EPA document supports ~3% of atmospheric carbon dioxide is attributable to human sources

Hockey Schtick says
“‘Regarding taking down this post: if you removed this post all the comments would go away.’
Not so, I’ve saved all the comments and will repost them as well, although none of them relate to the issues…”
Just for clarification, my real point was that the comments on posts on WUWT are enjoyable and informative. The last three hours worth of comments are a perfect example of that. I wasn’t trying to imply that anything would be disappeared or that anything shady was about to happen. I’m just a random reader of this blog who enjoys it 🙂

Hockey Schtick says:
July 29, 2014 at 3:15 pm
As Bart and others have explained to you on many threads, your mass balance argument is a single equation with two unknowns, thus proves nothing. In addition, since T leads CO2 on short, intermediate, and long-term timescales, the cause does not follow the effect
HS, as explained in the above examples, the two unknowns don’t play any role at all. It is only the difference at the end of the cycle which matters. It doesn’t matter how much water circulates over a fountain, the pool will overflow if you add only 1% or 0.1% of the circulating flow. Neither does it matter that a factory doubles its throughput: that may give more gain, less gain or even a loss.
The same for the mass balance: it doesn’t matter that one year the natural cycle was 150 GtC in and 154 GtC out and the next year 300 GtC in and 302 GtC out. In all past 55 years there was more natural out than in…
Further, Bart’s arguments were based on the fact that there was a (not so) good agreement between temperature and the CO2 rate of change. That agreement is in the variability, not in the slope, as that are the results of different processes. One can match any linear slope with any other linear slope, that is only a matter of choosing the right factor but has nothing to do with cause and effect.
The only point where Bart could be right is if the natural carbon cycle increased a 3-fold together with the human emissions: then and only then the natural cycle could dwarf the human emissions. But there isn’t the slightest sign that the natural carbon cycle even increased over the past 55 years: the residence time didn’t decrease a 3-fold, instead it slightly increased. There is no sign that the seasonal vegetation cycle increased a 3-fold or that the oceans released and absorbed 3 times more CO2…
Further T leads CO2 on seasonal and (opposite!) on year by year variations. CO2 follows temperature on decades to multi-millennia, but over the past 160 years CO2 is growing much faster than the temperature dictates (8 ppmv/°C) over the past 800,000 years:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/antarctic_cores_001kyr.jpg
The MWP-LIA transition is visible as a ~6 ppmv drop in the Law Dome DSS ice core:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_1000yr.jpg
The same for the (reverse) HS in δ13C:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.jpg
But nature should be the cause of the CO2 increase after 800,000 years simply following temperature with exact the same timing as humans started to emit twice the amounts of CO2 as found as increase in the atmosphere?

Phil. says:
July 29, 2014 at 2:44 pm
In addition, as I explained to Richard, if you add some acid to the oceans, the total amount of carbon forms (DIC: CO2 + bi + carbonates) would decrease because of the loss of CO2, while we see an increase of DIC with decreasing pH.
That proves that CO2 is pressed into the oceans, not the other way out…
Simply add some vinegar to a solution of (baking) soda and weigh both containers before and after the mixing…

Ferdinand says “The only point where Bart could be right is if the natural carbon cycle increased a 3-fold together with the human emissions: then and only then the natural cycle could dwarf the human emissions.”
Natural sources and sinks are ~96% of the carbon cycle. Natural sinks would only have to expand by ~4% to accommodate all man-made CO2. Multiple papers show from satellite measurements that the Earth has “greened” 11-20% over the past couple decades, thus the natural sinks could have expanded ~11-19%, considerably more than the 4% man-made sources. No 300% increase in the carbon cycle required as you claim.
Single graph shows T controls CO2 on short timescales:
http://hockeyschtick.blogspot.com/2013/01/single-graph-demonstrates-man-made-co2.html

Hockey Schtick says:
July 29, 2014 at 4:38 pm
Natural sinks would only have to expand by ~4% to accommodate all man-made CO2.
Completely right, but they didn’t do that over the past 55 years:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em2.jpg
thus the natural sinks could have expanded ~11-19%, considerably more than the 4% man-made sources.
The greening of the planet is a fact, but that is only for ~1 GtC/year of the 9 GtC/year human emissions. That is the net result of the increased cycle. Again, the height of the natural cycle is not of interest, the net source/sink result after a full cycle is what is of interest:
http://www.sciencemag.org/content/287/5462/2467.short
and
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
The 300% is only of mathematical interest: human emissions increased a threefold over the past 50 years or so. As plants and oceans don’t make any differentiation between human and natural CO2 (except a slight one in isotopes), if not humans are responsible for the increase of CO2 in the atmosphere, then the natural CO2 cycle should have increased a threefold too, to build enough resistance in the (then theoretically very fast accommodating) sinks so that they can’t remove the extra CO2 flux in short term, but still remove near all of human emissions.
But there is not the slightest indication that that happened: not in the residence time, not in the 14C/12C ratio, not in the 13C/12C ratio, not in the oxygen changes,…

DesertYote says:
July 29, 2014 at 4:41 pm
From -20 to +40 C, the CO2 produced by eukaryote metabolism is directly related to temperature. Don’t ask me to quote a bogus study. Referencing studies is NOT science. Do the experiment for yourself. It easy grade school stuff. Use yeast.
Sometimes simple sums and subtractions are of more importance than fancy linear equations…
The eukaryotes only produce CO2 that was first captured out of the atmosphere by plants in the form of sugars and other stuff. Thus that is part of the natural cycle and doesn’t add any extra CO2 to the atmosphere, as long as plants capture more CO2 out of the atmosphere than the rest of the biosphere can eat/break down/oxidize again.
Which is the case, based on the net oxygen production by the biosphere.
Thus again, that humans emit only 4% of the natural emissions is of no interest at all, as nature captures 102% of the natural emissions back each year… Which means that the net natural contribution to the atmospheric increase is zero, nada, nul,…

Ferdinand said, “As long as there is an airborne fraction, humans are responsible…”
So, *nothing* else is changing in the carbon balance: no volcanoes erupting, no algae blooms blooming, etc.? Gaia is running a controlled experiment I guess? Including any sources/sinks that we have yet to characterize?
Do we even know if we’re in a regime where the D.E.s can be treated as approximately linear?
The problem is far more subtle than the crude lumped averages in the table can possibly illuminate. The conclusion that humans are *solely* responsible for the airborne fraction is unwarranted.

Ferdinand Engelbeen says:
July 29, 2014 at 5:26 pm
DesertYote says:
July 29, 2014 at 4:41 pm
###
Your attempt to model the carbon cycle using naive linear equations is a big fail. The rate at which CO2 is “sequestered” is directly related to the concentration of CO2. The rate at which CO2 is released is directly related to temperature. You can not model a system like this without differential equations. The overestimated rate of anthropogenic CO2 production is well within the measurement uncertainty of vastly underestimated rate of “natural” CO2, and much smaller then the natural variability. What we have here is a naturally stabilizing system with a great deal of negative feed back that totally swamps out mans insignificant contributions. The history of the Earth demonstrates this quite well, else life would have been destroyed when the Deccan Traps were created. Get real. Do some real math for a change. What are planning on doing next, try modeling the solar system using epicycles?
Your “We don’t need no steenking diff eq” stance just makes you look foolish to those of us with real systems engineering experience.

Ferdinand Engelbeen says:
July 29, 2014 at 5:26 pm
“Thus again, that humans emit only 4% of the natural emissions is of no interest at all, as nature captures 102% of the natural emissions back each year…”
Once again, a complete detachment from the way feedback systems work.
JJ says:
July 29, 2014 at 10:47 pm
“In fact, they could be much larger than half the anthro pipe, perhaps several times that size.”
Bingo! In fact, if one takes it as given that it could be anywhere from half to many multiples, the overwhelmingly greater share of possibilities obviously tends toward the latter.
DesertYote says:
July 29, 2014 at 11:25 pm
Yes. It is a fundamental misconception to try to model this dynamic system as though it were a problem in basic accounting.
It is, again, a detachment from the way feedback systems work. The inflow and outflow are not static, unchanging quantities. The outflow expands in reaction to the inflow.
This static point of view is one of a magical world, in which an equilibrium between natural inflow and outflow simply happened, and stayed that way just because one side wanted to play nice with the other.
That is not how an equilibrium is established in nature in this universe. If there is no push-back from either side, then random fluctuations create a drift, like Brownian motion of a particle suspended in a fluid. Scientifically speaking, the notion that there was a rock solid equilibrium in existence for millennia when there were no opposing forces keeping it there is farcical.
Given the powerful opposing forces necessary to produce such a tight equilibrium, it must be presumed that nature can shrug off our puny inputs with hardly any notice. It is very obvious that nature is in control of the atmospheric CO2 balance on this planet. It never ceases to amaze me how people will rationalize away something which is right before their noses like this. Someday, people will look back on this silly idea that humans control the planet’s CO2 like we now do at leechcraft, phlogiston, or phrenology.

This number shows emissions and absorptions. In an equilibrium model, emissions and absorption would be equal. They are not. The difference (and a bit more) is due to extra CO2 from fossil fuel and land-use change. On this, at least, I’m glad to see you on the same side as the climate-change people.

Hockey Schtick says:
July 29, 2014 at 6:05 pm
Where is the data to back up this assertion, and what assumptions are made?
The net uptake of the biosphere is based on the oxygen balance: fuel consumption is known with reasonable accuracy (if anything wrong, probably underestimated). CO2 emissions and oxygen use for the different fuels can be calculated and the oxygen decrease in the atmosphere can be measured (be it at the edge of analytical possibilities). That shows that since the 1990’s some less oxygen is used than calculated. The difference is what the biosphere as a whole (land + ocean plants, bacteria, molds, insects, animals, humans) has produced (or used) by (plant) uptake or (plant/others) decay/food/feed/burning. This makes it easy to make the distinction between simple ocean release/uptake and the biosphere release/uptake as for the oceans no oxygen is involved (except for its solubility in seawater). Another way is to look at the δ13C balance, which is far more pronounced – and opposite – than the ocean influence. Both methods gives a similar net uptake by the biosphere:
http://www.sciencemag.org/content/287/5462/2467.short and
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
Natural sinks would have only had to increase a mere 4% to accommodate all man-made CO2, and the error bars on natural sources and sinks are large, as well as on land-use changes.
It seems quite difficult to understand the difference between an increased cycle and the net result of a cycle.
If we take the ~1.5 GtC/year extra uptake of the biosphere for granted, that gives an increase in total bio carbon mass of ~30 GtC over the past two decades. That is about 5% in total mass.
Does that increase the seasonal cycle? Maybe somewhat, but not in the tropics: the decay rate and growth rate there is near equal, except during El Niño’s (drought, heat) and Pinatubo’s. Thus the difference should be in the extra-tropic (mainly NH) forests. That should be visible in the seasonal cycle, because the NH seasonal cycle is dominated by the NH forests.
I haven’t looked at that in detail, but there are signs that the seasonal cycle increased over time.
But again, and increase in seasonal cycle doesn’t influence the net result of the cycle: more growth is accompanied by more decay, as most debris is from one-year leaves…
While the error bars of the natural cycle are huge, the net result shows a remarkably modest variation: not more than +/- 1 ppmv (2 GtC) from year to year:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em2.jpg
including huge influences from the 1992 Pinatubo and 1998 El Niño.
That is less than halve the human emissions and less than 3% of the estimated fluxes. But take into account that seasonal ocean and biosphere fluxes are opposite to each other with the temperature change.
Land use changes only add to the human emissions…

When I once pointed out how Nick Stokes had misrepresented an article written by Roy Spencer, rather than admit the completely black and white mistake, Stokes obfuscated and misdirected in shameless fashion. What a vast gulf exists between those of intellectual merit who admit mistakes, and the hacks.