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CO2 flux, oceanic scale, solubility
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CO2 figures, cycle, solubility, GHG effect,
oceanic scale, and biosequestration

See Primer sections on CO2. See Forum CO2 and oceans - let's get the science right
Basic figures | Oceanic flux | Biosphere flux | Oceans & Temp | Do isotopes show fossil fuel use?
| Mauna Loa questions | Greenhouse gas effects | Popular errors |


CO2 - the basic figures & info

Carbon Cycle - figures
Cycle diagram
Carbon Sources - figures
The Carbon Cycle

Carbon Dioxide - Units and Scale
1 Gt (gigatonne - 10^9 tonnes) = 1 billion tonnes = 1 Pg (petagramme - 10^15 grammes)
1 ppm (parts per million) = approximately 2.12 Gt carbon
Methane and other greenhouse gases (GHG) are often measured as carbon dioxide (CO2) equivalent.
One CO2 molecule has molecular weight 44 = 12[carbon] + 2x16[oxygen].
Thus 12kg carbon is equivalent to 44kg carbon dioxide ie CO2 is app. 3.67 times heavier than the equivalent of C.
Each human being breathes out app. 1kg CO2 daily ~ 100kg C annually; global population ~ 7 billion
Thus CO2 from human respiration is app. 1/10 total human emissions (not including methane etc from domestic animals)

CO2 levels
CO2 & 13C variations
CO2 outgassing pressure
All these are affected by: oceans outgassing/absorbing, rainforests, & seasonal forests



Principal CO2 fluxes - the oceans & biosphere

In addition to the effects of Sun and ocean currents, we have to understand the factors at work in the huge annual CO2 flux, which dwarf our emissions by a factor of 30 or so. I've drawn the vertical cross-section with exaggeration at the sea surface (waves) where most of the ocean changes happen.
  • By Henry's Law, 49/50th of our CO2 emissions would be absorbed by the oceans in time, if other things were equal. Henry's Law says that CO2 at a given temp and pressure will find its equilibrium with approx. 49 parts dissolved in the oceans to 1 part in the atmosphere.
  • In this case, even after 50 years of emissions, the overall increase would only be what we currently see annually, aroung 8Gt, which is still only a tiny fraction of the 700 Gt CO2 in the atmosphere. Doubling the CO2 concentration would then take 50 x 700 / 8 years, or approx 4500 years.
  • Many excellent studies show (see Segalstad) that CO2 only stays in the air around 5 years. No study shows a longer "life span" than 12 years.
  • The fact that the annual increase is 50 times what we might expect from our emissions by Henry's Law, warns us that another factor may be at work.
  • BUT, although the oceans are far more surface than depth, when we take a vertical cross-section, we only see a small "surface effect". So it may take time for Henry's Law to work. But how long?

CO2 theoretically expelled - for 1 deg C sea surface temperature rise - How many gigatons CO2 will the ocean outgas for 1ºC rise in satellite-measured Sea Surface Temp? From Endersbee (below) we know the actual rise in CO2 ppm (divide the weight in gigatons by 2 to get the approx. concentration ppm). In what proportions is the difference between the total theoretical outgassing as per Henry's Law (if the whole ocean temp rose 1ºC), and the ppm "pressure" level actually measured, due to

  • (a) only the sea surface exchanging CO2 quickly as per Henry's Law, the rest being much slower (inertia of water - vertical effect - is there an "equivalent depth" describing full rapid mixing?)
  • (b) sea surface only (or rather, an "equivalent depth") warming 1ºC?
  • (c) sequestration by plants and marine animals (calcifying processes) before extra CO2 can effectively get included in the ppm figure (is the ppm a proxy for "pressure due to SST" rather than an absolute amount?)
  • (d) rising anthropogenic CO2 emissions?


The oceans are predominantly area - but remember the cross-section to determine what happens at each level

Getting a picture of the huge oceanic flux


  • IPCC neglect Henry's Law and the biosphere. They have tried to fudge the data, starting with Bolin's "buffer", going on to multiply the well-known CO2 atmospheric lifetime by a factor of 10 or so, then to partition off our emissions from the natural CO2 when needed to get the right isotope figures, and to mix it all up when otherwise needed.
  • Floor Anthoni has brought to light a very important concept: that, in the biosphere, CO2 levels represent not QUANTITY but PRESSURE... "pressure" encourages the plants to grow more (which they like and we want)... a rising CO2 level must also take account of a higher rate of biosequestration which lessens the rise of the atmospheric CO2 level.
  • The biosphere flux is essential to factor in, as a homeostatic regulator - as happens with volcanic CO2, natural CO2 vents, and CO2 dissolved from minerals - otherwise the earth would lose the carbon needed to support life in marine CaCO3 deposition.
Getting the scale of biosequestration


CO2, the Oceans, and Temperature

CO2 and the oceans.

The total release of CO2 for 1 deg C SST rise would be calculable from the solubility change, if we can "guesstimate" what depth of ocean effectively partakes in this SST change, and therefore what global volume of water we have to start from, to calculate the CO2 actually released by overall SST rise of 1ºC.

CO2 solubility by proportion of mass at atmospheric pressure, is approx. 0.28% @ 5ºC; 0.23% @ 10ºC; 0.20% @ 15ºC.

CO2 solubility change per degC (sink/outgassing power) - Here we have the solubility of CO2 in pure water. If you measure the slope of these graphs, this yields a solubility change per degree Centigrade of approx. 3.9% @ 5ºC; 3.45% @ 10ºC; 3.0% @ 15ºC. Salinity only makes a small difference - not an essential issue for now.

Glassman has a brilliant page The Acquittal of CO2


Getting the scale of CO2 in oceans

Ocean area is 360,000,000 sq km = 360 x 10^12 sq metres
Ocean Mass: 1 gigatonne (Gt) = 10^9 tonnes = 10^12 kg = 10^12 m^3 water

Volume of oceans to 3m depth = 360 x 3 x 10^12 m^3 ie approx. 10^15 m^3
Mass of oceans to 3m depth
= 10^15 / 10^9 Gt = 10^6 Gt
CO2 dissolved to 3m
at 15ºC = 10^6 x 0.2/100 Gt = 2,000 Gt
CO2 outgassed for 0.1ºC temp rise
= 2,000 x 0.3/100 Gt
= 6 Gt ie one year's emissions

CO2 outgassed from 30m depth for 1ºC global temp rise = 600 Gt ie near-total atmospheric content
IMO, this scale explains the "jagged" CO2 rise (Engelbeen's graph, below) compared with the smooth emissions curve - the jagged line is hardly jagged at all in the context of the total flux.

Which Leads the other? Temp or CO2?

Referring mainly to Segalstad, I believe that the CO2 rise is ALMOST ALL due to the sun on the oceans.

Josh Hall shows CO2 follows SST with hardly any correlation in reverse. Since the Greenhouse Gas effect supposedly reached near-maximum at concentrations even lower than we started with, the lack of correlation with CO2 "driving" temp is to be expected.


Rising CO2 - from Sea Surface Temp, or from our Emissions?

Check out the core science in my primer.

Look at Endersbee's original piece. Together with the work of Josh Hall and Segalstad, Endersbee seems crucial in pinpointing sea surface temp as a likely originator of CO2 levels. This very high level of correlation seems highly unlikely unless it is because of causation. But the amount of smoothing is very high, the overall period being only a few years more than the 21-year moving average - this lowers the confidence we can put in this result.


It seems there's another spanner in the works... Mauna Loa CO2 levels seem to fit our rising emissions closely as well. However... there is a problem. The cumulative emissions curve's slopes do not agree with the CDIAC/BP annual emissions graph. See below.

Black Curve: Seasonally adjusted monthly average atmospheric carbon dioxide concentration 1959-2009 at Mauna Loa Observatory, Hawaii (20°N, 156°W) where CO2 concentration is in parts per million in the mole fraction (p.p.m.). Red Curve: Fossil fuel trend of a fixed fraction (57%) of the cumulative industrial emissions of CO2 from fossil fuel combustion and cement production. This fraction was calculated from a least squares fit of the fossil fuel trend to the observation record ranging from 1958 through 2006. (from Scripps CO2 Program. Last updated March 2009.)

Engelbeen's graph of annual increases show a very rugged air CO2 increase alongside a very smooth human CO2 increase - does this indicate (a) nothing more than a coincidence of scale; (b) natural causation? Which (if ANY) graph proves the true cause of CO2 rise???

If you measure Endersbee's SST slope, it shows 150ppm (300 Gt) apparent actual CO2 rise per degC SST rise (at 15ºC). But Climate Audit forum told me that the time span is too short for the figures to be trustworthy. Still, if true, they are significant, and it's worth keeping an eye open.

Even so, our emissions are still only a fraction of the huge outgassing one would expect from Henry's Law, if the upper oceans' temp. rose by 1ºC.


Carbon isotopes as indicators of natural causes of CO2

The dropping proportion of 13C has been taken by warmists to indicate that the atmospheric CO2 rise is of human origin. See for instance Tamino: It's a Gas. Carbon-14 was formed during atomic bomb tests; carbon-13 is not the preferred plant uptake either now or in coal; carbon-12 is the common carbon isotope. 14C, 13C and 12C measurements all seem to support NATURAL CO2 (see Segalstad). Now this has been verified further by Tom Quirke in Energy and Environment, Volume 20, pages 103-119. His abstract says:

Sources and Sinks of Carbon Dioxide

THE conventional representation of the impact on the atmosphere of the use of fossil fuels is to state that the annual increases in concentration of CO2 come from fossil fuels and the balance of some 50% of fossil fuel CO2 is absorbed in the oceans or on land by physical and chemical processes. An examination of the data from:

i) measurements of the fractionation of CO2 by way of Carbon-12 and Carbon-13 isotopes;
ii) the seasonal variations of the concentration of CO2 in the Northern Hemisphere; and
iii) the time delay between Northern and Southern Hemisphere variations in CO2,

raises questions about the conventional explanation of the source of increased atmospheric CO2. The results suggest that El Nino and the Southern Oscillation events produce major changes in the carbon isotope ratio in the atmosphere. This does not favour the continuous increase of CO2 from the use of fossil fuels as the source of isotope ratio changes. The constancy of seasonal variations in CO2 and the lack of time delays between the hemispheres suggest that fossil fuel derived CO2 is almost totally absorbed locally in the year it is emitted. This implies that natural variability of the climate is the prime cause of increasing CO2, not the emissions of CO2 from the use of fossil fuels.



Greenhouse Gas: putting the effect in perspective

actual CO2 increase
Solar irradiation - GHG windows for CO2 & H2O
CO2 in perspective: actual increase, actual GHG "windows"


CO2's low & diminishing GHG effects @ actual CO2 levels


Popular errors & misconceptions

If people know that all the extra CO2 is beneficial to plants and sea life, and totally follows temperature, and causes no appreciable extra greenhouse effect, the whole AGW nonsense falls apart, and the link between rising CO2 levels and human contributions doesn't even matter. But it would be nice to know.

We need to show these bio-physical dynamic fluxes clearly enough and provably enough, as well as show that the manmade figures just do not compute. It's not just a dynamic balance in the physics, it also involves the biosphere. The natural flux figures are so large as to shout out this possibility - but people behind computers forget the awesome size and power of the oceans and the biosphere.

Is there ANY temp-amplifying feedback from CO2 increase? No!
ha! got a clincher, bluster! at RealClimate:What does the lag of CO2 behind temperature in ice cores tell us about global warming?
People forget the oceans in the CO2 annual flux - Greenpeace omits them. See above.

This is an issue that is often misunderstood in the public sphere and media, so it is worth spending some time to explain it and clarify it. At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so. Does this prove that CO2 doesn't cause global warming? The answer is no.

The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data...

and that is as far as the proof actually goes...

Updated 26th March 2009


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