreting CO2 at the rate of 0.9 or 0.565 kg/day, the total CO2 emission by human alone annually is:
claim#1: CO2 emission = 0.90 X 365 x 6 600 000 000
= 2.168 x 10^9 tonnes/year
claim#2: CO2 emission = 0.565 x 365 x 6 600 000 000
= 1.362 x 10^9 tonnes/year
But human activities, through the fossil fuel burning activities, releases 24.136 x 10^9 tonnes per year (via wikipedia).
So, human breathing process contribute to about 8.99% (claim#1) or 5.65% (claim#2) compared to the fuel burning related CO2.
Conclusion? May be stop breathing does not really help in reducing CO2 emission! 
Math! How much CO2 is released by Dairy Cow? « small-m said,
April 12, 2007 at 4:53 am
[...] compared this value to human being on earth (as of year 2007), human population is breathing about 1362 million tonnes (case#1) or 2618 million tonnes (case#2) CO2 per year. By comparing the [...]
Brian Muller said,
May 15, 2007 at 2:30 am
Your math is off in example number 1 the answer should be 2.168 x 10^12 tonnes/year.
Thats off by 1000 times do your math again.
mich said,
May 15, 2007 at 6:27 am
Hi Brian:
0.90 kg/day x 365 days x 6 600 000 000 = 2.168×10^12 kg or 2.168×10^9 tonnes/year (1 tonne=1000 kg). I skipped the kg conversion to tonnes part. Checked if the number is tallied with yours.
Neil Chapman said,
June 16, 2007 at 12:46 am
By my coarse calculation a typical car generates about as much CO2 as 12 people. That means 6.5 billion people are equivalent to 500 million cars.
micpohling said,
June 16, 2007 at 1:29 am
Hi Neil:
Well, let’s say a typical car emit 200g CO2 per 1 km travelled, and for a car to generate 12 persons CO2:12×0.9 kg = 10.8 kg CO2, that would be equivalent to 54km travelling distance per day. Do you drive your car that much?
Ed C said,
July 16, 2007 at 5:55 pm
Very interesting stuff! Also useful for someone like myself whom is convinced global warming isn’t our fault (well, cars and CO2 anyway). My maths teacher told me that 50% (could’ve misheard it, might be 15%) of CO2 emissions are emitted by the production of concrete. Can anyone back this up? Thanks!
Ed C said,
July 16, 2007 at 6:11 pm
PS: I heard the average human emitted 400kg (0.4 tonnes) of CO2 a year so 0.4[tonnes] x 6600000000 = 2640000000 (tonnes 2.64 x 10^9 tonnes/year I think) > 2.168 x 10^9 tonnes/year. Not sure what total CO2 emissions are and haven’t the time to work it out!
mich said,
July 16, 2007 at 10:59 pm
Well Ed, your average 400kg per year is definitely slightly higher than my daily 0.9kg (less than 1 kg per day x 365 days will definitely less than 400kg/year), so your calculation would yield higher number than mine. As for the concrete production, sorry for not hearing about that before. A quick check at Wikipedia, I guess the CO2 was released by Portland cement component in concrete ” Portland cement, which is made primarily from limestone, certain clay minerals, and gypsum, in a high temperature process that drives off carbon dioxide and chemically combines the primary ingredients into new compounds.”
http://en.wikipedia.org/wiki/Cement
Ed C said,
July 18, 2007 at 4:02 pm
Thanks for the info mich.
I checked again with my maths teacher, and she is convinced it is 51% (CO2 emitted by concrete/cement [?] production). But then again, she is just a bit mad…
I only got the 400kg pa figure from a letter written to the motoring magazine, Top Gear, so I don’t know how valid that is. Thanks again for the very useful article.
Adam said,
August 4, 2007 at 6:04 am
The catch with cement factory emissions, is that in the hardening of the lime (calcium oxide) back into limestone (calcium carbonate), the primary ingredient in concrete to make it harden, the CO2 is put back in, so the net effect is entirely from the burned fossil fuels required to heat the limestone and cook it into lime, and not of the product itself. And that’s with a rediculously efficient process. You want to talk terrible emissions, gas lawnmowers spit out all sorts of terrible crap and are horribly inefficient. Even candles are horribly inefficient as a light source.
Tell your teacher to do HER homework next time she tries to tell you to do yours
Ed C said,
August 4, 2007 at 7:44 am
Thanks Adam, I sure will! I see your point with the concrete hardening process as I recently studied this at school. The quest continues to find that global warming isn’t entirely our fault… (probably a lost cause by now)
kevin said,
August 14, 2007 at 1:09 pm
This s not really a math question, but a thought of why with technology advancing at such a rate, hasnt anybody invented/discovered a method of changing CO2 into base elements carbon and oxygen. Please forgive my ignorance if there is a simple answer to this.
mich said,
August 14, 2007 at 5:25 pm
Well, the problem is breaking a stable molecule like CO2 into base C and O requires energy (be it natural process like photosynthesis or artificial), so it will eventually comes back to original question: where do you get the energy from?
snowy said,
August 19, 2007 at 12:10 am
erh does n’t
6H2O + 6CO2 ———-> C6H12O6+ 6O2
six molecules of water plus six molecules of carbon dioxide produce one molecule of sugar plus six molecules of oxygen
so basically if we breath toward a big enough sunlit plant while we water it – that should sort our our own individual carbon offset !!!! and we get to have some sugar for our latte too
Rahul P said,
October 19, 2007 at 10:15 am
If I were to offset the CO2 by planting trees for my own quota of CO2 , how many and what type of trees are required to plant and keep em alive as long as I am breathing …
Bob Bennett said,
November 2, 2007 at 5:39 pm
How much carbon dioxide is contained in one cubic metre of limestone.
An average quantity would be most helpful to me as I need to kinow how much is given off when burning limestone at 900 degrees C ?
Max said,
November 16, 2007 at 12:26 am
Human breathing process is not contributing to net gain of CO2 because:
“human exhalation of carbon dioxide is part of a closed system. There can be no net addition of carbon dioxide to the atmosphere because the amount of carbon dioxide we exhale can’t be greater than the carbon we put into our bodies by eating plants, or eating animals that eat plants. The plants got the carbon from the atmosphere via photosynthesis.”
http://www.gcrio.org/doctorgc/index.php/drweblog/C53/
And, yes, the solution is planting trees. In my childhood days, the mantra was “5 trees per person and we’re fine”. Have no idea if this was scientifically proven/supported.
mark teeter said,
December 21, 2007 at 4:44 pm
Hello econerds! Does it not occur to anyone that humans are not the only carbon dioxide emitting organisms on earth? Please try calculating CO2 emissions for all life. Eat your pets first, but only make jerky out of them by sun drying.
Adam L said,
April 2, 2008 at 10:38 pm
I think that teacher means 51% of CO2 from manufacturing (metal refining is another big contributor in this category). Cement accounts for more like 5 to 10% of TOTAL CO2 emissions. Even livestock contribute more CO2 emissions than the cement industry. Beef livestock account for 9% of CO2 (but 37% of methane and 65% of NOx, which have greater potential warming effect than CO2).
By the way, the total amount of atmospheric CO2 only rises by about half of the total global emissions each year. The other half gets absorbed by the oceans. Basically, shellfish need it to make the CaCO3 for their shells.
Cahal said,
May 1, 2008 at 10:13 am
The carbon molecule you breathe out has come from a plant, or an animal that ate a plant. While the plant was growing, it took in this carbon molecule from the atmosphere, in the form of CO2. So the whole process is carbon neutral obviously. The same applies for all life on earth, and there is no net effect on global warming.
Apart from when the carbon molecules are formed with hydrogen to make methane (think cows). Since methane is 12? times as effective a greenhouse gas than CO2, a CO2 molecule taken up by the plant ends up as a CH4 molecule in the atmosphere.
Pigeonwolf said,
May 7, 2008 at 9:01 am
By the theory that the carbon we breathe came from a plant (or animal that ate a plant), we could use the same theory that fossil fuels come from fossilised plants or fossilised animals that ate plants and are thus carbon neutral. The theory (whilst being technically true) is obviously flawed, not least in that around the world, forests are being burned to make room for farmland to feed the ever expanding population. We are thereby losing a constant in the equation (trees).
Tyler said,
May 8, 2008 at 11:42 pm
What wikipedia page did you find that on?
SY said,
May 17, 2008 at 1:35 pm
It is true that the whole world is a closed system, with fixed amounts of carbon, oxygen and other elements. The problem is the balance between the forms of these elements. Currently we appear to be producing CO2 (gaseous form) faster that it is being re-absorbed as pants and trees (solid form).
Actually the Human Race is the problem, not only through breathing out CO2, but by consumption too. The world would be in balance with a smaller population. Population growth is the real problem to everything!
Daniel said,
June 15, 2008 at 12:30 pm
Has anyone considered that plant life on earth may be limited by the fact that CO2 is less than 0.04% of the content of air. By contributing extra CO2 we could actually be encouraging plant life to develop as there would be higher concentrations of CO2 for the plant to breathe and thus allow to grow. Even if we clear forests etc, the plants will still find a way to thrive as life always has. Maybe we will see plants grow further inland thus creating more rains (as the oxygen meets hydrogen in the air and creates clouds/rain) on mainlands. To me this is common sense. Can anyone point out otherwise?
William Tell said,
July 3, 2008 at 7:42 pm
Wikipedia, the stated source for much info generating claimed factual science should be held in the highest level of skepticism. Individuals attempting to correct their personal bio’s have reported their attempts repeatedly corrupted to reflect falsehoods. This is an example of the inside agenda of select Wikipedia editors molding topics and content. Although this is not pervasive throughout Wikipedia as yet, it is worth noting for the most polarizing topics of debate. Be sure to use multi-facet cross checking of data to support all of your facts.
Tiburon said,
July 4, 2008 at 11:11 pm
Yes, the positive effects of CO2, especially in light of our growing population’s need for food and shelter (expected to stabilize around 13 Billion or so demographically, as I recall), has been well considered! See: – CO2Science.org.
This will be an especial boon while we go through what’s beginning to look like a repeat of the Dalton Minimum (Little Ice Age/LIA).
shmoopie said,
July 6, 2008 at 5:52 pm
The problem is that you have all fallen for the construct that CO2 is bad and causes global warming.
ALL GASES are greenhouse gases.
Our atmosphere is 79% Nitrogen, 20% Oxygen, 1% everything else. The everything else makes only a small component of how radiant energy is trapped by the atmosphere. And CO2 is only 0.2% of the atmosphere. Now, on the other hand, Methane is MUCH more dense than O2, CO2, or N2. If you accept the great Global Warming Religion, we should all be burning as much natural gas as possible (currently seeping out of the ocean floor at an alarming rate) and converting it to CO2 and H2O.
BTW, the “Science” behind Global Warming is being proven fraudulent.
The 1990s and 2000s were NOT the hottest period in modern history, the 1930s were. The methodology of putting an ever increasing number of weather stations in urban an suburban settings (heat sinks- steel, concrete, and asphalt), in some cases next to air conditioning exhaust on rooftops, and comparing them against different measuring devices with less accuracy and, trying to statistically compare to within a fraction of a gradient (not possible on the older instruments) is the very definition of UnScientific.
The last 2 years have been frigid, just as the last 3 Atlantic Hurricane Seasons after Algore’s movie have been unusually quiet.
Oh, and the Earth is NOT a closed System. Heat from the Earth comes from The Sun. The Sun is not a constant. Global warming Religion makes no room for varying output from The Sun in it’s models. Strange, huh.
Semaj said,
July 23, 2008 at 6:49 pm
Does anyone know how much fossil fuel there is on the planet, and how much co2 would be released if it was all burnt?
Joey said,
August 1, 2008 at 1:25 pm
I came to this site late. Where did we get the idea that C02 is dangerous or that the world is in a period of man-made global warming caused by a C02 canopy around the earth which is creating a “greenhouse’ in which warm greenhouse gases from earth are trapped thereby raising earth’s temperatures ala man-made global warming???
Whew.
Talk about run-on sentences. But you get the point. I think its all a lot of (for lack of a better word) crap. There is no man made global warming. Co2 is not dangerous at all. In fact it is an intergral part of our life system. Al Gore is nuts.
So how come so many scientists follow the lead of this silly pied piper? I guess for the same reason so many experts once thought the Sun revolved around the Earth or that the Earth was flat. Swimming with the current is always easier than going against it.
Look. Global warming is nonsense. Any one of the people who visit a site like this is capable of understanding this fact if they want to. So let’s review:
A canopy of C02 now surrounds the earth creating a sealed-in ‘greenhouse’. Below the canopy, earth’s warm greenhouse gases can not escape the earth so they reamain raising the Earth’s temperature. Each day taht the canopy stays in place, the Earth must get warmer. Each day, warmer than the day before. Unless we fine an escape for the trapped heat or turn off the heater (the greenhouse gases), we are doomed to ever-increasing temperatures and eventually DEATH FROM WARMING.
(This is terribly different from what these same guys said in 1975 when they used all the same words except one: then they used the word COOLING, now they use the word WARMING.
Both conclusion came from analysis of the same data.
BUT – and it’s a big but –
Last week (July 2008), the NOAA released this statement:
“Five of the last twelve years were above the 180-year mean. This means they were the five warmest years on record.” (That’s a paraphrase but that’s the gist of it.)
So, this is what the last 12 year’s temperatures looked like, beginning in 1995: cooler/cooler/cooler/warmer/cooler/
cooler/cooler/cooler/cooler/warmer/cooler/warmer (2006).
Now I ask you, what kind of greenhouse is that? Is there a leak? Did someone turn off the greenhouse gases. Are those hot gases escaping out the hole in the ozone layer???
Can’t you see greenhouses don’t work like that? If you have a sealed in area with a constant source of heat and no way for the heat to escape, the temperature inside that greenhouse must be as warm or warmer than the day before. It can NEVER be cooler than the day before. And you can’t have a cooler season following a warmer season. It’s downright silly.
If man-made global warming were real as Gore (the winner of the Nobel Prize – god help us all), but if Gore was right,
all four seasons would be merging into one. The summers would be hotter, the springs would be hotter, the falls would be hotter and the winters would be hotter. And since we have had the Industrial Age for over 180 years, by now our seasons would be gone.
No, there is no man-made global warming. That’s just nonsense. If some seasons are warmer and some are cooler as shown by the NOAA statement, that’s called WEATHER. And the things that account for that are (1) Solar Activity and (2) water vapor (or droplets) in the air. And that doesn’t come from us, that comes from nature.
So what’s this all about? Blaming C02 means blaming American Industry. This leads to taxes on industry which leads to less drilling in America which leads to our corporations going out of business and our economy failing. Which leads to the re-distribution of our wealth and the destruction of capitalism and the introduction of marxist/socialism to the United States.
Far feteched? Why? The C02 scare (remember the ozone hole blamed on C02?? Remember the global cooling scare blamed on C02? Now you have the same scare tactics with global warming.) The goal is to destroy America’s wealth.
Today, because of this C02 nonsense, we don’t drill for oil. But we still use it. We HAVE to use it, there is no real alternative today. So we buy it and send $700,000,000,000 dollars out of America to foreign countries. They are doing very well, their econmomies are booming, and ours? Ours is collapsing. And this is all an accident? This is all because scientists can’t figure out we do not live in a greenhouse? When its own government says each year, temperatures alternate between warmer and cooler? They can’t stand up and say Mr. Gore, you are an idiot?
Can’t or won’t? If it’s won’t, why not? Could it be fear of reprisals?
There is no man made global warming and for now I am ont convinced there is no ongoing warming at all. In fact, here is a prediction: if solar activity doesn’t pick up soon (in the next 3 years) we are in for a prolonged period of GLOBAL COOLING.
Joey
You may email thoughtful responses to me at :
Chonors686@Aol.com.
Identify the email. I delete a lot.
Thank you.
Jeff Glassman said,
August 3, 2008 at 3:55 pm
Your calculations on human CO2 respiration are OK, but I couldn’t confirm your number of 24.136 X 10^9 tonnes per year at your linked Wikipedia site. Instead, at that site the first figure has two graphs, and the lower graph has a blue line for the total fossil fuel burning rate. At year 2000, the end of the graph, the rate is 6.6 X 10^12 kg Carbon/year. That is 6.6 X 10^9 tonnes Carbon/year, roughly one fourth your value.
So instead of 8.99% under claim #1 as you state, the number is 33%.
This number is significant, especially compared to the total flux from the red line on that same Wikipedia chart. It’s about 3.9 X 10^12 kg Carbon/year at year 2000, or 3.9 X 10^9 tonnes C/yr. Now your calculation is 2.168/3.9 = 56% of the total (net actually) atmospheric CO2 rate.
michelle said,
August 3, 2008 at 5:29 pm
Jeff,
Please bear in mind that the weight of CO2 is not the same as Carbon itself.
C + O2 -> CO2 [12 + 2*16 -> 44g]. By using this equation, you will get 6.6×10^12 kg C/year is equal to 24.136 x 10^12 kg CO2.
Jeff Glassman said,
August 3, 2008 at 7:35 pm
Michelle,
Your are correct, and 8.99% it is.
Your reference to “24.136 tonnes per year (via Wikipedia)” might be better written as “24.136 tonnes CO2 per year” especially because that number does not appear in the reference, and because you made two unit conversions, the explicit change from kg to tonne, but a silent one from C to CO2, to apply the reference. The IPCC claims to have uniformly used the mass of C in CO2 to represent the mass of CO2. In your citation, Wikipedia refers to “9.1PgC y^-1 of total anthropogenic emissions”, a carbon reference standing for CO2 mass rate.
Still, my error.
J Clarkson said,
November 5, 2008 at 1:03 pm
CO2 absorbs all of the IR after just a few metres. Only when it gets into the higher atmosphere from aircraft does it cause some mild warming, which will taken a few thousand years to raise the temp by 6 degrees. This won’t happen because the Earth has a thermostat: its called precipitation. This is not factored into IPCC computer sims. Also by the time CO2 really takes effect the Earth will be in the Taurid streams cluster. By the year 3000 these will be smashing into the atmosphere, polluting us with hydrogen cyanide (the cause of the Black Death) and if large enough, some may even cool the global temperature down by putting dust into the higher atmosphere.
Is "global warming" BS? - Page 3 - 8th Generation Honda Civic Forum said,
December 16, 2008 at 8:25 am
[...] Originally Posted by CanyonDriver 95% of CO2 emissions are from natural sources, so based on this claim if CO2 is the cause of the rising temperatures then we have no control over it. i guess we can stop breathing, since exhaling emits CO2 Math! How much CO2 is emitted by human on earth annually? small-m [...]
Chris W. said,
December 20, 2008 at 6:30 pm
Numbers released by the U.S. Department of Energy:
(Hopefully it shows up correct)
Role of Atmospheric Greenhouse Gases
(man-made and natural) as a % of Relative
Contribution to the “Greenhouse Effect”
__________% of All Greenhouse Gases__% Natural__% Man-made
Water vapor -_________95.000%____94.999%___0.001%
Carbon Dioxide (CO2) -__3.618%___3.502%___0.17%
Methane (CH4)_________0.360%_____0.294%___0.66%
Nitrous Oxide (N2O)_____0.950%____0.903%___0.047%
Misc. gases ( CFC’s, etc.)_0.072%____0.025%___0.047%
Total________________100.00%_______99.72%____0.28%
Total human contribution in greenhouse gases – .28%! And .117% just in CO2! An insignificant number!
http://www.geocraft.com/WVFossils/greenhouse_data.html
Tom Teate said,
April 22, 2009 at 6:15 pm
Global warming–global cooling–there’s enough math and science out
there to prove that “global warming” does not occur by the hand of man;
When a volcano explodes its natural gases into the upper atmosphere,
nature deals with it.. more gases than man can produce in 500 years of
manufacturing.. Yet we sit around and let Al Gore collect a “mammy” for
promoting the global warming hoax on the population of the world..
–C02–a natural and occuring gas in the creation of the earth and the production of life’s forces– Maybe Obama will take up the idea of
taxing the American people on their C02 emissions..What’s next-the
toilet tax? Aren’t liberals great??
The Arizona Carnivore » More on climate change (or lack thereof) said,
April 24, 2009 at 10:02 pm
[...] Check out this link as well. It’s a good discussion on how much CO2 a human exhales in a day/week/month. Some of it’s pretty dry. Scroll down to comment 29. It’s a good one. http://micpohling.wordpress.com/2007/03/27/math-how-much-co2-is-emitted-by-human-on-earth-annually/ [...]
Adam said,
May 19, 2009 at 11:33 pm
There are so many uncertainties in this topic, I don’t understand how anyone can claim that burning fossil fuels will destroy the planet. The whole “greenhouse gas” idea is still just a theory, and it is in no way even close to being proven to be a reality. Lets say it is a reality, and CO2 does actually trap heat from the sun, how can we consider this to be a bad thing? The earth has experienced much higher temperatures in the past, and life has thrived during those times. It was even much warmer than this when human civilization began. What if the energy from the sun becomes reduced in the near future? We will be wishing we could trap all of the heat that we could.
Everyone is crying about the ice caps melting, but everyone forgets that they have been melting since thousands of years before fossil fuels were ever used. Polar animals will either adapt or go extinct, which is a process called evolution, which has been going on for billions of years on Earth. Then again, this global warming is supposed to put us in a new ice-age right? So the polar bears and Eskimos outta be thinking us when that happens.
I have a little theory of my own: I think these scientists and research organizations have bills to pay. And the only way they can make money is from government grants. To get a grant, you have to do some convincing and persuasive writing. The data that is PRODUCED by these organizations serves that purpose. Their claims depend on the urgent fear of cataclysm to convince the government that there research is important and warrant funding. Throwing in suggestions like gas and industry taxes is like icing on the cake for lawmakers.
At least that is my theory. Just like the theory of global warming, I can’t prove it to be real. But I can certainly prove it to be a problem for the world, and our economy if it were in fact real.
And one more thing: Why is something that emits less CO2 considered “green”? Really, think about it. Since there is often a little leaf or tree depicted on a “green” product, I am guessing that the term green comes from plants. GUESS WHAT, PLANTS LOVE CO2. I would consider the top CO2-producing machines to be the “greenest”.
gene nordell said,
May 22, 2009 at 2:48 am
Right on Adam, just google: (Al Gores financial investments). Looks like huge motivation for his willingness to tell all the lies and half truths both in his phoney movie as well as subsequent speeches! And, his buddy the president is pushing hard for the cap and trade taxes which will provide the subsidies that will boost the already held stocks in “Green” energy development.