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Ken Fabian

Is CO2 humankind's largest single waste product/waste stream?

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If wastewater - usually considered the biggest single human waste product by weight - is waste plus water but we only count the waste, and exhaust gases are air and CO2 but we only count the CO2...  would that mean it is actually Carbon Dioxide that is the largest single human waste product? By weight? By volume I suspect it could be CO2 anyway - and more confidently suspect exhaust gases containing CO2 would be more by volume than wastewater.

It has struck me before just how much CO2 we actually make, mostly oblivious - a more average Australian than me makes 8,000 cubic metres/280,000 cubic feet of CO2 per year. 180 times my own body weight of CO2 per year, 1,800 times my weight per decade, enough I suspect, to make column of pure CO2 with my body's cross section that reaches halfway to the ISS each year. This is going on largely unnoticed in open sight, through an abundance of exhaust pipes and smokestacks, but it looks to me like CO2 is our single most abundant waste product.

Edited by Ken Fabian

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Well we certainly breathe out a lot of hot air as CO2

None more so thanFleet Street and  our Houses of Parliament.

Hopefully you can distinguish between 'most damaging' and 'greatest quantity'.

Edited by studiot

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Human is making CO2 directly and indirectly. Directly by breathing (it's easy to estimate exhausted gas). Indirectly by e.g. burning fossil fuels (coal, oil & gas), by professional modern food production of meat (especially), and plants (e.g. decomposition of unwanted inedible parts of vegetables and fruits, produced by farms). Mass production of cement for housing. And other chemical industry sources.

 

Edited by Sensei

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To blindly go where no man can live - Earth Trek 

I doubt it'll take off...

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It seems its not important because our breathing is part of the global carbon cycle, so there is a negligible net change. The real problem is unlocking sequestered carbon gases in the form of fossil fuels which adds to the global concentration.

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These are 'back of envelope' type estimates, not definitive. I may have been thinking of daily rather than annual wastewater volumes, so wastewater probably does make up the largest volume of human waste - I'll have to go back and look for the right numbers, but my point is, it is still mostly water. Actual waste content is harder to pin numbers to - 500 litres of urine per person per year. Less than 200kg of faeces. Solid waste for Australians, about 1,500kg. Other waste? There will be some, but it still looks like about 7 times more waste CO2 than all other waste combined.

Exhaled CO2 is about 1 kilogram per day or 365kg per person per year, ie 1/40th of an Australian's emissions is from breathing - and as long as we don't count the associated emissions from agricultural production and supply chains exhaled CO2 all came from atmospheric CO2 converted by plants into food to give (approximately) a zero contribution to raised CO2 emissions. The associated emissions from food production don't round out to anywhere near zero though.

I don't think I've ever heard CO2 spoken of as our largest single waste product, but unless someone can show my estimates are way off it looks like it is.

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I tried to find better sources for assessments of how much waste we make - again I have done this from an Australian perspective, but expect the overall conclusion won't be much different in other developed nations.

Looking at Australian National Waste Report 2016 (the most recent I could find) I didn't find wastewater per se or CO2. It does appear to include 'biosolids' from wastewater treatment - which would be less than if they counted the actual urine, faeces and other materials fed into that wastewater, both because the initial water content of them is not counted and a lot of the organic materials are broken down. Some of that material will be released as Methane and CO2 along the way. The report does take account of methane that is collected and burned (but not that which isn't) as fuel and mentions that it becomes CO2, to be added to Australia's emissions inventory, which, like methane emissions, is not part of the report; it's there as a form of waste treatment - "energy recovery" - alongside recycling or disposal (landfill). A lot more construction waste (726 kg of masonry) than I expected - and had thought was counted as municipal waste but wasn't - and a lot of fly ash from coal burning (760kg) which, given the CO2 emissions, didn't surprise me. I used 15 metric tons of CO2 per capita but it is actually over 17 tons

The total waste for an average Australian before recycling, energy recovery or disposal (up to 2014-15) is given as 2705 kg per capita - which makes my previous estimate of CO2 being 7 times more than all other waste combined an overestimate; seems like it is only 6 times more. But that doesn't leave me feeling any better about it.

 

Edited by Ken Fabian

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I am not sure how it relates to e.g. nitrogen emission, but I would not be surprised. CO2 is associated and at the end of many processes, so it is not surprising that we emit loads of it.

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On 07/09/2018 at 11:17 AM, CharonY said:

I am not sure how it relates to e.g. nitrogen emission, but I would not be surprised. CO2 is associated and at the end of many processes, so it is not surprising that we emit loads of it.

Nitrogen - N2 - would be the biggest component of combustion exhaust gases but passes through mostly unaffected. Some NO(x) is produced but only a small portion of N2 that passes through is effected.

I was surprised that CO2 exceeds other waste by such a large margin but I suppose I should not be surprised that the quantity of waste CO2 is so great - nothing about this is secret; more like it has been going unnoticed and unremarked whilst in plain sight.

Edited by Ken Fabian

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6 minutes ago, Ken Fabian said:

Nitrogen - N2 - would be the biggest component of combustion exhaust gases but passes through mostly unaffected. Some NO(x) is produced but only a small portion of N2 that passes through is effected.

I was also thinking in terms of human influence on the nitrogen cycle, i.e. production and release of nitrates etc. But I would guess that overall it would still be far lower, considering that those processes are also again coupled to further CO2 release (directly or indirectly). If you are talking about emission and impact CO2 seems also to be on the upper end of that scale. After all, we are looking at drastic effects on the climate.

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Even after the mass deforestation and population explosion, I think our environment is still equipped to handle the carbon dioxide that we exhale. It is the carbon dioxide from the burning of fossil fuels and industrial waste that is posing a huge threat to our environment. Looking at the slow rate at which climate change awareness is spreading, I feel it would be too late to save the earth as we know it now. 

Edited by lucy brighton

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On 18/09/2018 at 5:04 PM, lucy brighton said:

Even after the mass deforestation and population explosion, I think our environment is still equipped to handle the carbon dioxide that we exhale. It is the carbon dioxide from the burning of fossil fuels and industrial waste that is posing a huge threat to our environment. Looking at the slow rate at which climate change awareness is spreading, I feel it would be too late to save the earth as we know it now. 

Estimates of how much CO2 humans exhale vary and I have not had much success finding accessible published scientific papers for this. From a media article that got it's numbers from Jay Gulledge of the Pew Center on Climate Change - 2.3 pounds per person per day or 840 pounds per year. In kilograms (which I am more accustomed to) about 280 kg per person per year. I've seen other figures around the 400-500 kg per person per year.

The food that the carbon came from would have directly or indirectly drawn that from atmospheric CO2 via plant photosynthesis - and as such should not effect atmospheric CO2 concentrations. However, the contributions of fossil fuels to the growing, processing and distribution of that food can and will contribute to changes to atmospheric CO2.

I agree that the world as we know it will be irreversibly changed by global warming - as well as other human activities. The politics around this issue dismays me - but that is for another thread. I'm not entirely without hope that the politics will shift and that we can regain some degree of climate stability to leave as a legacy - a changed but more steady climate state rather than still rapidly changing. Some effects will continue no matter what we do - a lot of sea level rise over the next few centuries seems hard to avoid now.

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On 9/5/2018 at 8:20 AM, Ken Fabian said:

If wastewater - usually considered the biggest single human waste product by weight - is waste plus water but we only count the waste, and exhaust gases are air and CO2 but we only count the CO2...  would that mean it is actually Carbon Dioxide that is the largest single human waste product? By weight? By volume I suspect it could be CO2 anyway - and more confidently suspect exhaust gases containing CO2 would be more by volume than wastewater.

It has struck me before just how much CO2 we actually make, mostly oblivious - a more average Australian than me makes 8,000 cubic metres/280,000 cubic feet of CO2 per year. 180 times my own body weight of CO2 per year, 1,800 times my weight per decade, enough I suspect, to make column of pure CO2 with my body's cross section that reaches halfway to the ISS each year. This is going on largely unnoticed in open sight, through an abundance of exhaust pipes and smokestacks, but it looks to me like CO2 is our single most abundant waste product.

Co2 is not a waste product, it is part of the carbon cycle, without it all plants and animals would die.  So how can you term it waste, when it is essential for life

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9 minutes ago, Olin said:

Co2 is not a waste product, it is part of the carbon cycle, without it all plants and animals would die.  So how can you term it waste, when it is essential for life

It's a waste product of the combustion process.

By your reasoning, excrement isn't a waste product because of bacteria and dung beetles. But waste is defined by the process in question; it's unused/unusable output of that process. In photosynthesis, oxygen is the waste product.

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1 hour ago, swansont said:

It's a waste product of the combustion process.

By your reasoning, excrement isn't a waste product because of bacteria and dung beetles. But waste is defined by the process in question; it's unused/unusable output of that process. In photosynthesis, oxygen is the waste product.

D

Fecal matter is a waste product to the animal that produces it, however it is necessary for other plants to grow, and since plants are the base of the food chain animal waste is actually food.  If you are so sure that co2 is the end of the earth, you might want to consider offing yourself to save the earth, as you are exhaling co2 now

Extra co2 is currently greening deserts

Edited by Olin

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1 minute ago, Olin said:

D

Fecal matter is a waste product to the animal that produces it, however it is necessary for other plants to grow, and since plants are the base of the food chain animal waste is actually food. 

Can you please be consistent in your logic? If it's necessary for plants to grow, it's not a waste product, according to your claim. (being wrong is bad enough, but to be inconsistent and wrong is worse)

1 minute ago, Olin said:

If you are so sure that co2 is the end of the earth, you might want to consider offing yourself to save the earth, as you are exhaling co2 now

Where did I say that CO2 is the end of the earth? When you can't get the basic facts right, going with hyperbole is pretty much the exact wrong thing to do. 

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2 minutes ago, swansont said:

Can you please be consistent in your logic? If it's necessary for plants to grow, it's not a waste product, according to your claim. (being wrong is bad enough, but to be inconsistent and wrong is worse)

Where did I say that CO2 is the end of the earth? When you can't get the basic facts right, going with hyperbole is pretty much the exact wrong thing to do. 

Again you seem to be unaware that we all live in symbiotic relationships.  Mammal fecal waste is nitrogen for the tomatoes that you might eat.

How do you not know this? 

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24 minutes ago, Olin said:

Again you seem to be unaware that we all live in symbiotic relationships.  Mammal fecal waste is nitrogen for the tomatoes that you might eat.

How do you not know this? 

I'm not sure how you reach that conclusion. I have only been focused on your mistaken comment and faulty logic. Seems wrong to think you can extrapolate from that, and tell me what I know and don't know.

Meanwhile, "waste product" is a term that is used in reference to specific processes and reactions. In thermodynamics, there is waste heat. Which has exactly zero bearing on the fact that some people are cold, and even freeze to death, or that the "waste heat" can be put to use elsewhere (called cogeneration)

 

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There is also the rather obvious observation that excess CO2 is in fact not taken up by plants. Otherwise the atmospheric CO2 content would not increase...

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13 minutes ago, swansont said:

I'm not sure how you reach that conclusion. I have only been focused on your mistaken comment and faulty logic. Seems wrong to think you can extrapolate from that, and tell me what I know and don't know.

Meanwhile, "waste product" is a term that is used in reference to specific processes and reactions. In thermodynamics, there is waste heat. Which has exactly zero bearing on the fact that some people are cold, and even freeze to death, or that the "waste heat" can be put to use elsewhere (called cogeneration)

 

Lol. Symbiotic relationships are not my conclusion.  In nature waste is recycled, and it is a vital source of nutrients.  How do you not know this?

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18 minutes ago, Olin said:

Lol. Symbiotic relationships are not my conclusion.  In nature waste is recycled, and it is a vital source of nutrients.  How do you not know this?

I do know this. I simply wasn't discussing it. It was outside of the scope of my response.

I might comment "How can you not know that things fall when you drop them?" because you haven't mentioned it in the discussion. But I won't, because that would be pretty stupid thing to do.

Meanwhile, "waste product" is a term that is used in reference to specific processes and reactions.

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1 hour ago, Olin said:

If you are so sure that co2 is the end of the earth, you might want to consider offing yourself to save the earth, as you are exhaling co2 now

!

Moderator Note

Our first rule is: Be civil

 

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If you are counting every gram of CO2 we release as waste, then you need to count every gram we cause to be fixed in the minus column. Soil erosion due to overgrazing leaves bare rock exposed to the elements. The weathering of the rock takes out CO2. In the Himalayas, mountains are being denuded due to firewood cutting, with the same result.

Farmers spread lime on their fields, in areas of acidic soil. That takes carbon out of the water and fixes it, in a similar way to weathering of rocks. There are lots of ways that we remove CO2, as well as adding to it. The use of timber in buildings takes it out of the bio cycle, at least for a while. More carbon fixed. Maybe more could be done to re-use timber at the end of it's life, or to use it for power generation. I'd like to see a ban on just burning it away on bonfires. 

On the minus side, the cutting down of forests to grow palm oil or for cattle ranching is adding hugely to the CO2 in the air, both by burning the spoil, and impoverishing the soil. 

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55 minutes ago, swansont said:

I do know this. I simply wasn't discussing it. It was outside of the scope of my response.

I might comment "How can you not know that things fall when you drop them?" because you haven't mentioned it in the discussion. But I won't, because that would be pretty stupid thing to do.

Meanwhile, "waste product" is a term that is used in reference to specific processes and reactions.

Millions of gallons of methane, ammonia and sulfur compounds pour into the oceans every day.  These far from being waste or toxic actually provide vital nutrients to the oceans

24 minutes ago, mistermack said:

If you are counting every gram of CO2 we release as waste, then you need to count every gram we cause to be fixed in the minus column. Soil erosion due to overgrazing leaves bare rock exposed to the elements. The weathering of the rock takes out CO2. In the Himalayas, mountains are being denuded due to firewood cutting, with the same result.

Farmers spread lime on their fields, in areas of acidic soil. That takes carbon out of the water and fixes it, in a similar way to weathering of rocks. There are lots of ways that we remove CO2, as well as adding to it. The use of timber in buildings takes it out of the bio cycle, at least for a while. More carbon fixed. Maybe more could be done to re-use timber at the end of it's life, or to use it for power generation. I'd like to see a ban on just burning it away on bonfires. 

On the minus side, the cutting down of forests to grow palm oil or for cattle ranching is adding hugely to the CO2 in the air, both by burning the spoil, and impoverishing the soil. 

We need to find more ways to add co2 to the environment. To green deserts

1 hour ago, CharonY said:

There is also the rather obvious observation that excess CO2 is in fact not taken up by plants. Otherwise the atmospheric CO2 content would not increase...

Sorry charon, co2 is absorbed from the air by plants.  How do you not know this?

http://theconversation.com/plants-absorb-more-co2-than-we-thought-but-32945

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11 minutes ago, Olin said:

We need to find more ways to add co2 to the environment. To green deserts

What we have done to soils has added huge quantities of carbon to the atmosphere and oceans. Overgrazing and firewood and fuel gathering has turned huge areas into desert and semi-desert, and there is now practically no carbon in the soils. It can be reversed by managing grazing, but a lot of the countries are so poor that it's not feasible without outside help. 

21 minutes ago, Olin said:

Sorry charon, co2 is absorbed from the air by plants.  How do you not know this?

Excess means the CO2 that's NOT absorbed by plants etc. How do YOU not know this?

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