Does CO2 really drive global warming?

Chemical Innovation ^ | May 2001 | Robert H. Essenhigh

[kidd]

Does CO2 really drive global warming?

I don’t believe that it does.

To the contrary, if you apply the IFF test—if-and-only-if or necessary-and-sufficient—the outcome would appear to be exactly the reverse. Rather than the rising levels of carbon dioxide driving up the temperature, the logical conclusion is that it is the rising temperature that is driving up the CO2 level. Of course, this raises a raft of questions, but they are all answerable. What is particularly critical is distinguishing between the observed phenomenon, or the “what”, from the governing mechanism, or the “why”. Confusion between these two would appear to be the source of much of the noise in the global warming debate.

In applying the IFF test, we can start with the clear correlation between the global CO2 profile and the corresponding temperature signature. There is now in the literature the report of a 400,000-year sequence clearly showing, as a phenomenon, that they go up—and down—together (1). The correlation is clear and accepted. But the causation, the mechanism, is something else: Which is driving which?

Logically, there are four possible explanations, but only two need serious consideration, unless they both fail.

Case 1: CO2 drives the temperature, as is currently most frequently asserted; and

Case 2: Temperature drives the level of CO2.

Both appear at first to be possible, but both then generate crucial origin and supplementary questions. For Case 1, the origin question is: What is the independent source of CO2 that drives the CO2 level both up and down, and which in turn, somehow, is presumed to drive the temperature up and down? For Case 2, it is: What drives the temperature, and if this then drives the CO2, where does the CO2 come from? For Case 2, the questions are answerable; but for Case 1, they are not.

Consider Case 2. This directly introduces global warming behavior. Is global warming, as a separate and independent phenomenon, in progress? The answer, as I heard it in geology class 50 years ago, was “yes”, and I have seen nothing since then to contradict that position. To the contrary, as further support, there is now documentation (that was only fragmentary 50 years ago) of an 850,000-year global-temperature sequence, showing that the temperature is oscillating with a period of 100,000 years, and with an amplitude that has risen, in that time, from about 5 °F at the start to about 10 °F “today” (meaning the latest 100,000-year period) (2). We are currently in a rise that started 25,000 years ago and, reasonably, can be expected to peak “very shortly”.

On the shorter timescales of 1000 years and 100 years, further temperature oscillations can be seen, but of much smaller amplitude, down to 1 and 0.5 °F in those two cases. Nevertheless, the overall trend is clearly up, even through the Little Ice Age (~1350–1900) following the Medieval Warm Period. So the global warming phenomenon is here, with a very long history, and we are in it. But what is the driver?

Arctic Ocean model

The postulated driver, or mechanism, developed some 30 years ago to account for the “million-year” temperature oscillations, is best known as the “Arctic Ocean” model (2). According to this model, the temperature variations are driven by an oscillating ice cap in the northern polar regions. The crucial element in the conceptual formulation of this mechanism was the realization that such a massive ice cap could not have developed, and then continued to expand through that development, unless there was a major source of moisture close by to supply, maintain, and extend the cap. The only possible moisture source was then identified as the Arctic Ocean, which, therefore, had to be open—not frozen over—during the development of the ice ages. It then closed again, interrupting the moisture supply by freezing over.

So the model we now have is that if the Arctic Ocean is frozen over, as is the case today, the existing ice cap is not being replenished and must shrink, as it is doing today. As it does so, the Earth can absorb more of the Sun’s radiation and therefore will heat up—global warming—as it is doing today, so long as the Arctic Ocean is closed. When it is warm enough for the ocean to open, which oceanographic (and media) reports say is evidently happening right now, then the ice cap can begin to re-form.

As it expands, the ice increasingly reflects the incoming (shorter-wave) radiation from the sun, so that the atmosphere cools at first. But then, the expanding ice cap reduces the radiative (longer-wave) loss from the Earth, acting as an insulator, so that the Earth below cools more slowly and can keep the ocean open as the ice cap expands. This generates “out-of-sync” oscillations between atmosphere and Earth. The Arctic Ocean “trip” behavior at the temperature extremes, allowing essentially discontinuous change in direction of the temperature, is identified as a bifurcation system with potential for analysis as such. The suggested trip times for the change are interesting: They were originally estimated at about 500 years, then reduced to 50 years and, most recently, down to 5 years (2). So, if the ocean is opening right now, we could possibly start to see the temperature reversal under way in about 10 years.

What we have here is a sufficient mechanistic explanation for the dominant temperature fluctuations and, particularly, for the current global warming rise—without the need for CO2 as a driver. Given that pattern, the observed CO2 variations then follow, as a driven outcome, mainly as the result of change in the dynamic equilibrium between the CO2 concentration in the atmosphere and its solution in the sea. The numbers are instructive. In 1995, the Intergovernmental Panel on Climate Change (IPCC) data on the carbon balance showed ~90 gigatons (Gt) of carbon in annual quasi-equilibrium exchange between sea and atmosphere, and an additional 60-Gt exchange between vegetation and atmosphere, giving a total of ~150 Gt (3). This interpretation of the sea as the major source is also in line with the famous Mauna Loa CO2 profile for the past 40 years, which shows the consistent season-dependent variation of 5–6 ppm, up and down, throughout the year—when the average global rise is only 1 ppm/year.

In the literature, this oscillation is attributed to seasonal growing behavior on the “mainland” (4), which is mostly China, >2000 mi away, but no such profile with that amplitude is known to have been reported at any mainland location. Also, the amplitude would have to fall because of turbulent diffusive exchange during transport over the 2000 mi from the mainland to Hawaii, but again there is lack of evidence for such behavior. The fluctuation can, however, be explained simply from study of solution equilibria of CO2 in water as due to emission of CO2 from and return to the sea around Hawaii governed by a ±10 °F seasonal variation in the sea temperature.

Impact of industrialization

The next matter is the impact of fossil fuel combustion. Returning to the IPCC data and putting a rational variation as noise of ~5 Gt on those numbers, this float is on the order of the additional—almost trivial (<5%)—annual contribution of 5–6 Gt from combustion of fossil fuels. This means that fossil fuel combustion cannot be expected to have any significant influence on the system unless, to introduce the next point of focus, the radiative balance is at some extreme or bifurcation point that can be tripped by “small” concentration changes in the radiation-absorbing–emitting gases in the atmosphere. Can that include CO2?

This now starts to address the necessity or “only-if” elements of the problem. The question focuses on whether CO2 in the atmosphere can be a dominant, or “only-if” radiative-balance gas, and the answer to that is rather clearly “no”. The detailed support for that statement takes the argument into some largely esoteric areas of radiative behavior, including the analytical solution of the Schuster–Schwarzschild Integral Equation of Transfer that governs radiative exchange (5–7), but the outcome is clear.

The central point is that the major absorbing gas in the atmosphere is water, not CO2, and although CO2 is the only other significant atmospheric absorbing gas, it is still only a minor contributor because of its relatively low concentration. The radiative absorption “cross sections” for water and CO2 are so similar that their relative influence depends primarily on their relative concentrations. Indeed, although water actually absorbs more strongly, for many engineering calculations the concentrations of the two gases are added, and the mixture is treated as a single gas.

In the atmosphere, the molar concentration of CO2 is in the range of 350–400 ppm. Water, on the other hand, has a very large variation but, using the “60/60” (60% relative humidity [RH] at 60 °F) value as an average, then from the American Society of Heating, Refrigerating and Air-Conditioning Engineers standard psychrometric chart, the weight ratio of water to (dry) air is ~0.0065, or roughly 10,500 ppm. Compared with CO2, this puts water, on average, at 25–30 times the (molar) concentration of the CO2, but it can range from a 1:1 ratio to >100:1.

Even closer focus on water is given by solution of the Schuster–Schwarzschild equation applied to the U.S. Standard Atmosphere profiles for the variation of temperature, pressure, and air density with elevation (8). The results show that the average absorption coefficient obtained for the atmosphere closely corresponds to that for the 5.6–7.6-µm water radiation band, when water is in the concentration range 60–80% RH—on target for atmospheric conditions. The absorption coefficient is 1–2 orders of magnitude higher than the coefficient values for the CO2 bands at a concentration of 400 ppm. This would seem to eliminate CO2 and thus provide closure to that argument.

This overall position can be summarized by saying that water accounts, on average, for >95% of the radiative absorption. And, because of the variation in the absorption due to water variation, anything future increases in CO2 might do, water will already have done. The common objection to this argument is that the wide fluctuations in water concentration make an averaging (for some reason) impermissible. Yet such averaging is applied without objection to global temperatures, when the actual temperature variation across the Earth from poles to equator is roughly –100 to +100 °F, and a change on the average of ±1 °F is considered major and significant. If this averaging procedure can be applied to the atmospheric temperature, it can be applied to the atmospheric water content; and if it is denied for water, it must, likewise, be denied for temperature—in that case we don’t have an identified problem!

What the evidence shows

So what we have on the best current evidence is that

global temperatures are currently rising;

the rise is part of a nearly million-year oscillation with the current rise beginning some 25,000 years ago;

the “trip” or bifurcation behavior at the temperature extremes is attributable to the “opening” and “closing” of the Arctic Ocean;

there is no need to invoke CO2 as the source of the current temperature rise;

the dominant source and sink for CO2 are the oceans, accounting for about two-thirds of the exchange, with vegetation as the major secondary source and sink;

if CO2 were the temperature–oscillation source, no mechanism—other than the separately driven temperature (which would then be a circular argument)—has been proposed to account independently for the CO2 rise and fall over a 400,000-year period;

the CO2 contribution to the atmosphere from combustion is within the statistical noise of the major sea and vegetation exchanges, so a priori, it cannot be expected to be statistically significant;

water—as a gas, not a condensate or cloud—is the major radiative absorbing–emitting gas (averaging 95%) in the atmosphere, and not CO2;

determination of the radiation absorption coefficients identifies water as the primary absorber in the 5.6–7.6-µm water band in the 60–80% RH range; and

the absorption coefficients for the CO2 bands at a concentration of 400 ppm are 1 to 2 orders of magnitude too small to be significant even if the CO2 concentrations were doubled.

The outcome is that the conclusions of advocates of the CO2-driver theory are evidently back to front: It’s the temperature that is driving the CO2. If there are flaws in these propositions, I’m listening; but if there are objections, let’s have them with the numbers.

References

1. Sigman, M.; Boyle, E. A. Nature 2000, 407, 859–869.
2. Calder, N. The Weather Machine; Viking Press: New York, 1974.
3. Intergovernmental Panel on Climate Change. Climate Change 1995: The Science of Climate Change; Houghton, J. T., Meira Filho, L. G., Callender, B. A., Harris, N., Kattenberg, A., Maskell, K., Eds.; Cam bridge University Press: Cambridge, U.K., 1996.
4. Hileman, B. Chem. Eng. News 1992, 70 (17), 7–19.
5. Schuster, A. Astrophysics J. 1905, 21, 1–22.
6. Schwarzschild, K. Gesell. Wiss. Gottingen; Nachr. Math.–Phys. Klasse 1906, 41.
7. Schwarzschild, K. Berliner Ber. Math. Phys. Klasse 1914, 1183.
8. Essenhigh, R. H. On Radiative Transfer in Solids. American Institute of Aeronautics and Astronautics Thermophysics Specialist Conference, New Orleans, April 17–20, 1967; Paper 67-287; American Institute of Aeronautics and Astronautics: Reston, VA, 1967.

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Robert H. Essenhigh is the E. G. Bailey Professor of Energy Conversion in the Department of Mechanical Engineering, Ohio State University, 206 W. 18th Ave., Columbus, OH 43210; 614-292-0403; essenhigh.1@osu.edu.

[kidd]

My friend, our Father loves us so much that He gave us His only son, Jesus Christ, so that we may be freed from sin. In light of that, all discussions related to the age of the earth are quite minor (and are also only a minor part of the article). I respect your position, but it is better suited for a theological thread.

I respectfully ask you and all future posters to avoid that tangential thread and instead discuss the merits or faults with the author's thesis.

[aspiring.hillbilly]

There is at least 8,500,000,000,000,000 cubic meters of air in the earth's atmosphere. There is no way that incremental CO2 produced by human activities can in any way cause the atmosphere to change in any measureable way. Its just too vast; none of this scientific bullhocky takes this figure into account. That would cause instant invalidation of these alleged theories.

[biblewonk]

We are currently in a rise that started 25,000 years ago and, reasonably, can be expected to peak “very shortly”.

I respectfully submit that the age of the earth is very important to this discussion. The "science" that suggests an evolutionary cosmology is what I reject. I'd like to have someone quantify the thermal effects of a cubic yard of atmosphere with 50 vs 70 ppm of CO2 with respect to solar heating and heat retention. I have yet to see any discussion of this topic contain that though I admit that I didn't read this very close.

Then if it were to be proven that the 20 ppm delta can increase the temperature by a degree or 2, what does that do to vegitation which tends to eat CO2. It sure seems like it may be a system with checks and balances built in.

[kidd]

One of the authors arguments is related radioactive isotope dating (which you may disagree with). However, you can still reject that argument and are still left with other strong arguments.

He presents an argument that the effects of water vapor completely overwelm any effect of CO2.

He also presents arguments related to the relatively miniscule contribution that humans have in the carbon cycle.

Additionally, he argues that the seasonal variation observed in CO2 levels is better explained by ocean outgassing than by plant use. CO2 turnover is too fast to allow human emmisions to account for the atmospheric increase.

[nhbob1]

natural venting of a methane pocket

Sounds like my house after a meal at the local Mexican restaurant. :)

[snooker]

Here is an interesting reasearch summary which shows how you can take the last 1000 years of data and distort what is happening.
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v407/n6806/full/407859a0_fs.html

As you can tell, the earth has been there and done that already.

snooker

[EdZ]

I was not planning on debating global warming in this forum. My first two threads were limited only to establishing the fact that burning fossil fuels has indeed caused an increase in the concentration of greenhouse gases in the atmosphere. But due to popular demand I will critique the above article by Robert Essenhigh.

His article relies strongly on the “Arctic Ocean Model” explanation of the ice ages, which he cites from the book “The Weather Machine,” based on a 2 hour BBC television program from 1974. The book presents this as one of many theories explaining the ice ages. On page 129 the book says that the Arctic Ocean Model is “weak when applied in detail in the theory of a ‘warm Arctic’, which clears the northern seas of ice so that they can produce plenty of snow on the surrounding lands. North-Eastern Siberia and northern Alaska carry relatively little ice during an ice age; if the Arctic were a major source of snow they would have plenty.”

The book then goes on to explain more theories that do not depend on external radiative forcings, and finds these equally objectionable. The author finds the radiative forcing theories to be more plausible, including variations in sunlight caused by the Milankovich cycles and solar cycles. Another radiative forcing theory supported by the book is that changes in CO2 concentrations can change global temperatures, while also pointing out that global warming can cause carbon dioxide to be released from the oceans.

This brings us to another point from Essenhigh’s essay, which seems to suggest that the causal link between CO2 and global temperatures is an either/or proposition. The notion that climate change has a single cause is a logical fallacy. The current mainstream view is that CO2 increases global temperatures, AND increasing global temperatures increases CO2. “The Weather Machine” speculates that this positive feedback mechanism could generate a “runaway greenhouse effect,” similar to that on the planet Venus. The more modern view is that we could never get a greenhouse effect as bad as Venus, but that CO2 does play a role in climate change.
Another of Essenhigh’s points that deserves a harsh rebuke is his statement that, “The CO2 contribution to the atmosphere from combustion is within the statistical noise of the major sea and vegetation exchanges, so a priori, it cannot be expected to be statistically significant.” He is referring to the fact that each year’s contribution from fossil fuel burning is very small, but ignores that fact that it accumulates over time. His main reference, “The Weather Machine,” presents the famous Mauna Loa data on page 78, and points out that by 1974 CO2 had increased 10% since the beginning of the industrial revolution, mainly as a result of burning fossil fuels. Looking in more modern references, you will find that the figure for this year is 30%, and the figure for 2060 is 100% in the “business as usual” scenario.
Finally, everyone knows that a column of air will absorb an equal amount of infrared radiation if you double the concentration of CO2. But the point is that doubling CO2 changes the distribution of temperature as a function of height, so that heat emanating from the Earth is trapped closer to the surface, while the air gets cooler at higher elevations.

Notice that Essenhigh does not provide any numbers or estimates of how he thinks doubling CO2 would influence surface temperatures. Is it 0.0 degrees C, 1.5 degrees C, 3 to 5 degrees C? Everyone knows that water vapor is the most important natural greenhouse gas in the atmosphere. Estimates for climate sensitivity from modern climate models are scientist’s best efforts to find out how much influence our pollution will have on the future climate.

Since he reaches back to references from 1905 in his discussion of the relative importance of water versus carbon dioxide, I doubt that he is revealing anything that the climate modelers don’t know.

Finally, notice the tag on the upper right hand side of the article saying “VIEW”. This means that the article in an OPINION piece. I went to this article’s parent webpage, www.acs.org and searched for “global warming” and the first hit was “NEWS of the week – Science Affirms Global Warming… NRC panel report that impacts could be extremely adverse by 2100.” Another of the top hits was “Today’s Headlines – Humans Causing Climate Change … Bush Administration accepts global warming and its impacts as inevitable.” It is nice, however that someone posted something from the American Chemical Society, the world’s largest scientific society, rather than from an organization with an obvious political affiliation.

Thank you for the discussions, I hope this hour of my time will be appreciated. As I said before, I was not planning on arguing global warming on this website, I only wanted to present the greenhouse gas information. Online discussions of complex subjects such as global warming do not work very well unless you follow a “book club” model, i.e. read two books with opposing viewpoints and then debate from that common knowledge base. By the way, I would recommend “Global Warming” by John Houghton, chief climatologist for the UK. Probably the best opposing viewpoint book would be “The Skeptical Environmentalist” by Bjorn Lomborg. (I would encourage you to read both books.) Checking the scientific journals and expert panel reports is also a good way to learn about the current state of environmental science.

[EdZ]

I also meant to point out that everyone knows that water vapor is the most important natural greenhouse gas in the atmosphere. The human contribution to radiative forcing is small in comparison, yet a doubling of atmospheric CO2 is likely to produce a warming of 2.5 to 8 degrees C according to the Bush Administration.

[Monti Cello]

This article strikes me as a hack job. The author makes some interesting points, but only after completely discrediting himself. If this is truly published in a reputable science journal, it makes me wonder if there is indeed a political agenda (not the author's) in play.

Trying to explain CO2 levels by temperature change is ludicrous on its face -- the ice core record of CO2 shows that industrialization is the dominant cause in recent centuries, and completely unlike other interglacial periods. Spending paragraphs on explaining century-scale warming with a million-year cycle is also pointless.

The seasonal cycle at Mauna Loa is normally explained by terrestrial biomass drawdown in Northern Hemisphere summer. The author tries to invoke temperature-dependent ocean chemistry, but CO2 is more soluble in water at low temperatures -- which would produce peaks, not troughs in summer at Mauna Loa.

[EdZ]

Being new to web forums, I am surprised that this post got BUMPED down to page 5 after only a few hours. I guess a lot of people post on this site. Please forgive me as I figure out how this forum works.

Monti Cello, what do you think about my responses to the article's "interesting points?"

By the way, could anyone tell me how to post graphics? I wanted to post the famous Mauna Loa CO2 data for the masses of people here who cannot accept the reality that burning fossil fuels does indeed increase the concentration of CO2 in the atmosphere.

A preview of my next post: Hypothetically, what would happen to the CO2 in the atmophere if we stopped burning fossil fuels overnight?

[farmfriend]

hoax ping

[farmfriend]

Storm Front

Flawed Metaphor

Taken by Storm also takes on the greenhouse metaphor. The so-called greenhouse effect does not work like a greenhouse. Incoming solar radiation adds energy to the Earth's climate. To restore radiative balance, the energy must be transported back to space in roughly the same amounts in which it arrived. The energy is transported via two processes - infrared radiation (heat transfer) and fluid dynamics (turbulence). "When you add up the net amount of energy flow away from the surface by pure (infrared) radiation, it turns out to be roughly the same as that carried away by wind, air movements and evaporation," says Essex.

This is a really good article for anyone studying the global warming hoax.

[farmfriend]

You really need to check out the bump list in post #19. You should read those articles. You won't convince anyone here that you are right otherwise.

[farmfriend]

By the way, could anyone tell me how to post graphics?

HTML Sandbox

[E.G.C.]

BTTT!!!!!

[Monti Cello]

I thought your points were well-reasoned, and you seem to have a better grasp of the issue than the author of the article.

The best point in the article in my view is that the CO2 forcing is just a very minor component of total greenhouse forcing. If you look at 20th century temperature variations, a signature of decadal climate variability over the Pacific seems to be present -- there is little reason to assume that water vapor forcing has been stable over this period.

Welcome to FR. Posts do get scrolled here quickly -- one thing folks do is use use the 'Latest Posts' browser instead of 'Latest Threads' to see what's actively being discussed -- easier to get to older posts that way. This also drives the FR technique of 'bumping' posts by replying to them so that they rise back to the top of the Latests Posts list.

[Monti Cello]

Here ya go:

[EdZ]

Initially, I posted here to discuss the increasing concentrations of greenhouse gases in the atmosphere, not to discuss global warming. In posting a critique of the above article, I am just trying to be a nice guy in responding to a request, and I am not determined to convince anyone of anything.

Before I registered here I have already saw most of those articles that are posted here. I have also gone to the library to read from peer reviewed scientific journals and from magazines such as Scientific American, and from expert panel reports from the National Academy of Sciences, the IPCC, and the Bush Administration.

In response to you discussion of the book Taken by Storm: think carefully, do air currents and evaporation transport heat all they way from the Earth's surface into the vacuum of empty space? Do the climate models of global warming already incorporate heat transfer by evaporation and air and ocean currents?

But I am reluctant to debate climate modelling due to a lack of time. Apparently you recognize that concentrations of carbon dioxide, methane, and other greenhouse gases are rising, primarily due to burning fossil fuels. Since you are a Christian (and I am a Christian too.), you must be interested in the truth, so you might want to discuss the rising GHG concentrations with the other forum members who deny that this is happening.

You could also check out what some of the world's oldest and largest scientific societies have to say about greenhouse gases and climate change, at www.acs.org, http://www.nationalacademies.org, www.aip.org, www.agu.org. But I also think searching the web is not substitute for going to the library. Good luck.

[Barry Bright]

If I'm not terribly mistaken the national academies, like a lot of these "official organizations" or ngos or whatever that the eco-commies constantly cite are little more than Marxist front groups. Yes govt. agencies can be Marxist front groups, aka, the BATF. Look at who they go to for “advice” on us “extremists,” the ADL. The chemical society or whatever can be expected to protect its interests as well. The corporations fund the eco commies to the tune of hundreds of millions. I wonder why?

Adolf Hitler said it best: "The truth is the best propaganda." Even if "global warming" is the threat that the eco commies constantly tell us it is, and I don't think so even though I'm not a "scientist," they are still using it to forward their evil agenda, a global “redistribution of wealth” ala Karl Marx.

Guns are weapons used to kill. That is the truth. That is the propaganda the Ameri-commies use to scare the sheeple in the attempt to disarm us so that when the time comes, and it likely will, we won’t be able to physically fight back against the fulfillment of their evil agenda. .

The point is what are their goals? Why do they throw this in our face constantly? Do they really "care" about all of us?

I suggest you go to the wildlands project website for starters:

http://www.wildlandsproject.org/

and the site that explains their goals:

http://www.wildlandsprojectrevealed.org/

And some more links: http://www.willowtown.com/freekentucky/links/environment.htm

As far as Dubya’s policy goes, he and the rest of the Republicrats still have a lot to learn, or they are exceedingly intellectually dishonest. Take your pick. Dubya’s recent statement, via his press spokesman or whomever, on the “assault weapons ban,” that he would support its reup in 2004, is a fine example.

Go to google and type in “worldwide redistribution of wealth” and see what you get.

So many are missing the point entirely by playing the game and engaging in the “debate” by our enemies’ rules. It’s time to end that, or die. Our founders said “join or die.” We should listen.

Barry Bright
Freekentucky.com

Anyone who wishes to personally respond to me please use my email address as I rarely come to this site. bbright@freekentucky.com

[biblewonk]

He presents an argument that the effects of water vapor completely overwelm any effect of CO2.

I've heard this too. CO2 is 50-70 ppm while water vapor is thousands of parts per million. Usually when I hear this I hear a phrase like "also a greenhouse gas". I'm into physics and I want to hear quantities in actual scientific terms. How much heat does what percentage of greenhouse gas hold. They never quantify that which makes the whole discussion sound more like a wifes fable than science to me.