Claim: plant respiration of CO2 into atmosphere underestimated by 30%

From the UNIVERSITY OF MINNESOTA and the “blame the plants not the humans for climate model failures” department.

Carbon emissions by plant respiration will have large impact on climate

Study finds that emission rates are 30 percent higher than previously predicted

New findings by researchers from the University of Minnesota College of Food, Agricultural and Natural Resource Sciences (CFANS), who partnered with scientists from across the world, suggest plant respiration is a larger source of carbon emissions than previously thought, and warn that as the world warms, this may reduce the ability of Earth’s land surface to absorb emissions due to fossil fuel burning.

The new findings, published in the journal Nature Communications, are based on the comprehensive GlobResp database, which is comprised of more than 10,000 measurements of carbon dioxide plant respiration from plant species around the globe. Merging this data with existing computer models of global land carbon cycling shows plant respiration has been a potentially underestimated source of carbon dioxide release. The study shows, carbon release by plant respiration may be around 30 percent higher than previously predicted.

As the mean global temperature increases, the researchers estimate respiration will increase significantly. Such increases may lower the future ability of global vegetation to offset carbon dioxide emissions caused by burning fossil fuels. CFANS Forest Resources Department Professor Peter Reich, Postdoctoral Associate Ethan Butler, Research Fellow Kirk Wythers and Research Associate Ming Chen teamed up with lead author, Chris Huntingford, of the United Kingdom’s Centre for Ecology & Hydrology, and 15 other physiologists and modelers in the work.

“Plants both capture carbon dioxide and then release it by respiration. Changes to either of these processes in response to climate change have profound implications for how much ecosystems soak up carbon dioxide emissions from burning fossil fuels,” said Huntingford.

“Once we incorporate this data into state-of-the-art carbon cycling models, we are much closer to being able to accurately model carbon cycle feedbacks for climates across the globe,” said Reich. “In fact, this study provides the most up-to-date accounting of respiratory carbon releases from plants in terrestrial systems.”

“The implications of this study are enormous,” Ming emphasized. “The fact that plant respiration is likely 30 percent higher than previous estimates should warn all global modelers that an updated inspection is warranted regarding how we model carbon flows in and out of terrestrial ecosystems globally.”


Paper details: Huntingford, C., Atkin, O.K., Martinez-de la Torre, A., Mercado, L.M., Heskel, M.A., Harper, A.B., Bloomfield, K.J., O’Sullivan, O.S., Reich, P.B., Wythers, K.R., Butler, E.E., Chen, M., Griffin, K.L., Meir, P., Tjoelker, M.G., Turnbull, M.H., Sitch, S., Wiltshire, A. and Malhi, Y. (2017) Implications of improved representations of plant respiration in a changing climate. Nature Communications. DOI: (open access)


Land-atmosphere exchanges influence atmospheric CO2. Emphasis has been on describing photosynthetic CO2 uptake, but less on respiration losses. New global datasets describe upper canopy dark respiration (Rd) and temperature dependencies. This allows characterisation of baseline Rd, instantaneous temperature responses and longer-term thermal acclimation effects. Here we show the global implications of these parameterisations with a global gridded land model. This model aggregates Rd to whole-plant respiration Rp, driven with meteorological forcings spanning uncertainty across climate change models. For pre-industrial estimates, new baseline Rd increases Rp and especially in the tropics. Compared to new baseline, revised instantaneous response decreases Rp for mid-latitudes, while acclimation lowers this for the tropics with increases elsewhere. Under global warming, new Rdestimates amplify modelled respiration increases, although partially lowered by acclimation. Future measurements will refine how Rdaggregates to whole-plant respiration. Our analysis suggests Rp could be around 30% higher than existing estimates.


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“this may reduce the ability of Earth’s land surface to absorb emissions due to fossil fuel burning.”…

oh noes……run away global warming

Do these people know that CO2 levels drop?


…and that temps drop no matter what Co2 is?

the other Ed Brown

We’re doomed!


This sort of finding really drives home how ridiculous ‘the science is settled’ claims really are. They haven’t even got the plant CO2 calculations right! How the hell do they know what the future holds if multitudes of other factors have to be considered? Global warming? That expression ‘it’s the sun, stupid’ makes sense to me.

“this may reduce the ability of Earth’s land surface to absorb emissions due to fossil fuel burning.”…

Doesn’t this also make the control of mankind’s carbon emissions less meaningful.


Do you think these bozos have ever done a mass balance on this? What percentage of the absorbed CO2 is retained in the plants? And increased CO2 increases growth, retaining even more CO2. This is a big load of bull dust.


Never mind that oceans utterly swamp the ’emissions’ or absorption of CO2 from vegetables.

Not really. Land vegetation has about twice the atmospheric exchange as the oceans.

Samuel C Cogar

Land vegetation has about twice the atmospheric (CO2) exchange as the oceans.

“YUP”, ….. shur nuff, gymnosperm, ….. youse just gotta be correct about that cause everyone knows that bout 70% of the earth’s surface is covered with green-growing, CO2 exhaling, “land vegetation” and only bout 30% of the earth’s surface is covered with ocean water.

Samuel C Cogar

Much obliged.


“The implications of this study are enormous,” = Send more money.

…says one of the authors. I’m still waiting for the author that says his work doesn’t really tell us very much.


A number of years ago the astrophysicists were saying precisely that. They were saying that the sun didn’t have much impact on the climate but solar physics was interesting in and of itself and should be funded.
Not kidding.
Talk about a climate of fear.

30% higher than WHAT? 30% larger than a small number is still a small number. Jeeez!!!


Plant respiration is a big number.


well sorta considering we’ve been measuring it for a few decades ;)……it don’t matter


Plant photosynthesis is a bigger number. Plants grow, they don’t shrink. This would only “be worse than we thought” if respiration increases faster with temperature than photosynthesis, and we know that the opposite is true. Plants grow faster in summer than in winter.


It really is a big number. The IPCC estimates, and NOAA agrees, that humans account for 3% of the influx of CO2 into the atmosphere. The rest is natural. If the estimates of CO2 from plants was 30% low, then the human contribution shrinks accordingly.
I have made this statement a number of times on blog sites of various sorts. I think that 3% number just puts to rest any hysteria about fossil fuel burning and CO2 in the atmosphere. Surprisingly, nobody seems to think that number matters much.

Joel, I think it matters a lot–the 3% number. There are a few really significant numbers that skeptics keep accepting when we engage in AGW conversations that really puzzle me. This includes the bogus ongoing historical temp adjustments and the fact that the earth did fine at 4000 parts per million CO2–it’s like we try to be rational using their irrational and non-factual premises. If we account for only “3% of the influx of CO2 into the atmosphere,” that is a big number.


I would guess that uptake of co2 by plants is very close to equal to co2 respiration plus decay. My evidence:


Nahh…..We’re listening mate.


rh, there is now much less air space than when it was a single leaf seedling.


Andy, There might be a lot less space than when it was a seedling, but I bet the airspace hasn’t changed much in the last 30 to 39 years.


Joel, I have often heard that 3% number, and you are right – it is a very important number. Can you point me to the IPCC estimates, and NOAA agreement? Thanks.

Samuel C Cogar

So askith: arthur4563 – November 18, 2017 at 2:08 pm

30% higher than WHAT?

“Previous estimates”, that’s WHAT, …… nothing more, …… because it was “nothing more” than a CYA, ……. to wit:

“The fact that plant respiration is likely 30 percent higher than previous estimates should warn all global modelers that an updated inspection is warranted regarding how we model carbon flows in and out of terrestrial ecosystems globally.”

T’is/t’was nothing more than a touted CYA in a feeble attempt to explain why atmospheric CO2 ppm has continued to INCREASE …….. even though global average temperatures HAVE NOT BEEN increasing.

The New York Times – Aug 21, 2013 @ 05:58 PM

Dismissing the recent 17 years or so of flat global temperatures, the IPCC will assert that: “It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010.

“DUH”, first it was the “missing” heat they were looking for, …… now they have found the CO2 that they didn’t know was “missing”.

Moderately Cross of East Anglia

Oh well, at least the science is finally settled. Oh wait….


Oh wait …

Nailed it!

(if I was feeling a bit, you know, Snarky, I could, I suppose, change my handle to

‘The science is so really, reelly settled, honest Guv, God’s truth, on my baby’s life! Again!’

But that is what about one third of the contributors here are saying, over and over again, so I should not take the credit from better minds than mine.)


do they have babies, to swear upon? i don’t believe it

As usual they are obsessed with modeling and want to support the IPCC claim that global warming will cause carbon sinks to absorb less CO2. I have a primer on Carbon Fluxes, Sources and Sinks with links to observations and recent research.


Some remarks on your work:
It goes already wrong in the first diagram from Segalstad:
If you add a lot of CO2 to a CO2 cycle in dynamic equilibrium, whatever the size of the cycle, that will increase the levels in the atmosphere. Thus the graph of the additions should start at 400 GtC level. How fast that increases in the atmosphere is a matter of decay rate for any injection of CO2 in the atmosphere (volcanoes, humans,…) above steady state. The observed e-fold decay rate is about 51 years, or a half life of ~35 years, no slowdown in sight. Thus the IPCC’s 1000’s of years for a part of our CO2 is only based on a (probably) faulty model (the Bern model)…

This generates a gap of 20 Pg C between the global emissions and absorptions

Can’t be right: what is measured is an increase of about 4.5 GtC/year with about 9 GtC/year of human emissions. That is far more accurate than subtracting two huge estimates…

Then the ever returning fundamental error by Segalstad and too many sceptics:
The turnover of CO2, or residence time, has nothing to do with the time needed to remove an extra shot CO2 out of the atmosphere. It is the same error as confusing the turnover of goods and thus capital within a factory with the gain (or loss) of the same factory at the end of a fiscal year…

For a comprehensive overview why humans are to blame for the CO2 increase in the atmosphere:
Which doesn’t imply that the increase has a huge influence on temperature…


Ferdinand, I’ve said this before and say again, you are communicating well and I value your comments when people mix half-life and residence time.

Pamela Gray

Do you factor in the amount of increased greening that has fairly steadly occured since the little ice age? A warmer wetter world will result in fairly steady increased greening. Regardless of what humans do. It will continue until we are a lush green land interspersed with wide expanses of ocean blue. Even Greenland will once again be green and capable of sustainable farming as it once was. The only thing that will stop it is for the oceans to go into net absorption mode.

Thanks for the comment Ferdinand, and for the link explaining your understanding. I know from reading many threads over the years that you are firm in your position and can defend it against any and all comers.

I can only say I do not share two assumptions that underlie your support of IPCC conclusion re. all CO2 increase comes from humans. IMO the isotopes do not prove what you say because the ocean interchanges them indiscriminately and because decomposing modern vegetation produces the same as burning ancient vegetation. I also think the stomata research shows much more natural variability contradicting the notion of a steady state carbon cycle prior to fossil fuels. The correlation between rising CO2 and rising FF emissions is positive, but so do SST changes correlate with rate of CO2 change. I can’t prove you wrong, and will not try, but I do not share your assumptions and thus your conclusions.


The deep oceans are the main reservoir which was in steady state (dynamic equilibrium) with the atmosphere, depending of the temperature of the ocean surface in the pre-industrial period. If there is a disequilibrium like for the ~115 ppmv extra CO2 pressure of the moment, more CO2 will be absorbed.
The same is true for the extra CO2 uptake by plants: more CO2 pressure increases plant growth.
Despite these two extra sinks for CO2, the extra plant growth and removal of CO2 into the deep oceans is not enough to remove all human contribution in the same year as emitted. Therefore CO2 levels still are climbing in the atmosphere.
The current understanding (based on isotopes, oxygen use, partly direct measurements), is that the extra sinks are about 50-50 between oceans and land, but that the net land uptake is less, because humans (still) clear more land than is reforested.
Both net sinks remove about half human emissions each year, but the year by year variability of the sinks is highly dependable of the surface temperature (El Niño, Pinatubo)…


Except for a small contribution by the past temperature increase (~16 ppmv/K over the past 800,000 years), most increase of CO2 indeed is from fossil fuel burning.
There are only two known sources of huge quantities of low-13C: recent organics and fossil organics (with a possible exception of non-bio methane). All the other sources: oceans, volcanoes, carbonate rock weathering,… all have (much) higher 13C levels.

The natural variability of the δ13C levels in the atmosphere only changed a few tenths of a per mil even over huge changes like glacial-interglacial warming and back. Since we have burned a lot of FF, the δ13C levels in the atmosphere dropped with over 1.6 per mil, not seen in many millions of years…
Further, while plant respiration and decay gives CO2 with about the same per mil as fossil fuel, plant uptake does the reverse. As there is currently more CO2 uptake by plants than release (based on the oxygen balance), the whole biosphere removes relatively more 12C than 13C, thus is not the cause of the 13C decline…

Then the stomata data: that are proxy data from leaves that grow by definition on land, where current CO2 levels change from 250 to 550 ppmv within a day… These are calibrated against… ice core data, which are the gold standard. The only advantage is a better resolution, but not a good indication of real “background” data in absolute figures.

SST changes precede CO2 rate of change changes, but that is only the +/- 1.5 ppmv noise around the 90 ppmv trend in the past 60 years…


“If you add a lot of CO2 to a CO2 cycle in dynamic equilibrium, whatever the size of the cycle, that will increase the levels in the atmosphere.”

By the same proportionate amount as its proportion of the inputs. You cannot impose separate dynamics on the portion that maintains equilibrium, versus on any addition. This is your fundamental error.


The natural input and output fluxes are near completely temperature driven (+/- 150 GtC/year).
The (un)balance between inputs and outputs is near completely atmospheric CO2 pressure driven (- 4.5 GtC/year)
The human input changes the CO2 pressure in the atmosphere, independent of temperature.

The removal of any extra CO2 mass above steady state is largely independent of the size of the natural CO2 cycle…


If there was a substantial change in the natural seasonal CO2 cycle, it may have played a role in the CO2 increase. Here I have compared the seasonal cycle at Mauna Loa averaged over 1959-1976 and 1994-2013:

While there is little change in amplitude of the seasonal cycle (thus the main in/out fluxes), the residual increase of CO2 after a full cycle increased about a threefold, that is the same as what human emissions did between the two periods and what the driving force did for the extra sinks: the extra CO2 pressure in the atmosphere above steady state.
Human emissions were about twice the net increase over the two periods…

Ian W

@ Ferdinand Engelbeen November 20, 2017

You are making the assumption that the sink of CO2 is constant and only governed by laws such as Henry’s law. You ignore the possibility of a non-linear growth in the sink caused by the biosphere for example an ocean algal bloom or sudden increase in ocean foraminifera. Indeed, this could already be happening but as your arguments are circular inventing a capital loss (?) you cannot see it. The CO2 currently in the atmosphere is the difference between the source output and the sink absorption; that is what is shown by the annual change graphs with one following the other. The anthropogenic input to this is extremely small compared to that of natural sources but as the sink lags the source (as you would expect) by a similar but larger amount you assume that it follows that anthropogenic sources must be the reason for the small imbalance. That is correlation not indication of causation – that gap between source and sink will always be there with rising CO2. Remember CO2 has risen (and fallen) before there were anthropogenic sources for you to ‘blame’ for the changes.

It seems that one climate organisation doesn’t (want to) know what another has already found…

Of course, if there is no balance between uptake and respiration by plants, either more CO2 is released or more CO2 is absorbed… Both from the oxygen balance as from satellites looking for chlorophyll: the earth is greening, thus more CO2 is absorbed than released by all world plants.

All what the researchers have found is that the respiration part (estimated at about 60 GtC/year) was underestimated with 30%, thus now is estimated at 80 GtC/year. The net result is that the uptake also is underestimated with 20 GtC/year and now is around 81 GtC/year (besides a seasonal cycle of ~60 GtC within a full year)… It is the net result which is measured…

Short term warming in the tropics (El Niño) gives a net loss of CO2 from the (too) warm and dry tropical forests. Within 1-3 years that is fully restored and a mature forest is rather CO2-neutral.
Longer term warming gives that extra-tropical forests and (semi)deserts only get greener. Forests were growing up to the Arctic Ocean in Alaska during the warmer Eemian (110,000 years ago), where now only tundra grows…


Thanks for once again providing needed context.


Absolutely. This is a simple thing but muddled by authors for some reason.


If I wasn’t busy, I would have said all that first. 🙂

Yes, the carbon in the active carbon cycle has increased,to the benefit of ALL life on Earth.

And I hope that human emissions of CO2 are at least partly responsible,
because that would mean the amount of carbon in the active carbon cycle would continue to increase.

“It seems that one climate organisation doesn’t (want to) know what another has already found”

I don’t think there are climate organisations involved here. But you’re right that it isn’t a new net source of carbon. Whatever plants respire can only be what they have previously photosynthesized. They could suggest the magnitude of the cycle is larger.

Contra the article, there is no “climate model failure” involved. Climate models work from gas concentrations. They may attach a carbon cycle model, but that would be consistent with the observed annual CO2 cycle. All that is really happening is that of the photosynthetically reduced carbon returning to air, a component formerly attributed to decay is now attributed to respiration.


“a component formerly attributed to decay is now attributed to respiration.”

So, no decay any more, hey Nick.

You are getting very confused, aren’t you. 🙂


On any given day, my admiration for your scientific input veers from the credulous, to the incredulous.


“Forests were growing up to the Arctic Ocean in Alaska during the warmer Eemian (110,000 years ago), where now only tundra grows…”

Not only there, also in Siberia. And most of Sahara was savannah.

Crispin in Waterloo

I would put it in a shorter form:

If the respiration out is 30 Gt more that expected, the uptake is also underestimated by 30 Gt because we know what the net uptake is. Because of an increase in the available CO2, there is an increase in the net uptake. That’s the important bit.

So what if 60 is taken up and 30 given back, or 90 taken up and 60 given back? What value is there in knowing more precisely the size of the ‘given back’ portion? This changes nothing for the climate. It may be of interest to plant biologists and it is hard to believe this is something they were unaware of. People have been studying plant respiration for a very long time.

Cotton plants take in CO2 and sunlight all day, but increase their stem diameters at night! While that is happening, they give off CO2. Who knew? Quite a number of people, apparently. It is part of plant physiology.

The paper has too much verbal mush trying to sell the idea that as atmospheric CO2 rises in concentration, plants will emit more which will make the concentration rise faster. Faster than it would without plants? It is well established that at higher concentrations of CO2, plants take up more of it at a faster rate using less water per kg of gain. Twisting that into ‘faster growing plants will make the CO2 rise even faster’ is silly. They can’t give it out if they didn’t already take it in. Any increase in the total biomass reserve subtracts CO2 from the atmosphere.

Mike Jonas

Thanks, Crispin. Just what I was going to point out. But I’ll add my bit anyway so that you’ve got company: We know from satellite studies that global flora has increased significantly (in spite of increased land clearing). So we know there has been a net carbon uptake. End of story.

“So what if 60 is taken up and 30 given back, or 90 taken up and 60 given back? What value is there in knowing more precisely the size of the ‘given back’ portion? This changes nothing for the climate. “
I agree. Although I think the discrepancy is probably partly more photosynthesis, part less bacterial respiration. But little significance for climate.


“But little significance for climate.”

Its CO2, Nick, so basically ZERO significance for climate.

Nick, we are not talking about bacterial respiration in soil (or wherever). We are talking about plant respiration. Folks have this notion that plants do photosynthesis out of philanthropy. Not at all. They are gnarly just like us and burn baby burn to create their biomass.

“burn baby burn to create their biomass”
They unburn to create their biomass. But the reduced carbon they produce can’t last in an oxidising atmosphere. The argument in this paper is just about who gets to it first – the plants themselves respiring, bacteria and fungi in dead wood and soil, fire. They want to up the plant respiring portion, maybe increasing the total in the cycle. OK.

The net isotopic effect to the atmosphere of plant respiration is about -4 PDB. Plants filter for 12C both in and out, with photosynthesis being far more discriminating than respiration. Plant respiration cannot absolve humans. The negative contribution is way too low, but a 30% underestimation pushes the right way to help balance the Isotope Integrated Carbon Cycle.

It is not enough. The isotope integrated cycle still does not balance. There other problems to be resolved.


I see. But the authors claimed this is enormous, significant change.


Nothing balance. It justs tend to balance.

Very true, but after millions of years, you want the imbalance to be reasonable. It is so far off one suspects a missing piece to the puzzle.

I would have said the vegetation cycle previously was 120 GTs per year.

– photosynthesis/growth absorption -123 GTs;
– winter die-back release – 60 GTs;
– release from vegetation-covered soils – 60 GTs.

Net absorption 2 to 4 GTs Carbon per year, lower in warmer El Niño years, higher in cooler years.

There were other studies recently that used data from the forest carbon and grass carbon projects that said the number had to be higher in the 150 GTs range. These are all well-designed in-depth projects that go on for years. They literally have towers and monitoring stations over a large area and can be very accurate about what’s going on.

Because of these studies, I have been using 150 GTs per year for quite awhile now.


– 150 GTs in;
– 146 to 148 GTs out depending on the temperature that year.


– 92 GTs in;
– 90 GTs out.

Pamela Gray

If more of the Earth is greening, then more insects are thriving. Seasonal release of carbon should also increase in the decay cycle as well as the increased exhaled CO2 from insect increase. Result: An increasing green Earth will show increasing CO2. Until the long term weather patterns turn nasty.

Samuel C Cogar

Ferdinand Engelbeen – November 18, 2017 at 2:23 pm

Forests were growing up to the Arctic Ocean in Alaska during the warmer Eemian (110,000 years ago), where now only tundra grows…

Ferdinand, were those boreal forest also growing up to the Arctic Ocean in Alaska during the late Holocene period, 9,000 years ago, when they were growing up to the Arctic Ocean in northern Russia and Siberia?

And if not, ……. why not?

Radiocarbon-dated macrofossils are used to document Holocene treeline history across northern Russia (including Siberia). Boreal forest development in this region commenced by 10,000 yr B.P. Over most of Russia, forest advanced to or near the current arctic coastline between 9000 and 7000 yr B.P. and retreated to its present position by between 4000 and 3000 yr B.P.

Read more @


I was aware of the forests in Alaska up to the Arctic Ocean during the Eemian (5-10 C higher temperatures than today!) but there may be more recent periods where the forests advanced as much during the first warm period in the current Holocene. I hadn’t seen that for Siberia (Yamal?) and Northern Canada, but it seems obvious that temperature will have a huge effect on the northern treeline…

Larry Vaughn

When did Science become, “Make up your own science and facts?” I read the posts and I am constantly amazed at some of the crap that “Scientist” publish and expect us to believe. I understand how the average folk take and run with some of this but really, It’s just sad the state of our science education.{I am a retired science teacher}

Sceptical lefty

If you really want ‘hard’ science, based on strict empiricism, repeatability, etc. you are pretty much restricted to physics, chemistry and associated disciplines. This is the ‘high (but not perfect) integrity’ stuff.
Everything else has data gaps, questionable (or nonexistent) repeatability and plenty of room for speculation. These fields are dominated by ‘authorities’ or ‘doyens’ who effectively determine what is ‘in’ and what is ‘out’.
It has been like this for a long time.


indeed. And so it must be. People must know that even medecine is not “science”, except very basic layer


“As the mean global temperature increases, the researchers estimate respiration will increase significantly.

What increase?


More properly, that should be IF the mean global temperature increases.


Posted too soon. Every week, there’s new “more than we thought” articles, which might make a sensible person wonder just how much the DO know. More CO2 from natural sources means all previous estimates are wrong, as far as CO2 in atmosphere, etc., how long it persists, and so on.

I remain certain that the “worst damage” and the “first changes” will continue to be near the poles, where it’s very difficult for people to go see for themselves.

Robert from oz

Free energy for plants ?

Tom Halla

We should ignore this study as the models are established science./sarc


Sorry. That didn’t work.

Samuel C Cogar

Gabro, here ya go, …….. for posting a “hyper-link”, …..

URL hyperlink: word(s) to link

Samuel C Cogar

OOPS, tried to fake it out but no succeed.

Try this one, but replace the 2 capital “Z” with 2 small “a”‘

URL hyperlink: word(s) to link

Samuel C Cogar

HA, ….. forget my attempts and read the FAQ for this site.


Gabro, use angle brackets not square, or even easier just post tge bare url.

Gunga Din

So now green things are the cause? It’s now CGGW? To “go green” we must now destroy green?


“profound implications for how much ecosystems soak up carbon dioxide (ummmm…..FROM THEIR OWN CREATION) emissions from burning fossil fuels”
Seems plants don’t absorb their own CO2 – you know, the very food that gives them life….but rather, only fossil fuel origin CO2…..
I didn’t know the carbon cycle was so tricky.

And, the increase on the TOTAL CO2 in the atmosphere since the start of the industrial age, is how much?
Then, if the naughty plants themselves were a contributor to this increase – a significant contributor, then they need to be removed, or taxed…or both.

Hmmm…I think a model will need to be created to sort this issue out.

Steve Case

It’s sort of like the complaint from the left that the rich get the biggest tax break. Well yes if the rich pay the most taxes then when there’s an across the board tax cut they will get the biggest cut. Same with green plants enjoying an increase in primary production due to increased CO2. Then the amount of CO2 emitted from their respiration will increase in proportion. It’s really a dumb argument. Ten percent of the bigger number is more than ten percent of the small one. Right in there with pointing out that tall people wear bigger shoes and eat more.

Frederik Michiels

So as the models were already completely wrong, it would mean that if they would have taken that 30% extra CO2 in account they would have been more wrong?

just wondering…


I think ‘not more wrong, proportionally’ . . .


The plants, unlike many Climate Scientists, know what they are doing.


It is more like 3%, according to the IPCC.

Joel November 18, 2017 at 3:25 pm:

Yes, Joel this 3% is an often repeated figure…even Ian Plimer has used it but I’ve never found the money quote from IPCC reports or NOAA as you mention upthread.

Would you have a reference to either or both of them as it would be a useful figure to have up one’s sleeve at times. I’m also unsure if the 3% refers to just the manmade proportion of the total atmospheric CO2 and/or the amount added each year or what…I’m confused (but that’s entirely normal for me!).

The 3% is from many years ago, currently the natural cycle is about 150 GtC/season in and out (*), in large part countercurrent between oceans and vegetation. Human emissions at about 9 GtC/year (only FF burning, deforestation excluded) are about 6% of the natural cycles in quantity.

In fact not important at all: even if it was 0.6% or 60%, human emissions are one-way additions, not part of the natural cycles, which are near entirely temperature driven. Any extra CO2 pressure in the atmosphere has little effect on the amounts going in and out over the seasons…
Of course, when the CO2 pressure in the atmosphere increases, that will reduce the CO2 input from the upwelling zones near the equator and push more CO2 into the sinking waters near the poles (the same for the uptake by plants). That is a CO2 pressure driven process, which is much slower than what drives the seasonal exchanges.

Seasonal: ~5 ppmv/K globally, response time: months
Pressure: ~2.15 ppmv/110 ppmv extra pressure in the atmosphere, e-fold response time: ~51 years.

(*) The amounts mentioned in the article are part of the diurnal cycle (250 ppmv during the day – 550 ppmv at night under inversion) within vegetation, which hardly reaches the bulk of the atmosphere and is not measured at most monitoring stations, as these are away from vegetation and mostly measure already mixed “background” CO2 levels.


So the models are even wider off!


Now come on. Plants are net absorbers of CO2. This must be the case or animals, which absorb O2 and emit CO2, would soon run out of O2 and we’d suffocate from CO2.

Therefore, if plants are respiring more, they must be photosynthesing more to create the food in order to respire. That equates to a net reduction of CO2 by plants, not a net increase.

To me, that seems to negate the entire premise of the study, at least judging by the title. I did read the press release and it didn’t disprove my argument.

“That equates to a net reduction of CO2 by plants, not a net increase.”
It could be a net reduction, but it’s still an increase in respiration. It all has to be balanced somehow. It probbaly means more expired by plants, less by microorganisms. Neither can be measured directly, globally.


And why would an increase in respiration matter in any way, Nick?

If plants use the same amount of CO2, they are just getting more efficient. If they use more CO2, then there is not net effect.

Why should we care?

“Why should we care?”
Dunno. It’s just jiggling poorly known components to fit a better known balance.


“It’s just jiggling poorly known components to fit a better known balance.”

Like climate models, except that the balance isn’t known, its pre-supposed by an agenda..


Well, reading that is hard work. Some points:

… except in the tropics where acclimation to higher temperatures lowers respiration.

That observation right there effectively states that any increase in respiration due to temperature increases would quickly reduce again once plants acclimatise.

I’m also quite confused as to what empirical data is used, if any. They seem to pick ‘real world’ locations and then get ‘data’ from models based on those locations.

They appear to have taken data from actual studies, but then they model them while making assumptions about the canopy in some way. I can’t follow that to see how that is transferred from the data which have no such reference, except maybe the lighting when measurements were made.

In any case, if plants respire more given the same amount of photosynthesis (or CO2 absorbed, essentially the same thing) then that can only mean that they are getting more efficient. So now we are supposed to be scared because plants are going to get better at being plants? If they are actually photosynthesing more, the net effect is more O2 and less CO2, which destroys their argument.

Overall there’s a major reliance on models (as usual) and seemingly dubious arguments to support their theories as opposed to findings leading to a theory. How hard is it to actually just design some simple controlled experiments with varying temperatures and CO2? What is happening to science when the simplest of experiments (as could be employed here) are replaced with models that just produce what they are programmed to produce?

Gary Pearse.

Look, I’m not a plant physiologist but this is pure bunk. BTW, 30% of how much? Here’s what we know for the benefit of our aggie friends. 1) Forest cover has expanded its coverage of the globe by 14% and trees already here before have gotten fatter. This extra mass is is a big reduction from what was added by fossil fuels to the atmosphere. A ten year old tree has~250kg of carbon on average. Googling the number of trees on the planet gives an estimate of 3 trillion, 14% of which are new trees, let’s say 500Bt. Now subtract the 30%of the small amount of carbon dioxide they exhale. 2) It just so happens we have a continuous record of CO2 growth in the atmosphere and your accountant could tell you that the gross number already includes your anxiety.

I hope this has been helpful.

Gary Pearse.

Oh and hey, I left out all the other plants that are devouring and the Sahel, Ozzie Outback and assorted other arid regions of the earth and even everywhere else. Even maple syrup is surging, and you aggies must know crop harvests have doubled. Com’on.


If only they would also devour the rabbits and cane toads, and maybe foxes, we’d be laughing!

“That is an interesting perspective on the sources of atmospheric CO2 levels.”
It’s an old nonsense. Plants absorb about 100 Gtons/year in photosynthetic reduction. Almost all gets oxidised again. Some by plant respiration, some by decay, which really means respiration of microorganisms. Some by fire, and some by respiration of higher organisms, including us. It’s the same carbon, cycling. This paper shifts a block of oxidation flux from other columns to the plant respiration column.


And the oceans remain entirely inconsequential in your calculation.

“Mark Steyn did not make the comment you noted, Rand Simberg did.”
I didn’t say he did. Simberg was a defendant too.

“The issue I raised was the SOURCE of CO2 in the atmosphere.”
And plants are not a source. They borrow C from the atmosphere, and return it.


Nick, “And plants are not a source. They borrow C from the atmosphere, and return it.”
What? No sequestration?

No. It did not shift the column. It grincreased the mass of the cycle. Our conception of the Carbon cycle is way too primitive to be insisting on a total mass.

Rhoda Klapp

That cow belch thing that some folks get excited about is part of the same cycle. The cow isn’t making the CO2 or CH4, merely channeling vegetation.

Pamela Gray

Nick, your comment makes sense. I would add that a warm wet environment will cause plants, micro/macro respiring organism, and land animals (including us) to increase, thus increasing exhaled CO2. It is a warm wet planet, at the mercy of an obliging ocean, that has gotten us here. The switch is in the oceans.

Forrest Gardener,

The point often overlooked by skeptics is counting only the natural sources and forgetting the natural sinks…

There are huge cycles at work in nature, where vegetation is the dominant cycle. That is the day/night cycle (~80 GtC in and out), where this article is about and the seasonal cycle (~60 GtC in and out). The oceans have their own -opposite- cycle for temperature of about 50 GtC out and in. Net effect over the seasons: about 10 GtC in and out, mainly in the more forested NH.

Human emissions are one-way additional, not part of any cycle.
What matters is not how large human emissions are compared to any (part of the) natural cycles, but how large human emissions are compared to the endresult of all full natural cycles: that is about half human emissions each year. Thus humans are responsible for most of the increase, no matter that the natural inputs are 10, or 100 or 1000 times larger…


“What matters is not how large human emissions are compared to any (part of the) natural cycles, but how large human emissions are compared to the endresult of all full natural cycles: that is about half human emissions each year.”

Incorrect. Once released, human emissions join the flows of the natural cycles. They are carried away by the sinks proportionately. As a result, they can only increase the ambient level in their proportion to the natural flows.


They are carried away by the sinks proportionately. As a result, they can only increase the ambient level in their proportion to the natural flows.

That would be the case if there was one CO2 cycle involved and the natural 150 GtC was flowing in total in and out over the seasons. That would give maximum 6% human contribution in the atmosphere after many years.
In reality, some 50 GtC is flowing out the ocean surface in warm seasons and absorbed again in cold seasons. The opposite happens in vegetation: 60 GtC is absorbed in warm seasons and released again in cold seasons.
Net effect: a global amplitude of 10 GtC (5 ppmv) over the seasons, mainly in the NH.

Balance: 9 GtC from humans within a net natural cycle of 10 GtC, or about 47% is the maximum human ratio in the atmosphere.
The measured % human CO2 in the atmosphere is already around 9% and increasing…

Moreover, the natural CO2 cycles replace about 20% of all CO2 in the atmosphere. That is simple redistribution between reservoirs, including the changing 13C/12C ratio. That makes that the 13C/12C ratio decline is only 1/3 of the decline if all human CO2 still would be in the atmosphere.
The net removal of any extra CO2, as mass, above steady state is a different matter and much smaller, nowadays about 4.5 GtC/year, by coincidence about 50% of the human contribution.

Based on all available evidence, humans are responsible for most of the CO2 increase…


@Nick Stokes
“Plants absorb about 100 Gtons/year in photosynthetic reduction.”
But this CHANGES. Without human input it could be about about 90 Gtons, and if human input grows, it will be about 110 Gtons

“Almost all gets oxidised again. ” then, again, when will it be? january of next year, or a century or even milions of year later, when some specie or some volcanoe send it back in the atmosphere?
Actually, most of what humans send in the atmosphere last couple of century, and that plants reduced, hasn’t started to get oxidised back yet: the rate of increase of atmopheric CO2 is still lower that our input.


methink you should stop making CO2 balance, and start making heat and energy balances. Heat reservoirs, heat transfert, enthalpy, etc. This as much a thing you are proficient at, and much more relevant since we are supposed to be talking about “warming” (for whatever it means).
Does CO2 change lapse rate of atmophere? Does it change insulating property of atmosphere? at sunny day? cloudy day? clear night? cloudy night? in summer?, in winter?
CAGW theory is litterally a flat-Earth, no cycle (day/season) theory, based upon yearly averages.


Thanks for the offer, but that part of physics is too long ago for me (and still have another life besides discussions on the Net…). Except for a sporadic encounter with the sky dragons, where they make similar mistakes in balances than some here about chemistry, solubility and mass…

paqyfelyc commented – “methink you should stop making CO2 balance”

there *is* a
carbon cycle, & it
does balance.

Does that also mean that through the process of photosynthesis that 30% more oxygen is at the same time being put into the atmosphere from these plants through their respiration process?


No. Respiration uses oxygen and produces CO2.

Plants use CO2 and sunlight and water to produce food and oxygen. They then ‘burn’ that food like animals do to use that stored energy.

If they really do respire more when it gets warmer, either they use more CO2 (most likely) and the net effect is zero, or they are just getting more efficient. Either way, there’s no need to worry.

Photosynthesis converts CO2 into O2. Respiration puts absorbed moisture through the plants process back into the atmosphere. It’s water. Clear processed water!
This whole process is in God’s control, and we can’t even try to mess it up.
It is a perfect engineering plant process.


Sorry I misread your comment.

I would have said ‘yes, probably’ if I’d read it properly.

M Seward

This sort of crap is about the same as putting a zoom lens on an ant and shouting to the world that ants have HUGE TORSOES relative to their total body mass, INCREDIBLY STRONG LEGS capable of independent movement and MASSIVE JAWS that can cut another ant in half. Furthemore IF THE MODELS ARE CORRECT and CO2 causes ants to grow to the body mass of even a dog or a cat they will easily CONQUER THE PLANET.

In other words its tabloid style science COMMUNICATION, aka baseless drivel serving as propaganda.

Its the sort if vacuous crap that is de rigeur in North Korea.

Well done ‘climate science’ you have found your nirvana.

Bruce Cobb

Oh good, another positive feedback mechanism. How many have they got now? By their accounting, the world should have already fried by now.

M Seward

Well Bruce certainly the more vulnerable brains are frying. Poor old Nick Stokes is sizzling!


Interesting: dark respiration (Rd), I first I thought they were aligning dark respiration with dark energy / dark matter so a quick trip back to the 1970’s found the increase of C02 around the leaves during darkness indicated the sequestering of CO2 was not happening without light….. 🙂


“Enormous implications” Really?

They imply that the models assume plants are storing 30% more carbons compounds than reality. If the fabulous GCMs assume that, How many other ridiculous assumptions are there? Many surely.

” If the fabulous GCMs assume that”
They don’t.


the whole photosynthesis process use up HUNDREDS OF WATTS (tens for the synthesis part, and much more for the water cycle part). A single 1% of this process is more important that the so-called “GHG forcing”. 30% unknown is just staggering
If “they don’t”, they obviously have are crap.
And if they did, with wrong numbers, so they are, too.
Either way they are crap.

michael hart

It’s another great example of inability to join two dots.

That they are so wrong with number (and there is no reason to believe they are correct now) doesn’t even give them pause for thought that maybe their other estimates might be wrong too. It must always be worse than we thought, never better than we thought.


To clarify a factor which may be undefined in some minds I will add the following. Plants do not put out CO2 (“respiration”) in a ratio matching 1:1 what take in performing photosynthesis.

For variation among even members of a kind of plant & how that ratio alters over the course of a year see Figure 1 & 2 of Gratani et al. (2007) “Relationship between net photosynthesis and leaf respiration in Mediterranean evergreen species”; free full text available on-line. Incidentally, the reports 1st paragraph mentions prior published research predicting 35% under-estimation of plant respiration (I haven’t cross referenced to see if any researchers cited by Gratani in 2007 were also involved in the original post above).


Edit: – last sentence delete word “under” , insert “CO2 loss”.


OCO-2 data backs this up. Tropical forests (Amazon, Congo) are sources not sinks. Reversal of paradigms.
Points toward temperate NH forests and the ocean phytoplankton as the true biological sinks.


This also explains why the Biosphere-2 experiment had such a huge CO2 build-up problems.
Not enough ocean.


According to these authors plant respiration is significant but they don’t know how significant..

These authors said that plants respire more but grow faster with higher levels of CO2

This lot think that everyone else has underestimated CO2 uptake by plants

Now these chaps think that land plants respire 11 times as much CO2 as produced by humans
[naughty plants]

And then if we’ve got more CO2 in the atmosphere the percentage of oxygen might increase [a good thing?]

The science is settled ?

“Plants both capture carbon dioxide and then release it by respiration. Changes to either of these processes in response to climate change have profound implications for how much ecosystems soak up carbon dioxide emissions from burning fossil fuels,” said Huntingford.

“Corporations both get revenue and expend it. Changes to either of these processes in response to taxation change have profound implications for how much the economic system retains capital from net earnings.” Say more or less all economists.

Do corporate revenues and expenditures tell us how the economic is growing or do we know the economy is growing because the GDP grows?

Hint: GDP is measured at factor cost, the factors being capital and labor (i.e. jobs).

What we know is that the world has been greening at the same time it has been accumulating capital and creating jobs.

NASA study: Carbon Dioxide Fertilization Greening Earth, Study Finds

So does the CO2 flux tell us how much plants act as carbon sinks by inhaling and exhaling or does the accumulated green matter that NASA has measured tell us that the net CO2 retained is increasing?

Hint: carbon and oxygen (CO2) and H2O form sugars, starches and cellulose that plants incorporate into their green matter.

Study finds that emission rates are 30 percent higher than previously predicted
so plants are growing 30% faster than predicted. while in a sane world this would be a good thing, in the newspeak world this becomes a bad thing. everything to do with. co2 is automatically worse than we thought. which means previous thoughts are never accurate.

in a greening world the underlying assumption that nature is in balance except for human emissions is clearly wrong.

“this may reduce the ability of Earth’s land surface to absorb emissions due to fossil fuel burning.”…
if something “may” be true it may also be false. this sentence tells us nothing.

why do scientists feel the need to speculate? where is the science in this?

Jacob Frank

So plants aren’t rabid marxists, got it. I wonder if old communists ever lament their ideology has been overtaken by worshipers of the CO2 molecule? I mean they did frown on religion at one time.

“For pre-industrial estimates, new baseline Rd increases Rp and especially in the tropics. Compared to new baseline, revised instantaneous response decreases Rp for mid-latitudes, while acclimation lowers this for the tropics with increases elsewhere. Under global warming, new Rdestimates amplify modelled respiration increases, although partially lowered by acclimation”

I’m not slogging through the article. Mostly because botany was a long time ago. However, here are a few things that shout at me from the abstract which tells me that while 30% may be higher–the observational bias still prevails. These things are:

1. Pre-industrial estimates. BUNK. Based on a supposition of what was there inferred by guestimate adjustments. In other words, the possibility of a confirmed maybe.

2. Compared to the new baseline: a new baseline based on No. 1.

3. Under global warming: See No. 1 and No. 2.

4. Amplify modelled (spelled wrong) respiration increases. Amplify means more, increases mean more..exactly WHAT did they modell(intentionally spelled wrong)? Observation bias.

After that abstract leads me to the possibility of a confirmed suspicion that this article is nothing more than bird cage lining.

I agree with the retired science teacher…where the hell is the real science? Biology and botany are real complex sciences, why in the hell are they tied with this climate schtick we are all subjected to? It’s very freaking simple here folks: WE DON’T KNOW 1/4 of biology–have really only begun to study it outside of medicinal purposes so why the heck are we cowtying to the arrogance of the 1800’s when it was declared that there was no reason to study science because everything was already known?

I think NASA needs several more trillions of dollars to be able to grow
spiderworts on the space station. Maybe in past experiments they forgot the sunlight.

My scientific analysis says that plants don’t need us, but we need plants. [except for rotating the bottle].


Oooo! Those wicked plants! We should get rid of them all.


Send them to Drax for incineration !!!

so plants respire
more co2 than we thought,
and this will add to GHG warming.

got it.


ye, they pump CO2 out of nowhere, you know, more of it now than before.
You “got it” as usual. Wrong.


From a carbon cycle point of view, having it wrong 30%, or even 2x, isn’t very important. 30% more out, 30% more in, pretty much the same balance. No big deal.

However, from a photosynthesis process point of view, this is STAGGERING.
the whole photosynthesis process use up HUNDREDS OF WATTS (tens for the synthesis part, and much more for the water cycle part that comes with it). A single 1% of this process is more important that the so-called “GHG forcing”. 30% unknown is just staggering, and anything that use these number, Earth’s energy budget, Models, etc. just got down the drain, especially when they pretended to have it right, despite such a huge flaw.


“The implications of this study are enormous,” Ming emphasized. “The fact that plant respiration is likely 30 percent higher than previous estimates should warn all global modelers that an updated inspection is warranted regarding how we model carbon flows in and out of terrestrial ecosystems globally.”

So Ming is suggesting that climate models be updated to account for this extra plant respiration to make them even more alarming. That way they can overestimate future warming even more than they currently do. Great!

Regardless of how much CO2 is released by plants, they are a net consumer of CO2. That hasn’t changed. The fact that they are not 100% efficient in converting CO2 to energy does not mean they are CO2 emitters. They use up more CO2 than they emit. Plant growth depends on it. So the more plants there are, the more CO2 is extracted from the atmosphere. This study does not change that fact.

Jerry Henson

From the abstract-
“To enable planning for climate change requires robust descriptions of atmospheric CO2 capture by photosynthesis (gross primary productivity; GPP) and release by plant (and soil) respiration.”

I did not find a description of the way that the researchers found that plants
release CO2. I have done experiments which confirm that the soil does.

The following article confirms my findings.

The CO2 emitted by the soil is not the topsoil digesting its self. The excess CO2
being measured is upwelling natural gas being being oxidized by methanotrophs,
enriching the topsoil and emitting CO2.

The reason CO2 is a trailing indicator of temperature is that the hydrocarbons rising
from great depth rise slightly faster as the earth gently warms from the LIA or any
extended cold period. The microbial culture blooms to consume the additional
“food”, increasing the CO2 output.

I have done experiments which confirm that natural gas is found below the
topsoil horizon. If the soil is not too wet or not frozen, the microbial culture
consumes it and converts it to CO2.

The methane balance put out by the USEPA several years ago claims that
upland topsoil is a 30TG sink for CH4. It is not. The hydrocarbons found in topsoil
upwell from below. When CH4 hits the atmosphere, it does not sink, it rises.

They do not understand the carbon cycle.