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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

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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).
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)

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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
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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 15 or so. I've drawn the vertical cross-section
with exaggeration at the sea surface (waves) where most
of the 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 actually
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?
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The oceans are predominantly area - but remember
the cross-section to determine what happens at
each level

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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.
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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 |
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Getting the scale of CO2 in oceans
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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. |
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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.
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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.)
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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.
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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

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actual CO2 increase |
Solar irradiation - GHG
windows for CO2 & H2O |
CO2
in perspective: actual increase, actual GHG "windows" |
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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 seems to go... |
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Updated 26th March 2009
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