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Does breathing contribute to CO2 buildup in the atmosphere?

What the science says...

Select a level... Basic Intermediate

By breathing out, we are simply returning to the air the same CO2 that was there to begin with.

Climate Myth...

Breathing contributes to CO2 buildup

"Pollution; none of us are supporting putting substances into the atmosphere or the waterways that might be pollutants, but carbon dioxide is not a pollutant. If Senator Wong was really serious about her science she would stop breathing because you inhale air that's got 385 parts per million carbon dioxide in it and you exhale air with about ten times as much, and that extra carbon comes from what you eat. So that is absolute nonsense." (Ian Plimer)

The very first time you learned about carbon dioxide was probably in grade school: We breathe in oxygen and breathe out carbon dioxide. Any eight-year-old can rattle off this fact.

It should come as no surprise that, when confronted with the challenge of reducing our carbon emissions from the burning of fossil fuels, some people angrily proclaim, "Why should we bother? Even breathing out creates carbon emissions!"

This statement fails to take into account the other half of the carbon cycle. As you also learned in grade school, plants are the opposite to animals in this respect: Through photosynthesis, they take in carbon dioxide and release oxygen, in a chemical equation opposite to the one above. (They also perform some respiration, because they need to eat as well, but it is outweighed by the photosynthesis.) The carbon they collect from the CO2 in the air forms their tissues - roots, stems, leaves, and fruit.

These tissues form the base of the food chain, as they are eaten by animals, which are eaten by other animals, and so on. As humans, we are part of this food chain. All the carbon in our body comes either directly or indirectly from plants, which took it out of the air only recently. 

This new animation published by Dr. Patrick T. Brown (Carnegie Institution for Science, Stanford University) in September 2018 explains the process:

Therefore, when we breathe out, all the carbon dioxide we exhale has already been accounted for. We are simply returning to the air the same carbon that was there to begin with. Remember, it's a carbon cycle, not a straight line - and a good thing, too!

Update information: This rebuttal was updated on September 12, 2018 to swap the graphic showing a - to some - "odd looking cow" with the new video we happened to notice on Twitter. Thanks to Patrick T. Brown for making it available on YouTube!

Last updated on 13 September 2018 by BaerbelW . View Archives

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Comments 51 to 100 out of 159:

  1. Hi Tom, thanks for the explanation and clearing up the definition of biomass. 

    My background is in engineering, not geology, so I'm by no means an expert on atmospheric CO2 exchange.

    There's is however one part of your explanation that doesn't make sense to me: -   

    "So, we add the human carbon input, which comes from food and all of which comes initially from the atmosphere. You then have a cycle in which the ouput (human respiration) is very slightly less than the input (human consumption of CO2 indirectly drawn from the atmosphere). 


    I don't understand why CO2 initially comes from the atmosphere. I would have thought it correct to say that CO2 in the atmosphere initially comes from biomass (respiration) or an external input such as vulcanism, and that the atmosphere is the transport media in the system.  

    Rather than take the thread OT I'll consult with a geologist friend of mine in the next day of so to get a better understanding of why the atmosphere is regarded as the starting point in the cycle. 

  2. Art Vandelay @51, there a couple of reasons to treat photosynthesis as the primary process (so that the CO2 is treated as initially coming from the atmosphere).  First, historically that is what happened.  Ie, before there were multicellular animals, there was photosynthesis, and indeed multicellular animals only became possible because of the existence of photosynthetic plants (or microbes) on which to feed.  Second, food consumption can be treated as a flow of energy from low entropy to high entropy.  As such the conversion from the lowest entropy energy supply generally available on Earth (sunlight) to the next lowest entropy source of energy generally available (sugars in plants) is the primary process.  So, thermodynamically photosynthesis (and hence extraction of CO2 from the atmosphere) is primary.

    However, these are not reasons directly related to the accounting of carbon flows.  For that purpose we can take several approaches.  The simplest approach, and the one in fact used by climate scientists, is to ignore churning.  That is, to only take account of change of carbon in biomass reservoirs.  If we account for carbon in that way, the human respiration is closely balanced by photosynthesis absorbing almost the same amount of Carbon.  As this is just churning, it is ignored, and the only thing that is accounted for is the slight increase in carbon storage in humans due to increasing population and obesity.

    Alternatively, you could consider human respiration as a relevant emission, but only if you consider all photosynthesis a relevant sequestration.  

    Looking at the IPCC graph I posted @42, we can either consider net land flux (=4.3 GtC per annum sequestered), or we can consider the two fluxes seperately, and say there are 118.7 GtC per annum emitted and 123 GtC per annum sequestered.  It makes no difference in the end.  What you cannot do is consider treat the total respiration as emissions, but consider only excess photosynthesis as sequestration, which is what the denier argument rebutted above tries to do.  That is similar to their similar dishonesty in suggesting anthropogenic emissions are very small because they are only 4.3% of total emissions because they are only 4.3% of total CO2 flux into the atmosphere while ignoring that the natural components of that flux are almost exactly balanced by natural fluxes from the atmosphere so that the net increase is entirely due to anthropogenic emissions.

    These figures are for the entire terrestial biosphere, but the same point applies to human respiration and the photsynthesis of the carbon content of human food.  Further, because that photosynthesis is a continuous process (as is the respiration), the two components almost exactly balance at any point of time, and certainly the time averaged processes do.  

  3. Tom Curtis@52

    Thanks for that detailed explanation, and particularly the explanation of accounting methods employed. It all makes much more sense to me now.

    My Geologist friend had a slightly different take on it, and not unexpectedly employed a different accounting method. Although he deemed the assertion that "human breathing causes atmospheric CO2" to be largely spurious, he also added that it's more relevant to examine changes to the biomass itself, and specifically the ratio of photosynthetic to non-photosynthetic biomass due to human population over a given timeframe. He thought that human activities such as deforestation through logging and burning were likely to be more influential on changes to atmospheric CO2 than human respiration itself - leaving aside the impacts of fossil fuel burning.

    Endeavouring to research further for myself, I found a paper that calculated atmospheric CO2 from human activities alone to represent 25% of total emissions; mostly the result of biomass depletion through deforestation, which depletes the photosynthetic pool. This highlights the fact that population itself will be a hindrance to efforts to remove excess carbon from the atmosphere in the coming decades, regardless of the emission scenario we eventually achieve, and future radical geo-engineering solutions are perhaps not out of the question.

    As an aside, CO2 from human respiration can be estimated with simple math, and works out to account for about 9% of global emissions – which admittedly looks like a big number in isolation.

    Which brings us back to the original skeptic’s assertion that “breathing causes CO2 accumulation in the atmosphere”.

    Rather than dismiss it as a myth, I regard it as an interesting claim that’s worthy of some examination, even if irrelevant in the discussion of (CAGW) climate change.

    Personally, if I was going to take a skeptic ’s position, I would assert that the current human population, and associated activities required to sustain it, will add CO2 to the atmosphere, with or without fossil fuel combustion.

  4. Humans sink Carbon through waste, Humans are producers by means of the increment in aricultural productivity per hectar which we have developed. Fossil fuel burning recycles sunk carbon like volcanoes do every so often. Humans are part of the biosphere increments in our population do increase co2 in the atmosphere through breathing alone. We do not produce all the food we eat, non farmed fish consumed by humans per year amounts to 70 million tons. the question of how much of the CO2 in the atmosphere comes from breathing is a valid one. in the end it is not just how much goes up and how much is sunk because we can't expect to keep earth on a permanent temperature indefinately as that would be imposible ue to prescesion of the earths axis. In fact trying to do o would probably harm the biosphere much more than fossil fuel burning. the adecuat balance of CO2 at any given moment in the atmosphere should be monitored as a percetage of total mas of living biosphere and in relation to the amount of C escaping the atmosphere aswell.

  5. I wonder... How much of the CO2 in the atmosphere comes from soft drink bubbles?

  6. juan vicini @54 & 55:

    1)  The CO2 in soft drinks is obtained by capturing CO2 from power station exhaust, and then forcing it into the water under high pressure.  Because the CO2 is captured from power station exhaust, the amount of CO2 in that exhaust is reduced by the same amount as the CO2 "emitted" by soft drinks.  In consequence, soft drinks emit no CO2 that was not going to be emitted anyway.  It causes no increase in total CO2 emissions, other than that due to the energy of manufacture.

    2) All human food is either plant life, or processed from plant life (meats).  As such, the CO2 in all human food is obtained from the atmosphere by photosynthesis.  Further, once respired, new food is grown by again taking CO2 from the atmosphere by photosynthesis.  As such, the respired CO2 from humans does not increase overall atmospheric CO2 levels.  It is only possible to imagine that it does by ignoring the photosynthetic half of the equation.  This is all explained very clearly in the original post above, and in the comments afterwards.

  7. 1. isn't most of the swallowed CO2 plus the amount of CO2 produced from digestive processes, absorbed by the intestine, therefore by swallowing power plant co2 through cola arnt we sinking CO2 into fat, is all CO2 in human food obtained from organic sources through photosynthesis, if not how much mineral carbon is in our food?


    2. If over all human population growth and the resulting increment in food intake translates into a net depletion of the top of the food chain (excluding whales who eat plancton directly) live biosphere in the oceans, wouldnt that translate into an overall increase in CO2 in the atmosphere resulting from incremental of human respiration? pound per pound does human respiration more eficient than fish respiration in terms of oxygen intake vs CO2 outflow?

    3. Humans are getting very close to applying C as a material to very "usefull" purposes, and more that any other technology out there CO2 recapture tech. will be most responsible for it given that it isnt just regular C laying about that is most useful, but rather the one that is excited to very high temperatures. Hopefully we wont depleate the atmosphere of CO2 then. 


  8. The notion that there is an eco balance to cancel respirated co2 and only co2 emissions from other sources should be considered is rediculous. There is no proof that the crops that replaced other disiduous plants that were growning on the ground before the crops were planted were or are any more efficient at converting co2 to o2. The real fact is that the yield of crops have largley been increased by improved germination, resistance to disease, irragation, and the control of pests as much as the number of acres dedicated to agriculture over the last 50 years. Those changes do little or nothing to affect the co2 consumption by crops. In the US farmland was allowed to remain unplanted in order to reduce food surplus and increase crop futures. The reason that we contiune to hear the bable from environmentalist groups about carbon emmissions is that they are more about self preservation. The notion that population control is the real answer to all these issues is unthinkable to them because for many of the leaders of this cause, that is where there power base comes from. The earth has a finite capacity for filtering out co2 strictly based on vegetation. Maybe we should be building co2 converters instead or shutting down coal if favor of nuclear power or trying to convert to wind which can only work if it was a globally connected power grid. That is decades or centuries away.


    Thank you for taking the time to share with us.  Skeptical Science is a user forum wherein the science of climate change can be discussed from the standpoint of the science itself.  Ideology and politics get checked at the keyboard.

    Please take the time to review the Comments Policy and ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter.

    In particular, please note the "No inflammatory statement and accusations of fraud".

  9. hydman1 @58, in all photosynthesis in plants, molecules of CO2 combine with molecules of water to produce sugar and oxygen.  This is the general formula:

    There are different pathways to achieve this reaction, but the initial and final reaction products are the same for all pathways.  Therefore there is no difference in the efficiency of plants in converting CO2 (plus H2O) to O2 (plus C6H12O6).

    What there is is a difference in is the biomass of different ecosystemts and/or crops per hectare; and hence a difference in the amount of carbon stored per hectare.  That difference, however, is accounted for under the rubric of Land Use Change (LUC).

    Building CO2 converters, ie, machinery that takes CO2 and seperates the oxygen from the carbon cannot (due to conservation of energy) use less energy than is produced by burning coal, and due to inefficiencies, will likely use substantially more.  Any such solution, therefore, cannot work without the majority of the economy being sustained by non-fossil fuel energy.  At that point, it would be simpler, and much cheaper to simply substitute the non-fossil fuel energy for the current fossil fuel energy use.

  10. 'By breathing out, we are simply returning to the air the same CO2 that was there to begin with.'

    As biological engines we consume energy and produce waste, given we live on a planet that has finite mass of elements with the only addition to the total mass coming from stellar objects the I think it's safe to say in it's simplest terms the statement is correct.

    CO2 measurements have been taken for many years and have been rising in concert with rising global temps with records extend back to 1850 showing a dramatic increase. Taking those temp records and using quadratic equation to extrapilate the curve of incidence, it shows that temp increases began before 1850, although incremently slower the trend was upward and this is before fossil fuels became popular, increasing trend can be attributed to increasing carbon based energy usage, which is directly related to and attributed to the increase in population.

    Dramatic increases in modern CO2 levels are directly or indirectly linked to man and his actions in most cases.

    A reducing biomass that converts CO2 to stored carbon coupled with mankind's increased CO2 producing enviroment and life suggest's the balances that we assumed as constants no longer apply.

    If we are producing more CO2 than the global environment can absorb then the outcome is obvious, if the environments that can absorb CO2 keeps reducing or slow's down uptake due to excess CO2 then problem further compounds global impact.

    If we were to compare increasing CO2 levels with global population increases we see much the same trend and increases as we see with fossil fuel usage if looked at solely.

    An increasing population does by breathing incrementaly contribute more CO2 gas to the atmosphere, which does contribute to global warming and rising temps, by the time CO2 is converted and stored as carbon it will added it's own impact which add's to rising temps. 

    CO2 is as a gas, a pollutant, we breath out more than we take in so we add to the combined total of CO2 increase, it is posionous or hazardous depending on it's concentrations to most living organism.......

  11. I dont see how we can "breath out more than we take in". We take C in via our food, and emit in breathing. While we live, we are carbon sink.

    The contribution of changes in biomass since 1750 is detailed in the AR5 WG1, p486, table 6.1.  The total land to atmosphere change is estimated at 30 PgC +/- 45. Compare that fossil fuel contribution of 375 PgC +/- 30.

  12. It doesn't look like DailySledge has read all the comments to this article. The comment that "An increasing population does by breathing incrementaly contribute more CO2 gas to the atmosphere" has already been addressed (e.g. here).

    Long story short, as scaddenp points out: more people store more carbon, so an increasing population has to be a carbon sink, not a source.

  13. DailySledge @60, the industrial revolution started in 1750, not 1850.  As a result, from 1750 to 1849, industrial emissions of CO2 from the burning of coal amounted to 1.25 billion metric tonnes of Carbon.  While only, approximately, a sixth of current annual industrial emissions, it still represents a substantive contribution to global warming.  The contribution from Land Use Change was approximately the same as that from fossil fuel consumption in 1850 (spreadsheet), and is likely to have exceeded it beforehand.  Together, these contribute to an annual increase of 1.3 ppmv in CO2 concentration over the period 1750-1849.  However, probably more significant was the significant reduction in volcanic activity over the period, combined with an increase in solar activity.  So your quadratic fits retrodiction of a positive temperature trend prior to 1850 is accurate as far as that goes, but misleading in that there have been substantial changes in the importance of different forcings over various intervals within the quadratic fit.

  14. It's a bit of rhetorical sleight of hand to appeal to the carbon cycle in order to claim that human breath is neutral, since the factor that should be taken into account is that human consumption negates the collection of carbon performed by those plants that are used for food, in addition to deforestation for conversion into agriculture. The impact of human consumption and breathing is that the sink that would naturally be functioning ceases to operate when human consumers are eating it. That biomass (now negated through its function as food) is precisely the kind of sink that stripped atmospheric carbon long ago and created the fossil fuel deposits, which are currently being liberated through human activity back into the atmosphere.


    [PS] Changes/carbon loss from vegetation change is accounted for under "Land Use Change".

  15. For clarity's sake: it appears the role of human respiration ("Does breathing contribute to CO2 buildup in the atmosphere?") wrt CO2 buildup amounts to a zero sum when including photosynthesis. In essence this describes a natural sort of equilibrium.

    I completely agree insofar as the science itself goes (and the provided formulas-thanks)

    Pragmatically -somewhat referring to #64 response (Pointfisha) above- the population of humans is increasing alongside deforestation, excluding deforestation where it is a consequence of industrialization.

    This seems to indicate that mass consumption of meat (specifically beef & lamb) has a significant impact on climate.

    I guess I am asking what an acceptable human population would be, assuming pre-1750 (pre-Industrial Revolution) technology, in keeping with keeping CO2 levels static or reducing them from current levels. Another way of asking this: at what population will human respiration outstrip the capacity of photosynthesis?

    I do realize my query is flawed in that is purely theoretical, and perhaps even dumb: excludes other natural sources of CO2 (vulcanism, animal respiration) but those variables seem outside the scope of this article.

  16. MDMonty @65, IMO it is dubious that a preindustrial revolution technology could sustain population levels at even a quarter of current levels.  Primarily that is because it would not be able to sustain the vast energy inputs into food production; but also because the much slower transport speeds would necessitate the majority of food consumption to be from local or close (over sea) distances.  The UK may be able to source wheat from the US, for instance, but not most vegetables or fruit, and not much in the way of meat; simply due to spoilage.  A sustainable population level at those industrial levels would be in the order of half to a billion people.

    More interesting is the sustainable population at current, or likely near future technologies.  I think the evidence is that we have already exceeded it, though primarilly due to the proportion of land committed to food intake, plus the overfishing of the oceans.  Simply as regards global warming, we can sustain the current population on  greenhouse free energy and transport system, possibly at a higher standard of living than is currently common in Western Countries.  That, however, requires a major effort to transition; as the current population with the current energy mix is clearly unsustainable.

  17. @ 66 Tom Curtis,

     You seem to be mixing science and technology with industrialization. Not all technology is industrial in nature. This is important to remember in agriculture.

    The other important thing to remember is that counter intuitively, biological systems yield more when not overused. For example, a fishery that is overfished, yields fewer tons of fish per year than a fishery that is not overfished. Grassland that is overgrazed yields less meat per acre per year than grassland that is properly grazed. Forests that are over timbered yield less wood per acre per year than forests properly managed. We are so wired into net sum zero thinking that people often miss that.

    So yes, agriculture (including fisheries) could sustain populations much higher than we currently have, even though the current population already exceeds carrying capacity. We simply need to use holistic systems models of production instead of net sum zero industrial models of production.

    Don't get me wrong. Industrial models are very good at some things. But when it comes to biological systems, far from ideal.

  18. RedBaron @67, the current population is approximately 7.4 Billion, so that my estimate of up to a quarter of that sustained using preindustrial (ie, pre 1750) technology represents a population of up to 1.85 billion.  That is 2.64 times the 0.7 billion population in 1750, so I am certainly allowing for some advances in non-industrial technologies.

    Having said that, I do not think you are giving serious consideration to the difficulties involved.  A preindustrial fishing technology is restricted to small (because of limited work force) wooden, sail powered vessels.  Such vessels cannot fish with long lines, nor trawl, nor drift net.  Nor can they fish the deep ocean, and increasingly important source of modern fish.  Further, they cannot operate more than about a weeks distance from port, and typically will operate within a few hourse sailing from port.  Given those limitations, catchable fish will be a very small fraction of currently available, even with a rebound of fish stocks.

    Or consider grain growing, with no combine harvesters; with plows being of wood construction with (at best) a cast iron plate to restrict wear on the blade, and drawn by oxen or (hopefully) horses.  Harvesting will probably be by scythe.  These factors required something in the order 60-80% of the population to be agricultural workers, just to provide enough food for all.

    Or consider that such heating fuel we use will be in the form of charcoal, requiring extensive forests over much that is now agricultural land.

    And that leaves aside questions of spoilage, famine and drought.

    There is often a ridiculous optimism by some people who, urban dwellers nearly all, and with no knowledge of history, suppose that we can get rid of industrialization to advantage.  But life before industrialization was nasty, brutish and short.  In general, excepting the upper middle class and above, hunter gatherers lived better than the vast majority of even 19th century populations, but only by dint of a very low population per unit area.

  19. @ 68 Tom Curtis,

    Exactly correct Tom. Industrialization has improve some things dramatically. No farmer wants to give up his tractor etc..., except maybe a few Amish who do without. Industrialization has given us tools. It's how we use those tools that make all the difference. If when we treat those biological systems on which we use those tools to harvest food and fiber as a net sum zero product, (ignoring how fundamentally different biological systems function), then that's when we have problems with unsustainability. Which is just the flip side of the overpopulation coin.

    At lower population levels we didn't have this problem because we could always move on to new untapped areas when the areas we were harvesting from collapsed, like you mentioned with fishing. The collapsed areas would recover over time and we could come back to them later in many cases.

    However, now we must fundamentally change the production models. We no longer have to option of overuse, abandonment/fallow, and returning decades or centuries later. Instead we must change the production models to methods using holistic systems science and modern technology appropriately applied.

    If we take current productive land/fisheries etc. and change the production models, we can regenerate the ecosystems services on that land/fisheries. We also can return to currently abandoned areas and apply these new system science based regenerative models to them as well, returning them to productivity.

    So actually when you add the current productive land/fisheries to the abandoned land/fisheries that collapsed earlier due to over use, we can actually increase the total population they can support sustainably long into the distant future.

    A great working example of this is China's Loess Plateau Project. This land was destroyed by agriculture and could no longer support much population at all. Since beginning to restore the land, the amount of food and fiber produced has increased every year. The amount of carbon sequestration has increased every year. The runoff water quality has increase every year. The wildlife and biodiversity has increased every year. When you change the production models you see profound differences.

    In the USA a similar revolution in thinking is also being taught and is in its infancy. Best exemplified by this quote from the USDA-NRCS.

    "When farmers view soil health not as an abstract virtue, but as a real asset, it revolutionizes the way they farm and radically reduces their dependence on inputs to produce food and fiber." -USDA (Author Unknown)

    I am an organic research farmer. I am not afraid of change. I am the change.

  20. RedBaron @69, I understand from your comment that it was my second paragraph @66 that you disagreed with, not the first.  In particular you disagreed with my assessment that:

    "More interesting is the sustainable population at current, or likely near future technologies. I think the evidence is that we have already exceeded it, though primarilly due to the proportion of land committed to food intake, plus the overfishing of the oceans."

    That may, in part, be due to a disagreement about what is mean by "sustainable".  I have no doubt that we can increase food production into the future sufficiently to support the most likely peak world population of about 11 billion people:

    (See also this)

    I do not doubt we can do so and maintain ecosystem integrity in the limited sense that O2 production and soil health will not be impared, and a new stable ecosystem will develop.  But it will be a stable ecosystem similar to that of Britain's, in which all of nature is shaped by man, and there is no room left for most of the native mega-fauna - particularly predators (such as the bears and wolves that used to be native to Britain).

    It may be that is what the world population really desires.  It is certainly true that absense make the heart grow fonder when it comes to large predators; and that humans in the end will have no place for lions, tigers etc, except in zoos.  The same is true for large grazers, other than those dedicated for human consumption.  But I hope we have more space for nature than that, and that would require that we produce the food for the 11 billion on less land than we currently have under agriculture, not more.  

    What is more, with rising economic expectation in the third world, we need to factor in an increase in food consumption per capita by about 30-50%, and an increase in food quality (ie, more protein and fresh fruit and vegetables).  This is particularly the case in Africa where most of the population increase is expected to come.

    All in all, this means we need a increase in food production per hectare by about a factor of two for current populations (assuming 70% loss of agricultural land to allow for a wild nature), and near three for projected future populations. 

  21. @ Tom Curtis # 70

    You said, "All in all, this means we need a increase in food production per hectare by about a factor of two for current populations (assuming 70% loss of agricultural land to allow for a wild nature), and near three for projected future populations."


    I am nearly 100% certain we could do exactly that and very likely more on 1/2 the land currently under agriculture. Probably not England. It is an Island. But in the North America, most of Asia and Africa? I would bet my bottom dollar we can. And I am not just saying that without evidence either. The current industrialized models of production in agriculture are that inefficient in land use. The models are designed to be efficient in other things, not quantity food produced sustainably per hectacre. In fact in some things like the CAFO buisness model, it was specifically designed to be inefficient on purpose as a buffer stock scheme. This from Wiki:

    Most buffer stock schemes work along the same rough lines: first, two prices are determined, a floor and a ceiling (minimum and maximum price). When the price drops close to the floor price (after a new rich vein of silver is found, for example), the scheme operator (usually government) will start buying up the stock, ensuring that the price does not fall further. Likewise, when the price rises close to the ceiling, the operator depresses the price by selling off its holding. In the meantime, it must either store the commodity or otherwise keep it out of the market (for example, by destroying it)

    The more inefficient the better. Biofuels has the same purpose. The idea is to purposely over produce grain because although an inefficient use of land, it can be stored. Then unlike many buffer stock schemes, instead of destroying the surplus, you waste it as inefficiently as possible on livestock or biofuels. The system does work in what it was designed to do. But in no way can you estimate the land needed to feed the world's population based on that type of system. The system was designed for a world where land was seen as practically limitless. Now within that system, production is incredibly efficient. But the system itself was designed to be an inefficient use of land, to fit the buffer stock scheme instead.

    The very first thing you could do to  approximately double the food produced per hectare is reintegrate animal production back on the crop farmers land. Then of course they must be properly managed, but there are countless ways to do that without lossing any crop yields at all, and sometimes increasing yields. Remember in industrialised countries like USA over 1/2 the arable cropland goes for producing animal feeds and biofuels. Just by going to a forage based system integrated into the arable cropland you reach that food production goal of "factor of two for current populations" right away. In fact probably would be too fast. Might have to first switch to forage based regenerative systems, to repair the non-arable grazing land first, and gradually remove livestock as wild populations of animals rebuild their numbers in the newly restored habitat. Those removed domestic animals placed gradually into the integrated arable cropland as they are removed from rewilded land. If you took them away too fast the non-arable land would be undergrazed and either recover too slowly or even sometimes degrade even faster.

    It a bit hard to really explain it all on a forum like this. But I can say that IMHO we could do exactly what you asked with our current technology and at the same time actually sequester 5-20 tonnes CO2 per hectare per year into the long term stable soil carbon pool. And there are lots of case studies that show this from all over the world.

  22. RedBaron @71, I will bow to your superior knowledge of farming.

  23. This rebuttal is missing something. It says that people arguing that breathing causes CO2 are missing the other half of the cycle.

    By that very same logic, those who are saying we should cut down on fossil fuel use are missing the other half of the cycle — those plants that created the fossil fuels also took that CO2 out of the atmosphere hundreds of thousands of years ago. This is all a cycle and if it happens, it happens. You can't stop it. 

  24. Mochan

    Nope. More like 100's of millions of years ago. Plants removed vast amounts of carbon over huge timescales and it has been locked away ever since. Plants today work on a carbon cycle that doesn't include that sequestered ancient CO2. So adding this carbon from long ago is disrupting the balance of that system.

  25. Lets not get into handwavy arguments. The relevant diagram is already on this thread here. Long term burial of carbon by plants etc takes place at rate about 0.2Pg C per year. Emissions from fossils fuels and land use change are about 9Pg C per year.

    Not to mention the obvious fact that CO2 levels in the atmosphere are rising, and that the isotopic composition of CO2 in atmosphere is consistent with addition coming from FF.

  26. One thing to consider in the argument that the biosphere is still in balance with 7 billion humans is that 20% of food consuption is from the oceans, not land. In other words, 20% of the 3Gt CO2 exhaled by humans was not part of the normal terrestrial cycle. It's also true that not all food is derived from a source of photosynthesized CO2. 

    Also, to what extent is balance achieved by the burning of fossil fuels - which increases photosynthesis as a feedback response?

    If the existing balance is only made possible by virtue of 400ppm CO2 in the atmosphere, the current population is obviously not sustainable in the long term.   

    Based purely on the amount of CO2 exhaled by humans it should be possible to calculate a population level that's sustainable with a photosynthesis rate commensurate with around 280 ppm atmospheric concentration.  Based on flux apprximations from the IPCC it would appear that we're already beyond a sustainable population maximum. 

    One last point is that 7 billion humans doesn't actually sequester much in the way of C when compared with plants. There's approx 25kg of carbon per human, so <0.2Gt for the entire population.   

  27. Art Vandelay @72, nearly all, if not all sea food eaten by humans are situated in a food chain with photosynthesis at the base.  Ergo, while the exchange of CO2 for oxygen that drives the process may not take place in the atmosphere, it still occurs.  As pCO2 equilibriates between the atmosphere and surface waters in less than a year, that means most of the marine food eaten by humans has no significant effect.

    I am not aware of any human from non-organic sources, or from archaea, so if you want to claim that "food is derived from a source of photosynthesized CO2" is an appreciable source of human food, you will need to provide references.

    The difference in biomass between humans and plants is accounted for in the Land Use Change (LUC) budget in the global CO2 budget.  It is smaller than you think because the biomass of large herbivores (ie, cattle) has massively increased over the last 160 years.  Identifying just a single component in the changed system and comparing it with the total biomass of the preceding system is misleading, though no doubt unintentionally. 

  28. What a fantastic site, as an interested amateur please correct me if I am wrong, but the way I see it all today:

    When water was first created on Earth the environment centred just under boiling point and eventually became tropical with the creation of plant life. 10,000 years ago humans began to upset the carbon cycle by farming and successfully delayed the next ice age, although ice ages are one way to redistribute minerals leached away by farming Hence the lush forest in pre historic times.

    In the last 50-years farming has changed globally. Look at our fields and you will see that a good proportion of the year they are clear of vegetation. Many of our crops are fed hydroponically in polytunnels with nutrients, and field crops use fossle fuel based fertilisers. Worst of all beneficial soil microbes that consume the plant sugars in order to extract nutrients are killed off with herbicides and pesticides as no longer required. one type of microbe burrows into a plant root in order to feed on the sugars from the 8% of carbon extracted between the night/day CO2/Oxgen cycle These particular microbes increase the water take up area of a plant root by 1000x, just think how much nutrient solution or fertiliser is required to account for the microbes lost. This is huge if considered world wide.

    I have a book that recorded Brinks Manometer readings in 1940 that shows that the sugar levels of ripe tomatoes in 1940 are only 10% of best grown organic today, which is an indication of ripeness and mineral content indicating how we are all so well fed while starved for nutrients. This book is ex-library so goodness knows what today's figures are. As I just retired this year and have bought a manometer I intend to start monitoring and tests on my allotment, this is a good forum to discuss the results.

    There is a growing interest in no till farming, using companion planting, organic methods, and green manures with permanent clover keys to sequester carbon from the atmospher. A great book on this is "The one straw revolution". All those ploughed brown fields would over winter with a green manure made from CO2, which fixes nitrogen, and is then retained within the soil when ploughed in.

    Another change to our climate is being caused, so I read, by desertification. See the Savory Institute web site. They will show you how a desert is formed in just a couple of years when animals are removed from the land, elephants are culled or domestic cattle are wrongly farmed standing around in fields. Carbon sequestration from recovery of a desert using just cattle and mob grazing is equivalent to 6000 car emissions/acre (please check this figure yourself on the Savory website). There is a great movement in the USA and UK towards mob grazing techniques, and when you compare the root size of say a Rye grass lay using mob grazing, soil improvement, with cut and digging in rather than ploughing out, you can see first hand where the CO2 is going, or at the moment not going. Even composted it releases CO2 back into the air along with other far worse greenhouse gases.

    This is such a complex topic, my belief is if every aspect is altered just 5% it will make a vast improvement. We all have to do our bit, everyone is correct in their beliefs.


  29. Correction: Brinks values are today 10% of 1940 figures. Sorry.

  30. @78 MLDonoghue

    Sorry to say, but just about everything you wrote is partly wrong and partly right. It's as if in a carefully constructed Poe of partial understanding but failure to grasp the bigger picture. If it is a Poe, I suggest you try just saying what you really mean and forget the low brow humor. 

    If it is not a Poe, then pick one subject and stick with it alone long enough to get a general understanding of that one single thing before you move to the next. Right now you have a tangled up mess of 1/2 truths like Gordian's knot.


    [PS] I think it is safe to assume this is not a Poe. Please be careful not to make responses that could create unconstructive flamewars. Better to simply point out what you think are some of the bigger errors and let discussion continue from there.

    MLDonoghue - while not  a gish-gallop of our more usual sort, you do cover a lot of territory and RBs advice to stick to one point at a time is sound.

  31. My sincere apologies to the Mods and MLDonoghue. I guess what I can say is context is everything. MLDonoghue, get your context right and I will try and help you best I can. For example the way you got it all out of context, it appears as if you think that ice ages recycle farming runoff.

  32. Tom Curtis @ 77, The difference in biomass between humans and plants is accounted for in the Land Use Change (LUC) budget in the global CO2 budget. It is smaller than you think because the biomass of large herbivores (ie, cattle) has massively increased over the last 160 years. Identifying just a single component in the changed system and comparing it with the total biomass of the preceding system is misleading, though no doubt unintentionally.

    That's true, it was wikipedia sourced, though the ratio of terrestrial plant / animal biomass is supposedly still approx 1000 : 1. 

    I was surprised to learn that large domesticated herbivores do constitute about 6x the biomass of humans, but It would be interesting to know how much biomass has been lost with the extinctions and depletions of various animal species as a consequence of human population growth. Such numbers are hard to come by. 

    From a book titled "Harvesting the biosphere", where the author has researched as best he could the various human impacts dating back to pre agricultural times,  it's stated that roughly 200 Gt C of global phytomass has been lost since about 1800, which is considerable given that it represents as much as 60% of fossil fuels burnt over the same period.

    It's postulated that as much as 40% of (post glacial) phytomass has been removed by humans. 

    If as projected, the global population will rise to 10 or 11 billion before 2100, the task of reassimilating all of that displaced carbon (from land clearing and FF combustion) back into the biosphere will not be a simple one, particularly if future land clearing increases phytomass loss for the purpose of increased agricultural output, human settlement, or even biofuel production.

  33. Art Vandelay @82, it is hard to estimate lost phytomass, and I will not try.  I do know that LUC including deforestation has resulted in anthropogenic emissions of 157 GtC (2015 Global Carbon Budget), and that about 50% of the dry mass of wood is carbon, and about 50% of the wet mass is H2O, so that the total wood lost is on the order of 628 Gigatonnes.  Against that, forest regrowth, increased growth due to moister conditions and the CO2 fertilization effect have increased net fixation of carbon by photosynthesis, so that the net change in carbon flux from vegetation is 0.2 GtC per annum (1.1 GtC/annum from LUC - 0.9 GtC/annum increase in net photosynthesis).  If that ratio was consistent through out the post 1850 era, that means the net change in vegetative biomass is on the order of 114 Gigatonnes (28.5 GtC).  That is a big "if", however, and I do not know of any research showing to what extent it holds or not.  I suspect, but do not know, that the net biomass lost is somewhere in the 200-300 Gigatonnes range.

    With regard to the biomass of mammals, we are no more secure grounds.  It has increased around 1.2 Gigatonnes:

    Assuming the 18% carbon content by mass of humans is typical of mammals, that represents 0.22 GtC, not to far from your humans only estimate.  That amount will be included in the uncertain change in net biomass consequent in the difference between LUC and cumulative net increase in photosynthesis.  Clearly animal biomass changes, human or otherwise are an insigificant fraction of the changes in vegetation, so my drawing attention to the change in large fauna biomass was an unintentional diversion.

  34. Tom and Art,

    You could also try to estimate fish biomass changes which would be very difficult.  Reports that there were so many cod that ships were slowed in sailing by the friction on the fishes backs indicate much loss of fish.  During World War II fish mass increased, possibly contributing to the hiatus in in warming in the 1940's.  Whales were also much affected.

  35. I am not sure if this is what you are looking for, but Vaclav Smil has some numbers in his article "Harvesting the Biosphere: The Human impact", 2011.  (a free copy is available on his homepage, but it seems to be offline at the moment;)

    Here are some numbers from Table 1, p 616:

    Year -  Population (million) - Global phytomass stock (Gt C)

    0 - 200  - 1,000
    1000 - 300 - 900
    1800 - 900 - 750
    1900 - 1,600 - 660
    2000 - 6,100 - 550

     The changes in zoomass are quite smal in comparison (p 618f):

    " The total zoomass of wild terrestrial mammals ... yields no more
    than about 50 Mt of live weight (about 10 Mt C) in 1900 and 25 Mt of live
    weight (about 5 Mt C) in 2000, a decline of 50 percent. In contrast, during the same time, the global anthropomass rose from roughly 13 to 55 Mt C."

    His estimate for the biomass of domestic animals is 35 Mt C in 1900 and 120 Mt C in 2000.

  36. michael sweet @84, fish are tricky.  

    Unlike the case with land animals, where we eat herbivores, humans preferentially eat large, predator fish.  The consequence is that while we fish down stocks of our preferred fish, the resulting lack of predators allows an increase in the number of prey fish.  This 2014 study indicates that we have reduced the biomass of predator fish by 66.4 (60.2-71.2)% over the last 100 years, with most of that occuring in the last 40 years.  Over the same time, however, the biomass of prey fish have increased by 130%, ie, more than doubled.  Given the trophic pyramid, the biomass of prey fish in the undisturbed state was likely 10 times that of the predator fish, giving a net change in biomass of 0.9*2.3 + 0.1*0.34 = 2.1, so that overall fish biomass may have approximately doubled.

    Of course, the increase in prey fish will also have resulted in a decrease in the biomass of their prey, ie, plankton.  That is difficult to estimate, however, because:

    1)  The population of prey fish were initially predator limited so that the biomass of planckton would not have been approximately 10 times that of the prey fish as according to the standard trophic pyramid; and

    2)  The prey fish often fed on zooplanckton which fed on phytoplanckton; and to the extent that is the case phytoplanckton would have become more numerous, possibly resulting in an overall increase in ocean biomass.

    To further complicate things, a recent study has suggested that fish numbers in the middle layer of the ocean (mesopelagic fish) have been underestimated.  As mesopelagic fish have not been primary catches in global fisheries until recently, the numbers quoted above may be overestimates by an order of magnitude.  

  37. If we are to assume that humans only recycle Carbon without adding any, and fossil fuels are not part of the cycle anymore, it begs to asks the question "where all the carbon came from before it became fossil fuel".?

    If carbon in CO2 (now stored in fossil fuels) was in the atmosphere to start with, how come the planet cooled down?  Thanks for simple answer, I am not Scientist.

  38. GB... For starters, carbon is the sixth most abundant element in the universe but that's very different than the "carbon cycle" being discussed here. The carbon in fossil fuels was part of an ancient carbon cycle from millions of years ago that has since become sequestered in the earth's crust. Fossil fuels (or "hydrocarbons") are ancient plant and animal life.

  39. GB @87, first, the Sun is gradually getting warmer over time.  The formula that describes its rate of warming is:

    L(t)/L(c) = 1/(1+2*(1-t/t(c))/5)

    Where L(t) is the luminosity at time, t, L(c) is the current luminosity of 3.85 *10^26 Watts, t is the time in Gigayears from the formation of the Sun, and t(c) is the current time since the formation of the Sun, or 4.57 Gigayears.

    Using this formula we can calculate that to maintain the same temperature as we had in the preindustrial, in the Carboniferous (when most coal, and hence most fossil carbon was laid down) we would have required an extra 700 ppmv of CO2 in the atmosphere to maintain preindustrial temperatures.  100 million years ago (the approximate age of most oil (but see also the age of the Tethys sea, were most middle eastern oil was laid down), we would have required an additional 130 ppmv of CO2 in the atmosphere.

    Of course, CO2 pumped straight into the atmosphere does not simply stay there, but over time, achieves equilibrium with the ocean, and with the chemical weathering process.

    That means to achieve a stable eqilibrium the actual amount of CO2 not locked up in fossil fuels would have had to be 4 or more times the 830 ppmv indicated just by considering insolation.  Allowing for the much faster chemical weathering prior to the carboniferous (ie, when there were no land plants to slow weathering) it would have been much more.  And more still again to account for the fact that in the Carboniferous and earlier, the Earth was warmer than it currently is.  Although an exact calculation of the amount of CO2 locked away to balance these factors is not available, these back of the envelope calculations show the magnitudes are in the right range.  

    More exact (but still approximate) calculations using carbon cycle models reproduce the history of Earth's temperature quite well, given known changes in CO2 concentration:

  40. Sorry,  but it seems a rather simplistic approach to assume the result would neccesarly be net neutral in terms of emmissions.  Yes, we've obviously grown more crops in order to consume them.... but that would have to assume the land upon which the crops were grown was absent of vegitation wouldn't it?  

    The assumption seems to be that we've increased the total amount of vegitation exactly enough to offset our increased respiration.... but haven't what we've actually done is CHANGED THE TYPE of vegitation from a form we can't consume to a form we can consume.

    Where is the evidence to suggest that we've actually increased the total mass of vegitation in an amount exactly equal to our respiration?

    Further wouldn't that also assume that all plant mass has exactly the same value in removing carbon from the atmosphere and acting as a carbon sink.  Just the fact that certain plants have longer life cycles and hold onto their mass for longer periods of time.... or have different growing cycles would tend to suggest otherwise wouldn't it?

    Would even a deciduous tree have the same value in removing carbon from the atmosphere and producing O2 as a conifer occupying the same acerage?

    That's even ignoring the role of livestock in the cycle and assuming all our intake comes directly from plants.

    I'm not a scientist but it seems rather like you've made a convenient set of assumptions of net neutrality for something that is not nearly as simplistic.... but maybe I'm completely off base.


    [RH] Note that all caps isn't allowed here. Thanks.

    In terms of your question, first, make sure you've read both the basic and intermediate tabs for this topic. It seems to me that you're trying to make the question more complicated than it is. This topic isn't intended to address land use changes due to population growth. For that you can read this SkS article.

  41. Thanks for your rapid response and I aplogize for the use of capitals. I was just trying to denote emphasis.

    I think the problem I'm running into is simply this.  The claim is that an increase in the numbers of humans engaging in respiration has a zero net effect on the level of CO2 in the atmosphere because that is offset because we produced more crops which themselves take in C from the atmosphere and thus results in net zero change.

    In theory if the only things you were considering were plants consumed and human respiration (and I suppose storage of C in tissues) in isolation... that argument would seem to make sense.

    However,  just as the Carbon we exhale comes from somewhere (consumption of plants) and our respiration should not be looked in isolation from that so too do the crops we produce to eat come from somehere and our production of them has some effect beyond thier simple consumption.

    In other words, I think what you are categorizing as land use change is salient to the topic being discussed and should not be artificially isolated from it.

    That is to say, if we weren't burning any fossil fuels whatsoever but still somehow performing all the other activities we perform in order to produce the food that we consume and which in part we respirate out as CO2 waste would the effect on the composition of the atmosphere be nothing whatsoever? Would the composition of the atmosphere be exactly the same as if there were no humans on the planet doing those things? or if there were only 1 billion. I really don't see how that would be a given.

    I can see the argument that the change might be very small compared to fossil fuel production, maybe even reach some equilibrium but would it be exactly the same equilibrium as were there no humans on the planet. I really don't see how you could make that argument?


    [RH] Again, you're extending the issue into other topics outside whether breathing adds CO2 to the atmosphere. Re-read the myth statement at the top of the article. That is what is being discussed. It's a very common misunderstanding that many non-scientists have regarding climate change and CO2 levels.

  42. Grumpymel @91 and 92, the claim above is a rebutal of denier claims that human respiration is a direct source of the increase of atmospheric CO2, just as is the combustion of fossil fuels.  That claim by deniers is typified by the quote from Ian Plimer, that

    "If Senator Wong was really serious about her science she would stop breathing because you inhale air that's got 385 parts per million carbon dioxide in it and you exhale air with about ten times as much, and that extra carbon comes from what you eat."

    Of course, if Ian Plimer was at all honest in his science (on global warming) he would have noted that the carbon in what we eat comes from CO2 in the atmosphere, and consequently Senator Penny Wong's, and our respiration causes no direct increase in CO2 concentration.

    That is a seperate question as to whether or not human agricultural activity has changed atmospheric content.  It has, and in complex ways.  Of these the most important have been the increase in CO2 from deforestation, and the increase in CH4 from rice farming and cattle production.  Nothing above denies this, and there is extensive discussion of this in comments above.  Further, the IPCC takes account of CO2 and CH4 production from these scources.

    For what it is worth, CO2 emissions due to Land Use Change (the title given to those emissions) represents about 10% of emissions from fossil fuel use and cement manufacture (another important source).

  43. I've been reconsidering this for a bit now and I think Plimer actually has a point about exhalation contributing to GW in a minor way. Hear this out. I know that carbon is a cycle but at only one point in that cycle is it acting as a GHG in the atmosphere. What actually determines how much warming GHG contributes to at any point is how much is in the atmosphere at that point, correct?

    If something happaned to increase the percentage of time that carbon spent in the atmospheric portion of it's cycle then that would increase the amount of carbon in the atmosphere at any given time and if the factor that caused that change were persistant rather then transient, the amount of carbon in the atmosphere at any given time would be consistantly higher as well, correct?

    For example, if hypothetically, at base line carbon spent 50 percent of it's cycle in the atmosphere and 50 percent in the non-atmospheric portion and some factor came along to change that ratio to 90 percent of it's time in atmosphere and 10 percent out, we'd have significantly more GHG in our atmosphere, correct?

    So the question, it seems to me, is "Does human consumption of carbon increase the amount of time it spends in the atmosphere?" or perhaps more directly "Does eating an apple return it's carbon to the atmosphere more rapidly then had we not picked it, let it fall to the ground, decay and rot"? Given what human consumption does to an apple compared to what would happen via natural decay...I'd have to say the answer was likely yes. We significantly decrease the amount of time it takes for carbon to return to the atmosphere.

    That doesn't mean that exhalation is a major factor in climate change but I'd have to say that yes, more humans on the planet consuming food and exhaling carbon back into the atmosphere probably does result in a consistantly larger amount of carbon in the atmosphere then if we weren't engaged in such activity.

  44. Grumpymel @93.

    Your argument only works if you assume that an apple (or other plant-matter that would grow and decay in its stead) somehow does not emit CO2 when it decays. An apple contains carbon and oxygen so as it decays, what happens to the carbon and oxygen? Is it only humanity that by eating apples and other food breath out CO2?

  45. Since I addressed this very topic at length in my YouTube video  I will only spend a couple of moments addressing the main subject of this thread.

    1.  As we breathe in 400 ppm CO2, we do not exhale "about ten times that amount", so the premise is incorrect.  We exhale some 100 times that amount, about 40,000 ppm (4% CO2).

    2.  It is not a few cows that have CO2 (and I didn't even consider the trivial issue of flatulence that so fascinates the AGW humorists), but all the herds of animals, and all terrestrial animals, including rodents and insects, that contribute CO2 to the atmosphere.  Indeed the mass of all other living things on land far exceed and far exceed in CO2 production, human exhalation.  I had no basis for calculating marine sources, and for that matter did not include the direct release of CO2 by oceans, springs, grottoes or even volcanoes.

    3.  The CO2 production that I found in my meta study as shown in the video was growing, and growing at the same rate as the CO2 reports put out by IPCC showed (what a surprise as the curve is the same shape for human population growth), but *they focused entirely on industrial production* in intentionally misleading people imo, and my data showed that the total terrestrial animal production was 40% as large as that produced by industry.  It's a sum because the industrial production data is well developed and not dependent on measuring Mauna Loa, and the other calculations are straightforward as well, so there's no confusion of what's a total produced (with my limitations as shown) and what's reported by measurement at 13000 feet.

    4.  Nor is it to be fobbed off as just part of the carbon cycle...ALL carbon comes from other carbon...but if the CO2 is being ascribed a causative action  (a la Anthropogenic Global Warming theory by IPCC), then ALL the sources need to be accounted for, not just some summary presumption (I say presumptuous, tendentious, presumption), if for no other reason than to modify any so-called "forcing" effect, which if it operates at all, does not do so only in response to industrial CO2.


    See the video. Ask questions there or here as you see fit.  Just one more thing. [snip]  I am not the first person on this thread to doubt some (or all) of the not-so-skeptical-science of the blog, but I see that they have disregarded those comments and not changed a thing. Is it characteristic of "skeptics" to be hardened in their skepticism, or is it that they call themselves skeptics as a false-flag clickbait hewing to the AGW belief system?  FWIW, I will be keeping a copy of this post in my file in the (unlikely) event that it somehow violates the Comments Policy, by its contradiction of skepsci's assertions.


    [RH] I would suggest that you re-read the comments policy. Pre-complaining about moderation is still a moderation complaint.

    This issue has been thoroughly addressed and you're not adding any new relevant material. The carbon you exhale comes from carbon in the current active carbon cycle. It's not adding any new carbon to the carbon cycle. 

    When we burn fossil fuels we are extracting ancient sequestered carbon from the earth's geology and, through combustion, are reintroducing that carbon to the modern carbon cycle.

    This is a very simple concept which is accepted across the board. For you to dispute it clearly puts you outside of any rational scientific debate. 

  46. +RH  It's nice to see the comment has not been removed on the basis that "it clearly puts you outside of any rational scientific debate".  Seems to me pretty close to argumentum ad hominem, but maybe that's just me.  Frankly I resent the implication that contradiction is "clearly" outside of anything.

    First, the level exhaled you led with was completely erroneous, and you did not dispute that, so you make your entire argument that the C was always there and we just recycle it, and disregard your first error.

    And I already answered that "recycle" argument.  The CO2 exhaled by all animals (and their number is growing, along with their exhalation) is in addition to the CO2 created by industry for any given year, and, while isotope analysis can identify that produced by burning fossil fuels (less and less distinctively as exhalation goes on), any warming effect claimed cannot discriminate between that which has increased due to industry and that which is exhaled by increased population of terrestrial animals.  

    Thus, it is not enough to conclude that the world's industry it causing anything (the idea of CO2's effect is not for this thread), while any official body (such as IPCC) simply dismisses it, and your counterargument seems to support such dismissal.  

    I put it to you that if your bank were to say that it paid 0.5% on your average current balance, and then excluded 30% of your balance because it was too recent, you would not bank with them any more.

    More significantly, imo, if any bank tried that, you would report them to the state banking commission.  IPCC is that bank, and their accounting is that faulty.

    RH, I'll ask you to keep the condescension down to a low roar.  I am a serious scientist.  I hope skeptical science has a few whose skepticism doubts the received wisdom of AGW alarmists and not somehow only that from "deniers".  Doubt is the basis for advancement in the sciences.  It should not preselect.  That's just prejudice, not skepticism.


    [JH] Sloaganeering and moderation complaint deleted.

    Please note that posting comments here at SkS is a privilege, not a right.  This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

    Please take the time to review the policy and ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter.

    [RH] Bill, while your original post was worthy of a complete deletion, it is sometimes instructive for other readers to leave such egregious examples where people think they know more than the entire rest of the global scientific community. That said, your tone and approach to this conversation are rapidly headed toward you being banned.

    We encourage open dialogue here at SkS with caveat that people stick to the science. Drop the aggressive rhetoric and you might have a productive learning experience here.

  47. DrBill, I watched the first half of your 30 minute Youtube presentation (from 2006).

    Frankly, the arguments put forward were appallingly poor.   So appallingly poor, that it woud be impossible for the second half of the talk to redeem the whole 30 minute venture and pull the fat out of the fire.   The arguments put forward were so fundamentally wrong in science, as to make your presentation a nonsense.   So much so, that it would be tiresome to enumerate & discuss all the errors.

    You said you presented your ideas to Science magazine — and were rejected (as being "not of general interest").    DrBill, the Science editors were being polite to you.   They should simply have posted your submission back to you, marked with a one-word red-pencil comment: "Nonsense".

    Your youtube video is a complete waste of viewers' time.

  48. Yes it is just you. "Ad hominem" means that an argument is attacked on the basis of the character  of the one who  makes it. An example would consist of saying that someone is a sleaze ball and therefore what they say is wrong or invalid. That is a logical fallacy, as the character of an individual has no bearing on the validity of the argument, which is to be judged on its own merit. I am surpised that a "serious scientist" could be confused on that point. If an argument is indeed removed from rational thought, it has no merit.

    As to the rest of the post above, I am not sure what you are trying to say. CO2 exhaled by animals is not, and can not be, a net addition to the carbon budget. The only way atmospheric carbon can see a net increase is by injecting some that was taken from an otherwise stable reservoir that kept it away from the atmosphere, such as the crust. Animals do not create CO2, nor do they have the possibility of fetching it in such reservoir, only humans have the power to do that. Furthermore, the majority of animals now existing on Earth are dmoestic animals, i.e. the result of human activity, many of them indeed the result of industrial agriculture. Industrial. 

  49. Dr Bill Hoffman @95:

    A)  You say:

    "As we breathe in 400 ppm CO2, we do not exhale "about ten times that amount", so the premise is incorrect. We exhale some 100 times that amount, about 40,000 ppm (4% CO2)."

    That is correct, but it is not a claim made in the Original Post.  Rather, it is an error by the AGW denier, "Ian Plimer" which was merely neglected as being trivial relative to the gross error rebutted in the OP, and which you appear to repeat.

    B)  You further say the IPCC is "...they focused entirely on industrial production...", but that is simply false as shown by the IPCC's summary diagram of the carbon cycle shown below:

    Note that the non industrial elements are determined by in-situ surveys, satellite observations, changes in isotope ratios, all of which are used to validate models.  For example, here is a paper analysing measurements of Dissolved Inorganic Carbon and comparing the result to earlier estimates.  And here is a review of data relating to anthropogenic emissions from LUC.  Your assertion in your video that "LUC" represents simply "a factor to allow adjusting" (8:44), ie, is merely used to balance the books is simply false.  At best it represents an overwhelming ignorance of the topic on which you chose to lecture.  The equation shown at that point in the video is also entirely of your own manufacture, so far as I can tell.  The IPCC TAR (2001), for example, shows the following elements in the carbon cycle:


    (For clear image of each panel, go here.)

    As the IPCC TAR was the report immediately preceding your presentation, your employment of a truncated equation of the carbon cycle that does not even include vulcanism shows you to be, at best, completely ignorant of what the IPCC claims.  Never-the-less, you feel qualified to make repeated false claims about what the IPCC purports to understand, and how they arrived at those conclusions.

    C)  Your model as shown on the video purports to show 100 Gt-CO2/yr (27.3 GtC/yr) emissions from respiration in 2004 (13:35).  You then show an estimate of the increase in CO2 emissions by animals of about 10 Gt-CO2/yr (2.7 GtC/yr) by 2004 relative to 1900(?) (14:36), which you claim (15:54) to be about 50% of anthropogenic industrial emissions.  Anthropogenic industrial emissions in 2004, however, were 7.78 GtC/yr.  Your "accelerated conversion" was, therefore, just over a third of industrial emissions, and less than a third of industrial emissions plus LUC.

    D)  Whether or not that represents a genuine increase in emissions depends on what you calculated, which is very far from clear.  To avoid excess length, I will discuss it in a following post. 

  50. Philippe Chantreau " I am not sure what you are trying to say. CO2 exhaled by animals is not, and can not be, a net addition to the carbon budget."

    No one said it was a net addition to the carbon budget.  And your clarification of what does add to the carbon budget actually helps identify my challenge to IPCC and their inadequate accounting/summarizing. [FWIW, the equation I showed, Tom, was directly copied from their 2005 Report that I used, and their dismissal of any CO2 but industrial has been shown multiple times in many forums, and informed my angry analysis.]

    In any given year, CO2 comes into the atmosphere from industry, transportation and respiration.  Its presence is all it takes to have any putative effect, not where it came from or what source.  If the atmosphere reacts to the presence of CO2, it does so without regard for its history.  The emphasis on its history is the bias in IPCCs conclusions.

    While I'm at it, Tom, your analysis of what I said does little to change my point, as expressed in the paragraph just above.  I said 40% more, and you want to argue 33%...tomayto tomahto...they found industrial CO2 and stopped accounting.  On the other detail (D), I used UN herd records for my animal calculations, added to it some lesser quality estimates of insect population (rounded down not to be too shocking), and worked with the same kind of growth curve you posted earlier in Fig 5.

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