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Discussion > Why ARE levels of CO2 rising right now?

Whatever the reasons, levels of CO2 are now higher than at any time in the current ice age (assuming the ice core records are being correctly interpreted), and that is 750,000 years.
I dont believe that this has any implications for worrying short term future temperature but there has to be a reason.
I do not believe that it has been caused by human activity for the following reasons:

Murry Salby shows a graph where human emissions of CO2 are plotted along with global levels of CO2 (on a year to year basis). This same graph is shown for totally different reasons by Gavin C Crawley (of dreaded UEA origin). This graph shows that human emissions of CO2 have been rising steadily year on year by a fairly consistent small amount. The total CO2 graph is all over the shop, up 2ppm one year and down 2ppm over the next two years. There is no correlation on a year to year basis.
You can see the graph here:
Critics of Salby claim that he is wrong to ignore the trend in total CO2 which no doubt would be a similar graph to human emissions.
These criticisms invite two questions.
First what really is the mechanism by which CO2 is supposed to warm the atmosphere and why is temperature not "all over the shop" just like CO2?
Second just what exactly is causing this dramatic year on year fluctuation in global levels of CO2?
My own conclusion is that the fluctuations of global CO2 show that human emissions are totally disconnected from total global levels of CO2.

My own "knowledge" of past temperatures over the life of the planet is from
perhaps someone can point me at a better one? In this record most of the earth's history has been much warmer than today and could be said to be the norm. This actually fits quite nicely with the work of Svensmark.
You will know that Svensmark links the levels of cosmic rays reaching the surface of the earth to cloud formation and thus to cooling/warming. Experiments at CERN are confirming this.
The basic theory is that cosmic rays or sub atomic particles entering our atmosphere collide with molecules in the atmosphere and create new larger molecules. The large molecules that reach the surface are large enough to seed low clouds and so cool the earth.
The numbers of cosmic rays striking the surface of the earth are affected by a number of factors based on the sun.
The strength of the sun's magnetic field (Solar Wind) varies in cycles.
The earth's orbit around the sun is not circular and there are times when we are further away and times when we are closer.
The other sun factor is that the sun is moving around our galaxy, sometimes it is passing through one of the spiral arms and at other times it is far from other suns. This is important because when passing through a spiral arm we are closer to the super novas that are the source of all cosmic rays.
According to Svensmarks latest paper we are just leaving one of the spiral arms and about to return to deep space (this takes us away from any danger posed by the inhabitants of LV41 ^.^). The further from the spiral arm we get then the less cosmic rays will strike earth and the warmer it will become.
All of our records of sun spots (strength of the suns magnetic field) relate to a time when we are within a spiral arm and therefore receiving a lot of cosmic rays. We know that normally a solar minimum will mean cold but when we are out of the spiral arm I doubt it will make a difference.
Is the rise in CO2 some kind of effect of this transition that we are making from ice age to warm period?

Jun 25, 2012 at 11:09 PM | Unregistered CommenterDung

Here is what Robert Brown posted on wuwt . I think he's saying nobody knows for sure. There are plenty of models around but so what?

A second area where I personally think that the science is unsettled is in the Carbon Cycle. It’s all well and good to say that humans are dumping large amounts of CO_2 into the atmosphere, bad on us, that’s why the level is increasing, but the CC is a complex dynamic equilibrium process with multiple sources and sinks. Two of the sinks in particular have a total capacitance some two orders of magnitude greater than the entire CO_2 content of the atmosphere — the soil and the ocean. These sinks are capable of taking up all of the released CO_2 and sequestering it after only a short delay, and in fact are measured to be taking up an ongoing fraction of the anthropogenic CO_2 after an ongoing delay. However, the cycle itself is not without feedbacks, and the time constants and coupling constants and relevant dimensionality of e.g. the Bern model used to predict the CC are not unique — other numerical models can be parameterized to fit the observations, and some of these models have very different interpretations and various virtues of their own. Some of them leave one with the troubling and not entirely unreasonable interpretation that the rising CO_2 level isn’t from anthropogenic CO_2 per se; it is because changing temperature alters the capacitance of the larger sinks to first order, shifting the equilibrium so that we are constantly chasing it as long as the oceans net warm in response to non- CO_2 forcings.

Obviously this system whichever differential description one uses is not unstable on the high side, or a warm stretch like the MWP or Holocene Optimum would “tip” the Earth right out of the ice age it is currently in. We know this because no matter how much CO_2 we release or will release, the oceans and soil can release (or absorb) much, much more. There are capacitance/resistance models that are nearly isomorphic to the CC.

Again, here I take the viewpoint of an outside observer. Having multiple models that all fit the data within the error bars, in the best of Bayesian unbiased reasoning, in and of itself decreases our object assessment of the likelihood that any particular one of the models is correct! Over time one can often do more research and — gradually — falsify one or more of the competing models but what one cannot do is look for more evidence that your favorite model is correct!

(I think the UEA guy's name is Cawley by the way.)

Jun 26, 2012 at 12:12 AM | Registered CommenterMartin A

My apologies Martin and as ever you are correct :)

Jun 26, 2012 at 12:22 AM | Unregistered CommenterDung

Salby did not ignore the trend. He showed that the high correlation of CO2 to temperature, which explains observed changes between years, also explains much of the observed trend in CO2:

It seems to even explain the change in the trend.

Jun 26, 2012 at 7:30 AM | Unregistered CommenterLiam S

Salby's work disconnects human emissions from fluctuations in global levels of CO2, in other words global levels of CO2 are controlled by natural emissions and sinks.
However the global levels of CO2 ARE rising and 400 ppm has recently been recorded. Salby says "not us mate" so it is natural but why then has nature suddenly decided to raise levels of CO2 to levels not seen for hundreds of thousands of years?
What is the mechanism?

Jun 26, 2012 at 8:46 PM | Registered CommenterDung

Is there a transcript of Salby's talk available anywhere? The sound quality on the video I looked at is so bad I can barely make out what he's saying. Plus it's difficult to think critically about what somebody is saying while they are rapidly moving ahead in their talk.

I'm open to being convinced by Salby. However, to me it is pretty convincing that the rise in atmospheric CO2 is man-caused. If you plot the excess Mauna Loa CO2 levels from 1960 to 2005, you find they are pretty consistently about half of the cumulative estimated total man-caused CO2 emission (fossil fuel + land use change), year by year, over the same period. Circumstantial evidence, but pretty clear so far as I can see.

Jun 27, 2012 at 8:40 PM | Registered CommenterMartin A


Did you look at the graph in Cawley's paper?
As far as I know there is not a reproduction of Salby's slides available anywhere on the net however there are many blogs with the video including Judith Currie. When I ran the video I had bad sound until I realised I had managed to get three running at the same time ^.^
The graph in Cawleys paper is to all intents an purposes the same as for Salby and shows that human emissions are totally disconnected from changes in global CO2.

Jun 28, 2012 at 12:16 AM | Registered CommenterDung

Dung - I screen scraped Salby's video to capture his graphs - I now have them in good quality. No need to look at Cawley's graph (though I have it, obviously).

I really would like to study Salby's words in detail. Even with good sound quality, it's difficult to think critically in real time while following someone's argument.

Jun 28, 2012 at 8:52 AM | Registered CommenterMartin A


Our "knowledge" of the Earth's past on CO2 informs us that in the earliest days of its history, the atmosphere was 80% CO2 or 800,000 ppm, now we understand that it is 400 ppm.
If the record at is correct then we assume that during all of that time the average global temperature varied between 10 deg C and 25 deg C.
According to The University Corporation for Atmospheric Research the average global temperature at the moment is about 14.5 deg C.
Life on Earth has survived and developed through this range of temperatures although obviously it has had to adapt.
What worries me is not the fact that temperatures might rise by 10 deg C but that in relative terms CO2 has almost disappeared from the atmosphere.
At around 180 ppm all currently existing vegetation will die and all life dependent on that vegetation will die. This I find somewhat worrying.

Jun 29, 2012 at 5:51 PM | Unregistered CommenterDung


The fact that something has not happened yet does not constitute proof that it won't happen. Nonetheless, after three billion years of CO2 levels having been adequate to support life, and levels rising at present, I have other things higher on my own list of things to worry about.

On my to-do list for next week is to look carefully at Salby's slides. It would be nice if, at a stroke, his paper knocks the whole "CO2 = catastrophe" meme on the head. Though I'm not counting on it.

When the "cold fusion" thing came out years ago, it seemed obvious to me the whole thing was nonsense - if only because the experimenters were not dying from gamma exposure from their unshielded setup. But I imagine that the management of centres involved in fusion research worried at night (for a night or two at least) that there might actually have been something in it.

Jun 30, 2012 at 6:34 PM | Registered CommenterMartin A

Here is a transcript of Salby's talk.

I'm looking forward to reading it.

Jun 30, 2012 at 7:57 PM | Registered CommenterMartin A


Well done!

For me there are several papers, articles and facts that should already have knocked CAGW on the head but nobody is listening.

Jun 30, 2012 at 8:49 PM | Registered CommenterDung


At around 180 ppm all currently existing vegetation will die and all life dependent on that vegetation will die. This I find somewhat worrying.

This is puzzling. CO2 levels fell below 180ppmv for about 3000 years during the glacial maximum 660 - 670ka (Luthi et al. 2008) and there wasn't a planetary extinction of all vegatation and all life dependent upon it. Unless vegetation and all life dependent upon it re-evolved from scratch over the last 660ka.

Carbon dioxide levels are below 180 parts per million by volume (p.p.m.v.) for a period of 3,000 yr during Marine Isotope Stage 16, possibly reflecting more pronounced oceanic carbon storage. We report the lowest carbon dioxide concentration measured in an ice core, which extends the pre-industrial range of carbon dioxide concentrations during the late Quaternary by about 10 p.p.m.v. to 172–300 p.p.m.v.

Here's the close-up of the CO2 reconstruction from the bottom of the EPICA Dome C Antarctic ice core:

CO2 below 180ppmv (EPICA Dome C)

Now this could be wrong. It's from right at the bottom of a deep core. But *all* Antarctic cores provide evidence for CO2 at ~180ppmv during glacial maxima 400ka - present. If this was a threshold kill value for vegetation, you'd expect evidence of die-backs in temperate latitudes that could not be correlated with temperature. To the best of my knowledge, none has ever been found. If you have some references I'd be interested to see them, so please post up the links.

Jun 30, 2012 at 10:55 PM | Unregistered CommenterBBD

I missed it at the time, but there was discussion of Salby's talk here at BH.

An oral presentation is different from a written published paper - the speaker has their work cut out to get their key message across without confusing the audience with conflicting statements.

What I hope is that, when Salby's paper appears in print, we'll find that he has done what Feynman said you should do - include the arguments against your hypothesis and list they open points that you have not succeeded in addressing.

Jul 1, 2012 at 11:12 AM | Registered CommenterMartin A


That is good info mate and I will follow your links and read up. However obviously although my figure is the lowest figure I have read for the lowest CO2 level able to support vegetation it may not be exactly right also I guess vegetation does not die out the very second CO2 hits any given level. Will come back on this after I read more.

Jul 1, 2012 at 2:21 PM | Registered CommenterDung


OK I read quite a few references and there are just as many estimates ^.^. However there seems to be a dreaded consensus around a figure of 150 ppm at which most plants will stop growing NOT die as I thought. However if plants do not grow they will not feed humans or any other animals so life as we know it would be over.
Ken Caldeira at the Carnegie Institution for Science (PHD Atmospheric Sciences) estimates that as our sun warms CO2 will disappear completely in about 100 million years.
So to respond to you BBD, my estimate might be a little high. In addition seeds, spores, roots and tubers would last almost for ever so that if conditions changed they could flourish again. However the long term problem does seem to be the loss of CO2 and not any increases in CO2.

Jul 1, 2012 at 3:43 PM | Registered CommenterDung


Going right back to your original questions about how we know it's us etc.

Look at the last ten thousand years (10ka) from ice cores. Everything bumbles along at the bog standard interglacial ~280ppmv CO2 for the entire period but then, suddenly, in the second half of the C20th, BANG!

Now, what's changed radically in terms of CO2 sources over the last 10ka? With a huge increase from about the mid-C20th sufficient to account for the observations? Yup, 'clever monkeys' is the correct answer.

The red bit on the inset graph of CO2 concentrations from 1750 (top panel) is the direct atmospheric measurement aka the 'Keeling curve' after the chap who got it going back in the 1950s.

Here's the classic plot, showing CO2 measured by the Mauna Loa station. Thanks to the good offices of WfT it's bang up to date: 1958 - May 2012. The annual cycle you see is the uptake of CO2 by vegetation in the NH summer and the release by decay during the NH winter. The steep upward trend is the result of anthropogenic CO2 emissions accumulating in the atmosphere faster than natural sinks can remove them.

Plants 'prefer' the light δ12C isotope of carbon, and CO2 formed by burning plants - and fossil fuels - has more of the light δ12C isotope. CO2 from other sources has more of the δ13C isotope. If the majority of the increase in atmospheric CO2 is from burning fossil fuels then the amount of δ13C *relative* to the amount of δ12C would fall. This is exactly what has happened.

See the detailed monitoring work presented in Keeling et al. (2010):

The 13C isotope is stable and heavier than the normal form of carbon (12C), and plants tend to selectively assimilate the lighter isotopes during the photosynthetic process. This results in the following features of the 13C/12C ratio in the atmosphere: (1) a seasonal cycle occurs with the heavier isotope at relatively high concentrations during the summer, as plants selectively remove the lighter isotope from the atmosphere, and (2) a general decrease with time, as more fossil carbon (which originally was plant material, and consequently biased toward the lighter isotope) is injected into the atmosphere from the combustion of fossil fuels.

δ13CO2 Mauna Loa 1977 - 2008.

Same thing, but at the South Pole.

Same thing but Alert station, NWT Canada
, the northernmost monitoring station (the best approximation to the North Pole)

There are 11 monitoring stations in the study - you can view the rest
. The fall in the relative amount of δ13C is clear in all data sets and is obviously global.

So, we've got a known, quantified source sufficient to explain an increase in CO2 unprecedented in the last 10ka (actually, vastly longer than that - CO2 only gets above ~285ppmv once (MIS9) in the last 800ka). On top of that, we've got unambiguous isotopic fingerprinting. A powerfully persuasive combination.

A final point. You referenced Deltoid in your original comment at the start of this thread. The article there is helpful and I recommend that you revisit it.

Bearing our previous discussion about the lower bound for CO2 during glacial maxima, you might want to pay extra attention to the concluding quote from John Nielsen-Gammon. JN-G is recalling his discussion with Selby after the latter's presentation (emphasis mine):

In discussing what his [Salby's] model would mean for past variations of temperature and CO2, it eventually became clear that he believed all paleoclimate data that supported his statistical analysis and disregarded all paleoclimate data that countered his statistical analysis, even though the latter collection was much larger than the former.

Eventually I realized that if 0.8 C of warming is sufficient to produce an increase of 120ppm CO2, as Salby asserted, then the converse would also have to be true. During the last glacial maximum, when global temperatures were indisputably several degrees cooler than today, the atmospheric CO2 concentration must have been negative.

That was enough for me.

Jul 1, 2012 at 7:20 PM | Unregistered CommenterBBD


I appreciate your reply and the effort that you have put into it. however at the moment I do not accept some of the basics you included.

Firstly my original question was/is "Why ARE levels of CO2 rising right now?". They are indeed rising and have already reached levels not seen in the last 750,000 years.
The part of Salby's work that I am interested in is the disconnection of human emissions of CO2 from changes in global levels of CO2. As I already stated the same graphs were used by a guy called Cawley who was in fact trying to prove something totally different.
My question has nothing to do with warming as a function of CO2 or vice versa, I have already seen enough papers to convince me that CO2 is not the cause of warming at current temperatures and levels of CO2.
Just to (I think) agree with something you said; I do not think CO2 was the cause of any warming in Salby's graphs.

Jul 1, 2012 at 9:06 PM | Registered CommenterDung

"During the last glacial maximum, when global temperatures were indisputably several degrees cooler than today, the atmospheric CO2 concentration must have been negative.
That was enough for me."

That might have been enough for JN-G to feel he need pay no more attention to Salby's work, though I am not sure why he would feel confident that the relation between temperature and CO2 release has to be linear.

To me, the striking thing in Salby's presentation is the almost identical waveform of CO2 and temperature from around 1982 to 2007 - and the same, in the inverse sense, for δ13 and temperature. (He filtered the data to remove frequency components at frequencies higher than 0.5 cycle per year so that the annual cyclic variation was suppressed.) See his graph labelled "Net Global Emission" in the Youtube video of his presentation at 19:08

I could not help noticing that both of these curves are almost sinusoidal, with around six complete cycles from 1984 to 2006. So both the CO2 record and the temperature record both have a strong frequency component at 6/(2006-1984) = 0.27 cycles per year.

If one did not cause the other, is there something that could be the cause of both of these effects?

It does seem interesting that 0.27 cycles per year is the third harmonic of the sunspot cycle frequency: 3/11 = 0.27 cycles per year. A coincidence? If so, what else could account for the identical periodicity of the two records?

Jul 1, 2012 at 9:11 PM | Registered CommenterMartin A


I do have a closed mind when it comes to temperature/CO2 (I know that is bad) because in the ice core records temperature leads CO2 indeed but by 800 years and higher.
The last interglacial was at least 3 deg C warmer than this one but with lower levels of CO2.
Right now CO2 is behaving outside the box (of our experience) so I asked why? If it was temperature we would surely have seen that happen somewhere else.
Your observation of the sunspot link is quite brilliant hehe.
My understanding of sunspots is that they relate only to the strength of the suns magnetic field and by effect, the rate at which cosmic rays strike the earth. How could that be affecting CO2?

Jul 1, 2012 at 11:09 PM | Registered CommenterDung

The big picture suggests that the increase in atmospheric CO2 and sunspot numbers don't correlate.

And what is the source of the light carbon, if not fossil fuels? Let's not forget that we *know* that we are adding about 30GT CO2/annum to the atmosphere. So, if it's not us, then what on Earth is it and why does our contribution somehow disappear? ;-)

Jul 1, 2012 at 11:19 PM | Unregistered CommenterBBD


When I first read about the "smoking gun" of Carbon 12 I must admit I worried that I had been wrong. However first I figured out that deforestation would increase the number of C12 CO2 molecules because the forests would not be there to absorb them. I also had other worries about the fact that the theory had only one "strand", it considered only the burning of fossil fuels before deciding that fossil fuels were indeed the reason. They did not check all the other sources of atmospheric CO2 and consider whether they might be increasing or decreasing the amount of C12 CO2 in the atmosphere.
If plants prefer C12 CO2 then there would very soon be no C12 CO2 left unless its was constantly being replenished; by what?
On sunspots I am not saying you are right but right now I do agree that "the big picture" suggests that sunspots do not control CO2.

Jul 1, 2012 at 11:30 PM | Registered CommenterDung


Okay, never mind me, but what's up with WUWT? :-)

Ferdinand Engelbeen has a four part series there of guest posts explaining why the measured increase in CO2 is anthropogenic.

Part 4 has links to parts 2 and 3.

If plants prefer C12 CO2 then there would very soon be no C12 CO2 left unless its was constantly being replenished; by what?

Burning coal made of fossil plants with a fossilised light isotopic signature. I mentioned this above @ Jul 1, 2012 at 7:20 PM: Keeling et al. (2010).

Jul 2, 2012 at 12:11 AM | Unregistered CommenterBBD

Jul 1, 2012 at 11:09 PM CommenterDung

My understanding of sunspots is that they relate only to the strength of the suns magnetic field and by effect, the rate at which cosmic rays strike the earth. How could that be affecting CO2?

Dunno. How about the following?
1. Sunspots affect cosmic rays reaching the earth.
2. Cosmic rays reaching the earth result in (or accentuate) cloud formation. Maybe.
3. Clouds increase the proportion of sunlight reflected before reaching the earth's surface.
3a Clouds result in rain.
4. Incident light level affects uptake of CO2 by the biosphere
4b Rain levels affect uptake of CO2 by the biosphere

"Cloud formation may be linked to cosmic rays" Not sure why that should have been regarded as news - the Wilson cloud chamber has been used for 100 years to detect the tracks of high energy particles by condensing vapour on the trail of ionised atoms resulting from the transit of a high energy particle.

I found this...

"The general level of solar activity doubled or tripled from 1900 to 1950, an estimate based on sunspot numbers and on the intensity of geomagnetic activity. This increase suggests an increase in solar luminosity by perhaps one part in 2000, and the author suggests it is interesting to note that the mean temperature in the northern temperate zone, as well as the surface sea water temperatures, rose during the same period. "Warmer seas, of course, reduce the rate at which atmospheric carbon dioxide is absorbed into the oceans. It appears that the global warming since 1950 is in part a consequence of the continuing increase in solar brightness, seriously aggravated by the extravagant burning of fossil fuel. So the mystery of the variations in the total luminosity of the Sun is part of the complicated picture of global warming."

Jul 2, 2012 at 11:32 AM | Registered CommenterMartin A


I will go read WUWT ^.^

Martin your last paragraph is straight out of Svensmark:

More sunspots --> stronger solar magnetic field -->less cosmic rays striking Earth's atmosphere --> fewer low clouds seeded --> warming.
However this would also mean less rain and more CO2 take up by plants and since CO2 rose right through that period it means that your effects 4 and 4b are only a small influence.

Jul 2, 2012 at 1:58 PM | Registered CommenterDung