Is Mother Nature the main driver of fluctuating CO2 levels?

[zankaon]

Svalbard CO_2 peaked at 397; now 393. NOAA, incorporating 60 sites, has CO_2 386. Rate of yearly increase at ~2 ppm, an increasing rate in comparison to past. A non-linear accelerating proxy curve? Are effects of global warming also on a non-linear accelerating rate curve? http://www.guardian.co.uk/environment/2009/apr/27/arctic-carbon-dioxide-levels"

 

[sylas]

Svalbard CO_2 peaked at 397; now 393. NOAA, incorporating 60 sites, has CO_2 386. Rate of yearly increase at ~2 ppm, an increasing rate in comparison to past. A non-linear accelerating proxy curve? Are effects of global warming also on a non-linear accelerating rate curve? http://www.guardian.co.uk/environment/2009/apr/27/arctic-carbon-dioxide-levels"

Not "vs". This is just different measurements at different locations. You should not expect the global mean value to be identical to the value at one station. Your link describes it well.

Note, however, that your link is a second hand account, in a newspaper. In this forum we should really be going to primary sources in the scientific literature, or other reliable sources. I'll have a quick look around.

 

[Richard111]

I am lead to believe CO2 is a heavy gas and does not float freely in the atmosphere and is moved by wind and consequent turbulance. I would have expected a lower reading of CO2 at Svalbard. But it just occurred to me that the climate at Svalbard being colder, would have less precipitation to wash out the CO2. All very confusing to the layman.

 

[sylas]

As promised, some links. These are not "peer reviewed" scientific literature, but rather reports of basic measurements from well regarded scientific bodies. They are not presenting new research, but measurements.

The newspaper article mentions the NOAA summary. It can be found as: Greenhouse Gases Continue to Climb Despite Economic Slump, from NOAA on April 21, 2009.

The main NOAA page for regular carbon dioxide measurements is Trends in Atmospheric Carbon Dioxide (NOAA measurements). This page gives the Mauno Lua measurements in Hawaii, and also a global mean number. The two numbers differ slightly.

The data page for measurements at Zepplin Research Station, Svalbard, is http://www.itm.su.se/zeppelin/data_co2.html.

 

[sylas]

I am lead to believe CO2 is a heavy gas and does not float freely in the atmosphere and is moved by wind and consequent turbulance. I would have expected a lower reading of CO2 at Svalbard. But it just occurred to me that the climate at Svalbard being colder, would have less precipitation to wash out the CO2. All very confusing to the layman.

The extra weight of CO2 (molecular weight 44, by comparison with 32 for Oxygen and 28 for Nitrogen) is not enough to make a significant difference in the troposphere. It is a "well mixed gas", and you don't get any appreciable fractionation by molecular weight until above the tropopause.

It makes more difference how close you are to the major sources of carbon dioxide. The Zepplin station is closer to the industrial centers of Europe than the Mauno Lua station out in the middle of the Pacific, and this is most likely the main reason for higher levels there.

I do not think rain has any effect of washing out carbon dioxide.

 

[vanesch]

I am lead to believe CO2 is a heavy gas and does not float freely in the atmosphere and is moved by wind and consequent turbulance.

That's not really possible, or we would all be suffocating!

 

[Xnn]

I checked out NOAA’s site for CO2 measurements and downloaded the Mauna Loa monthly mean data set. As far as I know, it’s has the longest running high precision record of CO2 measurements besides being in an excellent location.

Put the data set into an Excel spreadsheet and started checking things out.
Anyhow, the seasonally adjusted value for August 2009 is 387.63 ppm.
The rate of rise compared to a year ago is 1.8 ppm.

Was curious to see how this yearly rise compares to the past.
So, I set up a simple calc and graphed it….hmmm interesting!

Unfortunately, we are not supposed to display such graphs (even though they are very simple to do), so about all I can do is wave my hands at the kepboard and invite others to try Excel if you doubt me. Here is what I found:

The yearly rate of rise has risen since 1959. This isn’t too surprising since the world economy has grown since then. The rate of rise used to be about 0.8 ppm/year while now its closer to 2.1 ppm. The rate of rise was slightly above 2.1 during March and April of this year, and there is so much scatter that I wouldn’t never claim that it’s recently slowed down due to the economic slowdown.

However, what’s really interesting is that the greatest yearly rise occurred way back in August 1998, which some may recall was during an El Nino period. In fact it wasn’t just 1 month in 1998, but there was a good 8 month period of time in 1998during which the rate of rise was greater than usual.

So, while it is clear that human activities are steadily driving CO2 levels higher, don’t count Mother nature out of the picture. If the winds shift just right and ocean currents stagnate, we could witness a great acceleration in the rate that CO2 is rising.

 

[sylas]

Unfortunately, we are not supposed to display such graphs (even though they are very simple to do), so about all I can do is wave my hands at the kepboard and invite others to try Excel if you doubt me. Here is what I found:

I have not seen this listed explicitly in the guidelines. What we have is very sensible (IMO):

Controversial claims must be supported by evidence that comes from a scientific, peer-reviewed journal or a similarly reliable source, i.e., unsubstantiated claims are not allowed.

My understanding is that there is no problem with quoting a peer reviewed source for a claim, but that it is not appropriate to to use data or information from such a source as evidence for a claim of your own that is not explicit in the source itself.

The rate of increase of CO2 is not a "controversial claim", or it shouldn't be. There is some "controversy" over the source of the measured increases, to which you allude in your post, and that can be addressed with appropriate journal references. But the rate of increase itself, including acceleration of the rate, is not controversial, as far as I know. The source for instrumental measurement in this case is (in my view) "similarly reliable" as a peer reviewed publication. So I can see nothing wrong with repeating the graph supplied at the official page, http://www.esrl.noaa.gov/gmd/ccgg/trends/. The site is currently not responding for me.

Also: a quick comment on the use of peer-reviewed references. Most people know this if you stop to think. A peer reviewed reference is not a finished scientific case that is accepted by default as valid. It is rather a scientific case that has passed the first hurdle for consideration in the wider scientific community. Therefore the requirement for peer review does not mean we only get hold of definite claims that have been scientifically proved and may not be disputed. It means that we avoid wasting time on claims that are scientifically worthless. If a claim has real merit, you should be able to find the claim made in the literature. It's not a perfect system, but it's a good practical requirement for PF in a contentious topic with a lot of bad information around.

I'm giving the references here not as a proof of the one true answer to what you have seen, but as a seriously proposed answer which has good scientific support. You are most likely observing the effects of changes to fluxes in the carbon cycle.

The likely cause of accelerated CO2 in 1998

In any case, here is a legitimate peer-reviewed reference which deals specifically with the phenomenon you have mentioned. 1998 stands out as being an exceptionally strong El Nino year. This leads to a change in the natural fluxes of the carbon cycle, with additional CO2 being maintained in the atmosphere. It is not so much that there's a different source of CO2 involved, but that there is a change in how carbon is distributed around the various reservoirs of the carbon cycle. Anthropogenic emissions continue to be the main source by far of increasing carbon within the various reservoirs of the carbon cycle, of which the atmosphere is only one. Here is a reference for this:

• Cox, P.M. et. al. (2000) Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model, in Nature 408, 184-187 (9 November 2000) | doi:10.1038/35041539

Extracts (selected to focus on the El Nino link for accelerated increase in atmospheric CO2)

The continued increase in the atmospheric concentration of carbon dioxide due to anthropogenic emissions is predicted to lead to significant changes in climate. About half of the current emissions are being absorbed by the ocean and by land ecosystems, but this absorption is sensitive to climate as well as to atmospheric carbon dioxide concentrations, creating a feedback loop. [...]
...
The simulated carbon cycle displays significant interannual variability, which is driven by the model-generated El Niño/Southern Oscillation (ENSO). A realistic response to internal climate variability is an important prerequisite for any carbon-cycle model to be used in climate change predictions. Fluctuations in annual-mean atmospheric CO₂ are correlated with the phase of ENSO, as indicated by the Nino3 index (Fig. 1). During El Niño conditions (positive Nino3), the model simulates an increase in atmospheric CO₂; this increase results from the terrestrial biosphere acting as a large source (especially in Amazonia), which is only partially offset by a reduced outgassing from the tropical Pacific Ocean. The opposite is true during the La Niña phase. The overall sensitivity of the modeled carbon cycle to ENSO variability is consistent with the observational record, demonstrating that the coupled system responds realistically to climate anomalies.​

The paper does not mention explicitly the 1998 event; but that was certainly the strongest El Nino in recent times. The paper is mainly model based, and the record of observations to which it refers above in the last sentence of my quoted abstract is cited to another paper, which came out before 1998:

• Keeling, C. D. , Whorf, T. , Whalen, M. & der Plicht, J. V. (1995) Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980. in Nature 375, 666–670

Abstract:

Observations of atmospheric CO₂ concentrations at Mauna Loa, Hawaii, and at the South Pole over the past four decades show an approximate proportionality between the rising atmospheric concentrations and industrial CO₂ emissions. This proportionality, which is most apparent during the first 20 years of the records, was disturbed in the 1980s by a disproportionately high rate of rise of atmospheric CO₂, followed after 1988 by a pronounced slowing down of the growth rate. To probe the causes of these changes, we examine here the changes expected from the variations in the rates of industrial CO₂ emissions over this time, and also from influences of climate such as El Niño events. We use the ¹³C/¹²C ratio of atmospheric CO₂ to distinguish the effects of interannual variations in biospheric and oceanic sources and sinks of carbon. We propose that the recent disproportionate rise and fall in CO₂ growth rate were caused mainly by interannual variations in global air temperature (which altered both the terrestrial biospheric and the oceanic carbon sinks), and possibly also by precipitation. We suggest that the anomalous climate-induced rise in CO₂ was partially masked by a slowing down in the growth rate of fossil-fuel combustion, and that the latter then exaggerated the subsequent climate-induced fall.​

Felicitations -- sylas

 

[Xnn]

• Keeling, C. D. , Whorf, T. , Whalen, M. & der Plicht, J. V. (1995) Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980. in Nature 375, 666–670

Abstract:

This proportionality, which is most apparent during the first 20 years of the records, was disturbed in the 1980s by a disproportionately high rate of rise of atmospheric CO₂, followed after 1988 by a pronounced slowing down of the growth rate. .​

Interesting paper…

The rate of rise in the late 80’s was somewhat accelerated as the paper points out, and I’d add that there was a particular spike around 1988. However, the growth rate actually remained near the mean trend up until around June of 1991. The June 1991 12 month growth being 1.9 ppm CO2.

June 1991 is of course when Mt Pinatubo erupted, which resulted in a global cooling of about 0.4C.

What followed in the CO2 record is a protracted period of below normal growth.
It wasn’t until April 1994 that the CO2 growth rate returned to above the mean.

So, there we have it.
Mother Nature can both accelerate or decelerate the rate of CO2 growth.

By the way, there were several instance of negative 12 month CO2 rates between 1959 to 1974, but nothing since then. The most recent low growth period was April 2008 at 0.8 ppm/year… La Nina!