The facts about Global Warming (discussion)

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Mon, 02/22/2010 - 03:23

jason

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The facts about Global Warming (discussion)

So I wrote an article on what I consider to be the facts about climate change. This might be a nice article to start off the forum :)

Here is the article: http://www.warmdebate.com/blog/facts-about-global-warming

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Sun, 10/24/2010 - 16:54

sentient

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First we need to revisit both Greenland and Antarctica. Antarctica is virtually a desert with annual average snowfalls measured in inches whereas Greenland's are measured in tens of feet. Ice tends to get only so thick before becoming unstable, with the nominal depth at either pole roughly 4 kilometers, of some 2.5 miles. This has to do with the P/T point for water. As an example ice skating is only possible in a fairly narrow range of temperature below freezing due to the weight of a person's body being distributed over the relatively small surface area of the blades which pushes the boundary and melts the ice below the blade (with a hat tip to the friction modulus as well). At temperatures which range far below the freezing point (typically -80C +/-), the P/T boundary for melting or reaching plasticity this point is reached at the aforementioned nominal depth of roughly 4km. Lake Vostok is a good example and the original Vostok drilling project was terminated before reaching the liquid lake beneath the icecap in order to prevent possible contamination of the water body. Since the late 90's, carefully prepared penetrations have indeed entered the waters of the trapped lake.

But the real point here is that with far less snowfall, ice has accumulated from much further back in time at most Antarctic drilling locations albeit at much coarser resolution than in Greenland. Dome Concordia cores record climate back between 650k-800k years, depending upon whose research you are referring to. The 800kyr point getting us close to MIS-19, whereas the best Greenland cores get us back somewhere within MIS-5 but does not record Termination 2, or the transition from the Illinoian glacial to the Eemian interglacial, presumably because the Greenland ice sheet had melted completely or mostly completely away during the last interglacial.

If the melting of the Greenland ice sheet occurred due to CO2 levels, then it did so at concentrations far below present levels (perhaps ominous?), and it did so very early in the interglacial not towards the end, otherwise we would not have ice that goes almost through MIS-5 there. The Eemian interglacial is thought to have lasted something on the order of 10-12k years, and we are at roughly the 11,500 year point now in the Holocene. As I mentioned in my first post, MIS-5 is orbitally not as good a match as MIS-11 or MIS-19. CO2 concentrations during MIS-5 were not radically different to those of pre-industrial Holocene times, and since we are able to core through Holocene accumulations there, reaching early MIS-5 age ice, then it obviously did not melt away even at the Holocene Climate Optimum (roughly 6-7kyrs ago).

And a small correction, neither I nor Sole, Turiel and Llebot alluded that the period from 20-60kyrs resembles our current class of temperature cycles. They (and I) were referring to a portion (the deepest part) of time during the last glacial, the Wisconsin in North American nomenclature. The resolution of the EPICA cores over this period is far coarser than that from GISP2 in Greenland, so one can see changes in temperature (oxygen and deuterium isotopes) and CO2 on decadal timescales as opposed to millenial, possibly centennial scales in Antarctica. What they were referring to was comparing CO2 to their ("our" as in authors) temperature cycles. I would read the entire paper, it is available online through Science Direct.

Getting back on track, one can ascertain from the literature that the range of estimates for sea level during the Eemian go from 0 to +52 meters, with my gut feeling being that the majority opinion might be closer to +6 meters with Rohling et al 2008 (Nature Geoscience, Vol 1 January 2008) providing evidence for a MIS-5e highstand of +20 meters.

(I was going to post the graphic, is this possible from my computer? These are not stored on some website)

MIS-11 scored a +21.3 meter highstand, with a sustained stillstand in the range of +21 meters (Olson and Hearty Quaternary Science Reviews 28 (2009) 271–285).

(again, I was going to put up the graphic from the paper but this does not seem possible by transfer from my computer)

The upshot here being to pay respect to signal to noise ratio (SNR). Regardless of one's position relative to CO2 forcing, be it natural or anthropogenic, in order to recognize something as anomalous it must not only be larger (rule of thumb is twice background) and discernible as to cause. With a background populated with +21, +20, or even +6 meter highstands and stillstands, cognition of an anthropogenic "signal", such as the IPCC AR4 (2007) worst case of +0.59 meters by 2100 would not be possible in terms of it being anomalous. Even at the arguably median natural value of +6 meters attained at MIS-5e, the AR4 worst case estimate comes in at 10% not the 200% of background normally considered to be an anomaly. Keeping in mind that MIS-5 is considered an inferior orbital analog to MIS-1 (the Holocene) with MIS-11 generally recognized to be the better orbital analog. Compared with a +20 meter highstand in MIS-11, +0.59 meters would be merely a slight perturbation.

If a single variable such as CO2 is taken to be the dominant causative variable of the MIS-11 and MIS-5 highstands, and anthropogenic emissions of CO2 the causative agent of a Holocene highstand which has not yet happened, then the CO2 problem is probably worse than we thought. Imagine applying any single or combination of CO2 reducing strategies, including geoengineering to quash the anthropogenic IPCC AR4 worst case signal. Given that is has happened several times before (there were at least 3 highstands in MIS-5 greater than present, and at least 2 in MIS-11), we might very well watch sea level (and presumably global temperatures) soar 10 to 33 times the IPCC AR4 prognosticated level anyway. To quash this amount of CO2 forcing we would have to mount an effort against natural causation orders of magnitude greater than what has so far been proposed.

Which brings us to consideration if "IPCC theory". Most scientists would regard a theory as just below a scientific "law". In science a theory is a hypothesis which is supported by significant observational data such that it stands fairly solidly on its foundation. In the case of the IPCC, it has long been suspected that "science" is a component, but there are so many observational anomalies on many tenets that the IPCC efforts are easily shown to be highly problematic. The IPCC is supposed to be providing a "state of the science" summation regarding anthropogenic forcings, however there are far too many instances of the "state of the science" not including observational studies which do not support the AGW theory for its results to be considered authoritative. And that is not the view of an AGW skeptic, it is the hard, cold view of a practicing earth scientist all too familiar with this sort of scientific subversion. I spend about half of my professional time picking apart the opposition's "scientific arguments" for environmental torts often culminating in testimony as an expert witness. So this kind of misprision of science is by no means unknown to me, nor is it in any way uncommon. The Climategate emails would have been a godsend for any opposing counsel's case, regardless of where one's own proclivities lie.

From the paleoclimate perspective, I found the IPCC's restricted discussion of the "state of the science" abbreviated at best in all of its assessment reports to date. On almost every point, I could offer a large and diverse assortment of observational studies which provide compelling alternative perspectives. Few of these were considered by the IPCC. Indeed, we see some rather odd manipulations of the peer-review and publishing processes. Regardless of one's personal predilections, the IPCC has indeed been "caught out" far too many times for its "authority" to be recognized. That does not mean its conclusions are necessarily incorrect, but it does allow significant room for doubt, which degrades its conclusions from the level of theory to hypothesis.

In terms of "runaway warming" we must also consider the lifetime of atmospheric CO2 within the framework of the carbon cycle. I don't think anyone can say with authority that predictions qualify as fact. Maybe potential future fact, but not fact sensu-restricto. They are hypotheses in this instance as there is no analog in post-MPT time from which to consider its veracity. If we are at peak oil now, and as a doubling of CO2 atmospheric concentration is taken as the certifiable result of continued fossil fuel burning emissions, and as this is postulated to result in a 3.5 W/m2 increase in thermal forcing, we find ourselves again confronted with the signal to noise ratio problem. The June 21 N65 insolation minimum during MIS-11 was about 489 W/m2. In 2004 Lisiecki and Raymo report that then, in the late Holocene, we were at 474 W/m2. Add in the 3.5 W/m2 for anthropgenic CO2 forcing and we go up to 477.5 W/m2, or about a quarter of the way to the MIS-11 insolation minimum. Or rather firmly lost in the natural climate noise yet again.

Factoring in all of this we are confronted with the term "economic benefits". As related to CO2, this term I find difficult to ponder, much less quantify in any meaningful way. As the post-MPT paleoclimate record clearly demonstrates, abrupt, dramatic, and seemingly unavoidable natural catastrophic global climate disruption appears to be the rule not the exception at the end interglacials. Isolating a single variable of anthropogenic origin might only change the outcome slightly. If CO2 is the predominant climate driver, we must therefore tackle the natural carbon cycle, something we really don't fully comprehend yet, with a zeal no one has yet offered.

Adaptation to what may be the inevitable might be a more cogent choice given that we really do not know how this works nor how to alter it with fine enough tuning to preclude catastrophic effects in either direction. From such a perspective one might be tempted to conclude that every penny not spent on fusion research might very well turn out to be a penny wasted, especially in consideration that fossil fuels represent a finite energy resource that is already succumbing to economic forces as we move towards the last half of it.

Sun, 10/24/2010 - 05:53

jason

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The Precautionary Priciple

Thanks sentient, that was an interesting and refreshing read. By mentioning the precautionary principle you took this topic into an interesting arena. But more on that later.

My background is not in climate science, and since starting this site I've always embraced comments from academics in the field; I work with paleontologists and geologists regularly, but rarely get the chance to discuss this field with them. I wrote a small article on the statistical relationship between EPICA temperature and CO2 data some time ago. I took some data from the EPICA CO2 and temperature proxy data to reconstruct this graph of recent temperature and CO2 history, in which you can clearly most of see the (probable) events in the 20 to 60 kyr BP period that you (or Sole, Turiel and Llebot) mentioned resembled our current class of temperature cycles:

Your antithesis makes the interesting proposition that a rise in CO2 concentrations might not actually be a bad thing, and you illustrated the merits of this theory quite eloquently. But I'd be interested to hear why you made these points, and whether you think that such an antithesis might actually be factual. Moreover, if it were to be the case that CO2 concentrations could blanket the end of an interglacial, how rapidly would the potential positive effects of such a possible scenario offset the risks of runaway warming in an equally (dare I say more) likely anthropogenic warming event?

This brings me back to the precautionary principle; From everything I have seen, the earth has never seen such rapid increases in CO2 (over 100ppmv in less than a century...) during the peak of an interglacial, or in any of the reconstructed EPICA histories for that matter. Given that we wouldn't see the positive effects of CO2 blanketing, avoiding or delaying the onset of a glacial period for hundreds to thousands of years, and given also the uncertainty inherent in this theory in the first place and the growing public and even scientific concensus over doomsday-like events if we do not reduce CO2 emissions, how do we best apply the precautionary principle?

To simplify (I like to simplify, sorry!), and assuming your antithesis to have qualitatively comparable merit to "IPCC theory", we arrive at a decision between economic benefit in a long period of time with immediate economic benefit now from kicking GHG reduction measures, and immediate economic costs in the form of GHG reductions, saving the immediate future from catastrophic and potentially irreversible warming while liberating humanity from an addiction to burning dinosaurs, all while placing the distant future at risk of an otherwise avoidable (antithesis) glaciation.

I would argue that the precautionary principle would lead us to avoid GHG emissions now and deal with the glaciation issue when we are equipped to do so.

I'd like to hear your thoughts.

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Sat, 10/23/2010 - 18:25

sentient

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On quoting paleoclimate data

You know, in science, there was once this thing we called the Theory of Multiple Working Hypotheses. Anathema (a formal ecclesiastical curse accompanied by excommunication) in modern climate science. So, in juxtaposition to the hypothesis of future global climate disruption from CO2, a scientist might well consider an antithesis or two in order to maintain ones objectivity.

One such antithesis, which happens to be a long running debate in paleoclimate science, concerns the end Holocene. Or just how long the present interglacial will last.

Looking at orbital mechanics and model results, Loutre and Berger (2003) in a landmark paper (meaning a widely quoted and discussed paper) for the time predicted that the current interglacial, the Holocene, might very well last another 50,000 years, particularly if CO2 were factored in. This would make the Holocene the longest lived interglacial since the onset of the Northern Hemisphere Glaciations some 2.8 million years ago. Five of the last 6 interglacials have each lasted about half of a precession cycle. The precession cycle varies from 19-23k years, and we are at the 23kyr part now, making 11,500 years half, which is also the present age of the Holocene. Which is why this discussion has relevance.

But what about that 6th interglacial, the one that wasn’t on the half-precessional “clock”. That would be MIS-11 (or the Holsteinian) which according to the most recently published estimate may have lasted on the order of 20-22kyrs, with the longest estimate ranging up to 32kyrs.

Loutre and Berger’s 2003 paper was soon followed by another landmark paper by Lisieki and Raymo (Oceanography, 2004), an exhaustive look at 57 globally distributed deep Ocean Drilling Project (and other) cores, which stated:

“Recent research has focused on MIS 11 as a possible analog for the present interglacial [e.g., Loutre and Berger, 2003; EPICA community members, 2004] because both occur during times of low eccentricity. The LR04 age model establishes that MIS 11 spans two precession cycles, with 18O values below 3.6o/oo for 20 kyr, from 398-418 ka. In comparison, stages 9 and 5 remained below 3.6o/oo for 13 and 12 kyr, respectively, and the Holocene interglacial has lasted 11 kyr so far. In the LR04 age model, the average LSR of 29 sites is the same from 398-418 ka as from 250-650 ka; consequently, stage 11 is unlikely to be artificially stretched. However, the June 21 insolation minimum at 65N during MIS 11 is only 489 W/m2, much less pronounced than the present minimum of 474 W/m2. In addition, current insolation values are not predicted to return to the high values of late MIS 11 for another 65 kyr. We propose that this effectively precludes a ‘double precession-cycle’ interglacial [e.g., Raymo, 1997] in the Holocene without human influence.”

To bring this discussion up to date, Tzedakis, in perhaps the most open peer review process currently being practised in the world today (The European Geosciences Union website Climate of the Past Discussions) published a quite thorough examination of the state of the science related to the two most recent interglacials, which like the present one, the Holocene (or MIS-1) is compared to MIS-19 and MIS-11. The other two interglacials which have occurred since the Mid Pleistocene Transition (MPT) also occurred at eccentricity minimums. Since its initial publication in 2009, and its republication after the open online peer review process again in march of this year, this paper is now also considered a landmark review of the state of paleoclimate science. In it he also considers Ruddiman’s Early Anthropogenic Hypothesis, with Rudddiman a part of the online review. Tzedakis’ concluding remarks are enlightening:

“On balance, what emerges is that projections on the natural duration of the current interglacial depend on the choice of analogue, while corroboration or refutation of the “early anthropogenic hypothesis” on the basis of comparisons with earlier interglacials remains irritatingly inconclusive.”

As we move further towards the construction of the antithetic argument, we will take a closer look at the post-MPT end interglacials and the last glacial for some clues.

An astute reader might have gleaned that even on things which have happened, the science is not that particularly well settled. Which makes consideration of the science being settled on things which have not yet happened dubious at best.

Higher resolution proxy studies from many parts of the planet suggest that the end interglacials may be quite the wild climate ride from the perspective of global climate disruption.

Boettger, et al (Quaternary International 207 [2009] 137–144) abstract it:

“In terrestrial records from Central and Eastern Europe the end of the Last Interglacial seems to be characterized by evident climatic and environmental instabilities recorded by geochemical and vegetation indicators. The transition (MIS 5e/5d) from the Last Interglacial (Eemian, Mikulino) to the Early Last Glacial (Early Weichselian, Early Valdai) is marked by at least two warming events as observed in geochemical data on the lake sediment profiles of Central (Gro¨bern, Neumark–Nord, Klinge) and of Eastern Europe (Ples). Results of palynological studies of all these sequences indicate simultaneously a strong increase of environmental oscillations during the very end of the Last Interglacial and the beginning of the Last Glaciation. This paper discusses possible correlations of these events between regions in Central and Eastern Europe. The pronounced climate and environment instability during the interglacial/glacial transition could be consistent with the assumption that it is about a natural phenomenon, characteristic for transitional stages. Taking into consideration that currently observed ‘‘human-induced’’ global warming coincides with the natural trend to cooling, the study of such transitional stages is important for understanding the underlying processes of the climate changes.”

Hearty and Neumann (Quaternary Science Reviews 20 [2001] 1881–1895) abstracting their work in the Bahamas state:

“The geology ofthe Last Interglaciation (sensu stricto, marine isotope substage (MIS) 5e) in the Bahamas records the nature of sea level and climate change. After a period of quasi-stability for most of the interglaciation, during which reefs grew to +2.5 m, sea level rose rapidly at the end ofthe period, incising notches in older limestone. After briefstillstands at +6 and perhaps +8.5 m, sea level fell with apparent speed to the MIS 5d lowstand and much cooler climatic conditions. It was during this regression from the MIS 5e highstand that the North Atlantic suffered an oceanographic ‘‘reorganization’’ about 11873 ka ago. During this same interval, massive dune-building greatly enlarged the Bahama Islands. Giant waves reshaped exposed lowlands into chevron-shaped beach ridges, ran up on older coastal ridges, and also broke off and threw megaboulders onto and over 20 m-high cliffs. The oolitic rocks recording these features yield concordant whole-rock amino acid ratios across the archipelago. Whether or not the Last Interglaciation serves as an appropriate analog for our ‘‘greenhouse’’ world, it nonetheless reveals the intricate details ofclimatic transitions between warm interglaciations and near glacial conditions.”

The picture which emerges is that the post-MPT end interglacials appear to be populated with dramatic, abrupt global climate disruptions which appear to have occurred on decadal to centennial time scales. Given that the Holocene, one of at least 3 post-MPT “extreme” interglacials, may not be immune to this repetitive phenomena, and as it is half a precession cycle old now, and perhaps unlikely to grow that much older, this could very well be the natural climate “noise” from which we must discern our anthropogenic “signal” from.

If we take a stroll between this interglacial and the last one back, the Eemian, we find in the Greenland ice cores that there were 24 Dansgaard-Oeschger oscillations, or abrupt warmings that occurred from just a few years to mere decades that average between 8-10C rises (D-O 19 scored 16C). The nominal difference between earth’s cold (glacial) and warm (interglacial) states being on the order of 20C. D-O events average 1470 years, the range being 1-4kyrs.

Sole, Turiel and Llebot writing in Physics Letters A (366 [2007] 184–189) identified three classes of D-O oscillations in the Greenland GISP2 ice cores A (brief), B (medium) and C (long), reflecting the speed at which the warming relaxes back to the cold glacial state:

“In this work ice-core CO2 time evolution in the period going from 20 to 60 kyr BP [15] has been qualitatively compared to our temperature cycles, according to the class they belong to. It can be observed in Fig. 6 that class A cycles are completely unrelated to changes in CO2 concentration. We have observed some correlation between B and C cycles and CO2 concentration, but of the opposite sign to the one expected: maxima in atmospheric CO2 concentration tend to correspond to the middle part or the end the cooling period. The role of CO2 in the oscillation phenomena seems to be more related to extend the duration of the cooling phase than to trigger warming. This could explain why cycles not coincident in time with maxima of CO2 (A cycles) rapidly decay back to the cold state. ”

“Nor CO2 concentration either the astronomical cycle change the way in which the warming phase takes place. The coincidence in this phase is strong among all the characterised cycles; also, we have been able to recognise the presence of a similar warming phase in the early stages of the transition from glacial to interglacial age. Our analysis of the warming phase seems to indicate a universal triggering mechanism, what has been related with the possible existence of stochastic resonance [1,13, 21]. It has also been argued that a possible cause for the repetitive sequence of D/O events could be found in the change in the thermohaline Atlantic circulation [2,8,22,25]. However, a cause for this regular arrangement of cycles, together with a justification on the abruptness of the warming phase, is still absent in the scientific literature.”

In their work, at least 13 of the 24 D-O oscillations (indeed other workers suggest the same for them all), CO2 was not the agent provocateur of the warmings but served to ameliorate the relaxation back to the cold glacial state, something which might have import whenever we finally do reach the end Holocene. Instead of triggering the abrupt warmings it appears to function as somewhat of a climate “security blanket”, if you will.

Therefore in constructing the antithesis, and taking into consideration the precautionary principle, we are left to ponder if reducing CO2’s concentration in the late Holocene atmosphere might actually be the wrong thing to do.

Tue, 10/26/2010 - 22:04

Anonymous

AT ALL?

You write:

To be more precise, Oxygen and Nitrogen make up 78.084% + 20.946% = 99.03% of the atmosphere. Add Argon (0.9340%) and you've got as much as 99.964% of the atmosphere composed of gases that don't contribute to the greenhouse effect at all.

don't contribute to the greenhouse effect at all.????

Really?

So i guess if our atmosphere were made up of only the GHGs (talk about thin air!) we'd have about the same temp as now.

Any sort of gaseous molecule will hold heat. You know that, don't you?

Further, your little essay has a 'scientific ring' to it, but you did not at all address what I wrote. A lot of numbers and assertions, but nothing about visualizing a cubic yard of air, and how few photons would come near any CO2 molecules.

I also read your piece attempting to deal with the CO2 lag. You say (among other things):

....and one should always be weary (did you mean 'wary'?) of arguments which use the lack of something occurring in the past, to be evidence to suggest that it cannot happen in the future.

What sort of statement is that? If something hasn't happened in the past -- like climate never having been driven by CO2 -- I'd sure take it as evidence that it won't happen in the future.

Why are you saying these things?

My interest is not in GW per se, but in why people believe what they do. Maybe you can help me out here.

Mon, 10/18/2010 - 17:22

jason

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You're not wrong, but...

Hi Allan,
I can understand where you're coming from, and I think it's important to go over what you said, because you're echoing something that many people agree with. You're not wrong in saying that CO2 makes up a small fraction of the atmosphere, but that doesn't mean that it doesn't have a huge effect on the greenhouse effect.

CO2 makes up around 0.039% of the atmosphere in volume, somewhere around 1/2,500 of the total atmosphere. However, we must remember that the majority of the atmosphere is composed of Nitrogen (78%) and Oxygen (21%). To be more precise, Oxygen and Nitrogen make up 78.084% + 20.946% = 99.03% of the atmosphere. Add Argon (0.9340%) and you've got as much as 99.964% of the atmosphere composed of gases that don't contribute to the greenhouse effect at all.

This means, that in the dry atmosphere (not considering water vapor), CO2 makes up somewhere between 90%-100% of the total volume of greenhouse gases in the atmosphere. Its Global Warming Potential is not so high, but other gases with higher GWPs are also being emitted by humans at alarming rates. Let's not forget that the human effect on the greenhouse effect through H2O concentrations is negligible, so in terms of anthropological effects, we don't need to consider anthropological H2O emissions.

CO2 concentrations reached 389ppmv this year (see co2now.org), and given that preindustrial CO2 concentrations were 280ppmv, we have seen a rise in CO2 concentrations of almost 40%. Assuming that CO2 is responsible for only 15% of the total greenhouse effect (this value could be higher if you consider methane, NOx, and other gases produced through human activity), this still leaves a very significant 5% or so change in the greenhouse effect from anthropological activity.

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Mon, 10/18/2010 - 14:14

Anonymous

A miniscule mirror

By volume, CO2 represents about 1/4,000 of our atmosphere. (400 ppm in air, estimating on the high side.)

So picture a cubic yard of air. Picture a mirror approximately one inch in diameter (do the math) suspended in that cubic meter of air. (You'd almost have to squint to see it.) It's pointed down, to reflect back to earth infrared radiation (imagine the mirror could do this). This is what CO2 does, right? Reflect back infrared energy.

No, now wait. We're talking about anthropocentric CO2 (1/20th of the total CO2 in air), so the 1/20th of an inch mirror is actually too small to see without a magnifying glass.

Now picture how much heat would be reflected back to earth by our miniscule mirror as infrared energy passes through the cubic meter of air.

Correct me if my visualization (or my math) is wrong, but COMMOM SENSE tells me that CO2 as a driver of Global Warming or whatever it's called right now is.... incorrect is the kind word.... hoax is the other word that comes to mind

Wed, 10/27/2010 - 04:45

jason

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Posts: 105

Re: Reply

Sorry about taking so long to get back to you; I've been busy making changes on the site. You can now add pictures to your comments, however I suspect that I might end up with some spam problems so in the future you might have to register to add pictures (you can do that here: http://www.warmdebate.com/user/register). Please do add the pictures, I'm interested to see them.

Quote:

In terms of "runaway warming" we must also consider the lifetime of atmospheric CO2 within the framework of the carbon cycle.

Here is a photo of the life of a CO2 pulse I made according to the Bern CC Climate model as used by the IPCC AR4:

This also happens to be a plot of man's political horizon of interest, and in my eyes the most compelling argument for why we should be (or at least are) worried about CO2. I studied engineering and a very political masters degree in sustainability, so I admit there is a big black hole in my knowledge of the very field you specialize in, so forgive me for going back to basics, but wouldn't you agree that our decidedly poor understanding of climate systems weighed against our very good understanding of CO2 chemistry should lead us to infer as much as possible from the latter? I dare also to ask the question: How applicable is paleoclimatic science to a problem which not only sees a hitherto unheard of rate/mechanism of CO2 emission, but also gives CO2 as an independent variable rather than a feedback element in the system. Have we thus broken some of the "omnipresent" mechanisms in our climate history?

Quote:

If a single variable such as CO2 is taken to be the dominant causative variable of the MIS-11 and MIS-5 highstands, and anthropogenic emissions of CO2 the causative agent of a Holocene highstand which has not yet happened, then the CO2 problem is probably worse than we thought. Imagine applying any single or combination of CO2 reducing strategies, including geoengineering to quash the anthropogenic IPCC AR4 worst case signal. Given that is has happened several times before (there were at least 3 highstands in MIS-5 greater than present, and at least 2 in MIS-11), we might very well watch sea level (and presumably global temperatures) soar 10 to 33 times the IPCC AR4 prognosticated level anyway. To quash this amount of CO2 forcing we would have to mount an effort against natural causation orders of magnitude greater than what has so far been proposed.

I think it's fair to say this is not a target we should hope to achieve. But I come back to my last post; don't the timescales of anthropological CO2 emissions and glaciation periods (and the mentioned oscillations in temperature therein) occur on completely different orders of magnitude? I'd be really interested to see an FFT plot of ice core temperature proxies to answer this question, although I don't know if the "noise" would be a little high to get any useful data out of such an analysis. I'll dig through my EPICA data a little later and try to create such a plot; maybe you can comment its relevance.

Supposing that the mechanisms that cause the degree of complexity of interaction we see in the historic reconstructions can really only occur on the timescales of those reconstructions (thousands of years), maybe the assumption that CO2 increase on decadal timescales is akin to the CO2-in-a-box climate forcing models is not so wrong? While natural variation in insolation does exceed the theoretical radiative forcing of industrial CO2 increases, it does so on a higher frequency, generally oscillating about what we might consider a mean for the foreseeable past and future (in terms of our political interest plot). Here is a plot of milankovich cycle-related insolation forcers:

The picture I'm building here, is that the natural cycles occur on a combination of very high or very low frequencies, such that the changes are either insignifcant to the anthropological rates of emissions, or so high and oscillating about a mean that they don't have a net effect over the timescales of our anthropological CO2 emissions. Is this a valid ascertion?

For me, an important question is: Does the past tell us anything about today? More importantly, can the past show us that the radiative forcing of CO2 is not the major mechanism at work for the relevant timescales? This really become a question of on whom (or which theory) the onus of proof should be placed, doesn't it?

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Thu, 10/28/2010 - 02:10

sentient

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Re: The facts about Global Warming (discussion)

Well, I registered to possibly relieve any spam issue, however from your most recent post, we have encountered the next technical hurdle. The answers to many of your questions and data needs are more easily provided by provision of the research papers themselves. This would be of immense help to me as I was diagnosed on Sunday in the ER, and am now suffering through, my first ever case of pneumonia. A feverish brain is not the best thing to tackle such complex subjects with. And I really should be in bed not on this keyboard. That, of course, is in addition to the far more preferable pleasure of reading the papers themselves.

Alternatively, perhaps you could figure a backchannel way for me to transmit them to you. In the meantime, I will provide literature references or links where appropriate.

In reading your post it may be best to work through it a bit out of order, or in the first instance in parallel. The premise that CO2 is the major climate forcing agent is presently addressed in what may become a landmark paper. It is currently in press and you can download it here:

http://www.fel.duke.edu/%7Escafetta/pdf/scafetta-JSTP2.pdf

A few years ago a colleague asked me if there was a definitive source of the various intimations regarding cosmic climate forcings. At that time I was unaware of a single source, but of a plethora of papers addressing things as seemingly insignificant as the length of day to the galactic cosmic ray hypothesis of Svensmark. In this paper, Nicola Scaffeta takes us on a ride through almost everything in between, with hat tips to those endpoints. To make the long story short, he examines the gravitational effects predominant within the solar system from the Jovian system, Jupiter, Saturn, Neptune and Uranus, providing us with a detailed look at the sub-millenial (eccentricity, obliquity and precession) which appear to also pace climate cycles on earth. The IPCC models get a pretty poor report card here as they (also) do not incorporate any aspect of these factors.

In fact the past does tell us a lot about today. In particular, the high resolution GISP2 records provide telling results on the short term that CO2 does not drive the D-O abrupt warmings which happen on the millenial scale (m=1,470 yrs, range-1-4k yrs). As Sole, Turiel and Llebot confess, they were not expecting this result. Both the Greenland and Antarctic cores provide strong evidence that CO2 follows the major glacial interglacial transitions, but does not drive them.

Now this next bit will have to be from memory for either I did not save it, or I saved it somewhere that I cannot find it now (the climate change and evolution main folder in my cybrary contains 198 subfolders and 5,542 papers). A recently begun new core at what is considered to be an optimum location (I believe) on a ridge saddle location in the western part of Antarctica hopes to definitively answer the question of which came first, temperature of GHGs. If I remember correctly, we should begin to see published results within the next year or so. The press release I read was not specific as to what new core analysis technique(s) were to be applied, and I simply can't figure out where I put the pdf!

In terms of your assertion's validity, the answer is not only complicated but populated with unknowns. We simply do not know yet what causes the D-O abrupt warmings, and whatever causes them seems to be the cause of "a similar warming phase in the early stages of the transition from glacial to interglacial age" to quote Sole et al yet again (simply because it was readily accessible as a quote above, if I wasn't burning up with fever I would dig up many more such quotes).

In my case I am not trying to build any picture, just trying to discern the one in front and behind me with an eye on what that might mean ahead. Try to think of the difference as being akin to the difference between an analyst and an advocate. The analyst searches for the truth, and presents all sides of the case with equal emphasis. The advocate, by contrast, presents a biased version of the truth and tries to prove he/she is right, and his/her opponent is wrong. What we do seem to know is that CO2 does not credibly seem to have been the agent provocateur of climate change in the past. What we do not know is if CO2 can be one in the future as related to anthropogenic contribution to CO2 rise.

I was disappointed in your answer to my quote you provided.

Quote:
I think it's fair to say this is not a target we should hope to achieve.

For me it is a real mindbender to shove ahead with climate mitigation schemes to suppress a consensus anthropogenic signal which might very well be no more than 10% of a natural noise event which would make our commitment of global treasure to do it completely moot. Paint the picture. The year is 2100, our progeny are all standing around patting each other on the back, congratulating ourselves on quelling that 0.58 meter IPCC AR4 rise, presumably drinking non-carbonated champagne, while sea level rises to +6 meters anyway. Only fools are proud of a fool's errand successfully completed. Against even there own knowledge, the ACOE built the dikes around New Orleans only to watch Katrina rend them asunder. To this very day they disavow their own findings of their own work beforehand.

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"How applicable is paleoclimatic science to a problem which not only sees a hitherto unheard of rate/mechanism of CO2 emission, but also gives CO2 as an independent variable rather than a feedback element in the system."

Entirely dependent upon your assumption on the efficacy of CO2 as a climate forcing. The paleoclimatic data inform me that the abrupt warmings happen regardless of CO2 concentration. Even with CO2, the warmings eventually decay back to the dominant climate state at the time anyway. An effect, not a cause. I take your graph (unqualified) as a measure of some hope at the end Holocene, for if it does have the climate effects we see in the paleoclimate record, the more we "security blanket" we can stuff into the atmosphere, the less likely we we will be subject to whatever are the major climate forchings. And especially so at the probable end Holocene. From all the research I have done, I soon moved from CO2 as an independent variable to a dependent variable, primarily dependent upon temperature and time. I am afraid "that dog doesn't hunt" with me. The observational data are just too solid.

And our good understanding of CO2 chemistry? As a single variable which at present concentrations is nearly fully spectrally saturated? I think that what we know about a single variable in a system populated with demonstrably larger known variables, and even larger unknown variables (what causes glacial terminations, D-O abrupt warmings?) represents but a single piece of an astonishingly large puzzle that we are still quite some time away from really understanding. Meaning conclusions are beyond that.

So here is the first figure from my previous post (can't find the MIS-11 one):

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Rohling et al, Nature Geoscience, vol 1, Jan 2008

Fri, 10/29/2010 - 10:50

jason

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Re: The facts about Global Warming (discussion)

Thanks for the link (the Nicola Scafetta article), that really addresses my previous post, although I must admit it does add to my confusion about global warming. I had always explained the lack of correlation between IPCC and reality prior to the 1970s by the dominance of solar cycles, with a growing role of CO2 overtaking the effect from solar variation in the 70s. Here is a simple solar irradiance/surface temperature plot of the 20th century illustrating this quite eloquently:

Solar irradiance, plotted against global temperature

I was especially fascinated by the ascertion that 60 year cycles can explain so much from the above graph:

Quote:

The temperature record presents a clear 60-year cycle that oscillates around an upward trend. In fact, we see the following 30-year trends: 1850–1880, warming; 1880–1910,cooling; 1910–1940, warming; 1940–1970, cooling; 1970–2000, warming; and, therefore, a probable cooling from 2000 to 2030

Source: Scafetta,N. , Empirical evidence for a celestial origin of the climate oscillations and its implications. Journal of Atmospheric and Solar-Terrestrial Physics(2010),doi:10.1016/j.jastp.2010.04.015

The years 2000-2030 will no doubt be a decisive period. I don't know if the ideas presented here (Figure 1) are new, but from what I'm seeing (and I'm doing my best to follow), graphs like Figure 10A really punch home a powerful new message. I've reproduced the graph here:

Rescaled SCMSS 60 year cycle (black curve) against detrended surface temperature Source: Scafetta, N. (2010)

To see if I'm understanding correctly, at this point the article makes the statement that oscillating elements in the temperature trends from planetary motion a) exist in the form of predominantly 20, 30 and 60 year cycles represented by the black line and b) when an increasing trend is removed from the temperature history the only major remaining elements are accurately predicted by the aforementioned cycle. Conversely, adding a trend to the cycle and plotting it against actual temperature history also (and logically) yields the same very beautiful correlation:

Trended SCMSS 20, 30 and 60 year cycles against surface temperature (Scafetta, N

The question on my mind now is; do you know of any work where the IPCC correlation of temperature and GHG emissions has been used to scale the SCMSS 20/30/60 year cycles and compare that result to the actual temperature history (rather than using that history to trend the cycles)?

Quote:

I was disappointed in your answer to my quote you provided.

I think you may have misunderstood what I meant. I think it's not realistic for us to hope to force the atmosphere to correct for the massive changes in temperature associated with the earth's natural cycles. The question for me is a) how strong is our contribution and how certain are we of the answer and b) how much time do we have before our hypothetical efforts are quashed by the earth's natural (and much stronger) cycles. If we are really only contributing an amount smaller than background noise, and we are doomed to floods of unseen proportions in 100 years anyway, then maybe we should refocus our efforts.

If, on the other hand, we are not sure whether those corrected upward trends seen in Scafetta (2010) are caused by anthropological emissions of GHGs, and if we only think there might be a natural change in global temperature sometime in the next 1,000 years, then maybe this paints a different picture? You're in a far better position to answer how far this picture be from the truth.

Quote:

And our good understanding of CO2 chemistry? As a single variable which at present concentrations is nearly fully spectrally saturated?

I suspect you know something I don't, but based on a simple empirical saturation relationship from Myhre et. al 1998 and an IPCC prediction mean for CO2 concentrations in 2050 I created this plot:

Source: Radiative forcing and CO2 emissions

By making the statement about our understanding of CO2 chemistry, I simply meant that I would be inclined to infer as much as possible for what we do know. Given that CO2 in a box gets hotter more quickly than Nitrogen in the same box, wouldn't it be prudent to assume that CO2 will cause the atmosphere to increase in temperature until an argument to suggest otherwise comes along? I understand that CO2 was not a significant driver or even feedback element in past temperature changes, but given the scale of CO2 increases, the increase in CO2 without the prior increase in temperature, and - perhaps most importantly - the stakes, it makes sense to permit politics to follow the IPCC?

I'm not saying science should be content with this, but maybe policy makers should be. Having said that, I think I've learned a lot from your posts and submitted articles, and even more since writing the "Facts about Global Warming" article, which I would now describe as blatantly naive. I suppose in that sense I've achieved a lot of what I intended to in creating this website; to learn about something which confused the hell out of me.

I took my undergrad in Australia, and while I love the country and am quite happy with its political course, I have come to distrust it's infatuation with coal. After graduating I moved to Germany to begin my Masters degree, and began to see economic role of renewables quite differently. Before moving to Germany I saw the answer to how we should act in response to global warming quite simply as a question of "Cost of using renewables" against "cost of global warming risk potential". All the while in Bavaria, Germany, the economy is booming from investments from renewable technologies, households are making a killing from solar, farmers are getting rich by producing biofuels and selling the fertilizer biproduct, and despite all this Bavaria still has a food surplus. Germany's actions have led to growing independence from Russia's gas lines and put it at the forefront of Biofuels research. If a country that was literally flattened less than 70 years ago can rise to become Europe's largest economy and a global leader in renewables without access to any material amount of natural resources, then maybe we could do worse than to take 21st century Germany as an example for how we should run other modern economies...

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Solar irradiance, plotted against global temperature

Rescaled SCMSS 60 year cycle (black curve) against detrended surface temperature (gray) (Scafetta, N. 2010)

Trended SCMSS 20, 30 and 60 year cycles against surface temperature (Scafetta, N. 2010)

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Fri, 10/29/2010 - 11:16

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jason

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Posts: 105

Re: AT ALL?

Quote:

Any sort of gaseous molecule will hold heat. You know that, don't you?

I think you may have misunderstood the concept of the greenhouse effect. The greenhouse effect refers to the atmosphere's tendency to trap incident radiation from the sun. Nitrogen and Oxygen don't contribute to this effect, despite, as you mentioned, possessing the capacity to hold heat (all materials do this, but not all absorb incident solar radiation in significant amounts).

Quote:

So i guess if our atmosphere were made up of only the GHGs (talk about thin air!) we'd have about the same temp as now.

Well, no, I couldn't possibly know what the earth would be like if we just removed all the nitrogen and oxygen. What I would say with some certainty is that the world would get hotter if we replaced the aforementioned gases with CO2. There is plenty of evidence for similar effects both in earth's distant past and planets such as Venus. But I don't think that's relevant, concentrations of CO2 won't increase enough to offset any measurable amount of the atmosphere so it's not really a useful example.

Quote:

Further, your little essay has a 'scientific ring' to it, but you did not at all address what I wrote. A lot of numbers and assertions, but nothing about visualizing a cubic yard of air, and how few photons would come near any CO2 molecules.

The answer to your question (as I understand it) is quite simply the relationship between CO2 in the atmosphere and its theoretical influence on that volume of air. The answer to this is quite simple, but unfortunately not entirely relevant, because it does little to tackle the big questions (such as; is such a simple model realistic?). Below is a plot of the increase in radiative forcing from CO2 in the atmosphere based on empirical forcing relations:

Radiative Forcing of CO2 in the Atmosphere

Quote:

....and one should always be weary (did you mean 'wary'?) of arguments which use the lack of something occurring in the past, to be evidence to suggest that it cannot happen in the future.

Yes I meant wary :) thanks for pointing it out I've changed it now. I get a bit trigger-happy with spellcheck sometimes. I was simply making a logical ascertion; the fact that something has not happened in the past is not evidence of its inability to happen in the future. It might suggest that it won't happen in the future, but it doesn't suggest that it can't. That's all I was saying. The reason this distinction is important is because the conditions have changed somewhat from those past examples, and we need to be aware of the possibility that the past does not limit what CO2 can do in the future in this particular case. There is no proof that CO2 can or cannot drive large changes in global temperature. There is however evidence pointing in both directions.

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Radiative Forcing of CO2 in the Atmosphere

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