NASA and Global Warming junkscience

[Ken G]

In your apparent rush (54 minutes max.) to misrepresent what I was saying (many factual errors), I see you completely missed the relevence of the linked scientific paper from the Naval Research Laboratory (NRL), which aside from the main focus of global weather modelling specifically mentions the implications of truncation errors caused by choice of time step and 3D grid sizes for climate models, and goes on to suggest a possible way to reduce it through using logarithmic time steps that are a bit smaller with each subsequent step.

No, sounds like I represented you accurately. From the beginning, I have objected to your clearly stated and oft repeated claim that any time you have feedback, you have an insurmountable truncation error problem. Instead, I have pointed out that responsible scientists who do such calculations know all about numerical errors (hence the point made in the article of how to improve the situation). But your claim was that the results are complete garbage because all you are seeing is the result of truncation errors, which go unstable and it's just like why we can't predict weather (which is an issue of Lyapunov exponents, by the way). So let me get this straight... now you are telling me that the authors are admitting their simulation is junk because they are just publishing a bunch of snowballing truncation errors?


I went into some depth on Global Circulation Models in weather forecasting mode as that is what I do know something about, discussing some behavioural characteristics of the models in weather mode, and made the point that with a few modifications these are the same models used for climate modelling in many cases.
Yes, I caught that part. And I told you that "weather mode" has different objectives, and so different error issues. It makes no difference that the simulations are essentially the same. I repeat my dynamite analogy.


As both model modes use non-linear functions like the Lorenz equations for convection heat transport in the atmosphere, so systematic errors due to choice of equal time step intervals and 3D grid dimensions apply in both cases.
The thermodynamic principle of ergodicity is relevant here. In thermodynamics, it is impossible to predict exactly where the particles will go, or where the milk goes when you stir your coffee. But it isn't garbage, because statistically, we know all possibilities on a simply connected energy surface will eventually be visited. So if you want to predict weather, you can't do it, but if you want to understand global climate trends, you only need a complete treatment of the energy surface. That involves different error issues, and I'll bet you that the authors don't think their simulation is junk, so why quote them to support your position?


I also mentioned the lack of data in a global sense being a problem due to interpolation uncertainties, and made the point that climate data is quite different to weather data although it is derived from it using long-term numerical averaging, and that even though the models are functionally quite similar, models in climate mode will behave significantly better because of the reduced level of chaos.
Ah, well there's the rub. "Significantly better" vs. "complete garbage". Now you are claiming global models are currently both at the same time, leaving me confused.



I have no doubt that within a few years the models will be significantly improved for both climate prediction and weather forecasting when enough people get their heads out of the sand to see that there seems to be a real issue here concerning truncation errors in complex non-linear 3D grid models with large numbers of equal time steps that needs to be addressed, and do something about it.Well, we can agree that model improvements are needed. The real issue is, when the improvements are included, do you really think the current results will be rendered completely meaningless as you claim? Time will tell on that one.

[Carl_Smith]

...But your claim was that the results are complete garbage...
...Ah, well there's the rub. "Significantly better" vs. "complete garbage". Now you are claiming global models are currently both at the same time, leaving me confused....
...do you really think the current results will be rendered completely meaningless as you claim?Misrepresenting me again.

I have searched the last 4 pages of this thread, and the only person to use the terms "complete garbage" and "completely meaningless" was you. The term I frequently used was "unreliable", which is a far cry from either of your versions.

Climate modelling is "significantly better" than weather forecasting for the reasons I mentioned, but IMO it is still "unreliable" for reasons I mentioned, and the paper I referenced points in that direction.

I am sure many readers can make up their own minds about what I have written without you putting words in my mouth that I did not say, and I think many would rather read about the real issues around global warming than your misrepresentations of what I said.

I think I'm through bothering to respond to your posts, as it just uses valuable forum bandwidth and is a waste of everyones time.

[grant hutchison]

I think I'm through bothering to respond to your posts, as it just uses valuable forum bandwidth and is a waste of everyones time.Please don't stop on my account. Your responses to Ken, and Ken's to you, are doing much to illuminate my thinking on global warming.

Grant Hutchison

[pghnative]

While I think it's good to keep an open mind about these kind of things, I would take much of what that greenhouse skeptics say with a large grain of salt - it seems that many of the high profile enhanced greenhouse effect skeptics are paid by the oil industry.
Isn't that essentially an ad hominem attack?

Though I agree that published conclusions should be looked at skeptically. Conclusions from both sides.

[Ken G]

Misrepresenting me again.

I have searched the last 4 pages of this thread, and the only person to use the terms "complete garbage" and "completely meaningless" was you. The term I frequently used was "unreliable", which is a far cry from either of your versions.
Much as I hate to get into "he said she said" debates, the shifting sands of your position causes me to do a little quoting. How about:



To use these same (or similar) GCMs with a few tweaks for inclusion of 'greenhouse gas' assumptions to run climate simulations decades or more into the future has both great entertainment value and real curiousity value, but is really bad science when billions of dollars of public money is being spent largely on the basis of the output of such models.

OK, now maybe what you were trying to say was these simulations are "unreliable", but to my ears, citing 'exponential growth' of errors and characterizing simulations as being of "entertainment value" that is ultimately "bad science" sounds a little like you were saying their results were garbage. My mistake. Also, I can't really say that any particular simulation isn't complete garbage, you are right that climatologists don't always have the required numerical expertise (for example, you mentioned that they suggested using logarithmically smaller timesteps to reduce error, and that is the most catastrophically silly idea I've ever heard for open-ended time simulations. It would only make sense for simulations approaching some kind of catastrophe in a finite time and they wanted better resolution for how the catastrophe occurs.) Still, you certainly have brought some interesting data into the discussion with well presented graphs, so I must thank you for giving me the clearest observational indication I've ever seen that high CO2 levels do indeed cause global warming.

[Peter Wilson]

On the one hand, you have quantum entanglement: a photon that decides it is right-circularly polarized can effect an entagled photon a billion light-years away, causing it to beome left-circularly polarized, through the most ephemeral, mysterious interaction. On the other hand, you have the global warming skeptics insisting that 6 billion humans--including 100 million Americans driving SUVs--cannot possibly effect the weather!

Those pesky humans think they can do a lot...but luckily, one thing they can't possibly do is effect the weather :rolleyes:

Alright all you smarty-pantz GW skeptics, answer this one: If we can put a man on the moon, how come we can't effect the weather?

[publius]

Alright all you smarty-pantz GW skeptics, answer this one: If we can put a man on the moon, how come we can't effect the weather?

If we can put a man on the moon, how come we can't put a man on the sun?

If we can put a man on the moon, how come we can't go faster than light?

If we can put a man on the moon, how come we can't cure cancer?

If we can put a man on the moon, how come we can't eradicate fire ants? That's one near and dear to me.

If we can put a man on the moon, how come 2+2 can't equal 5 if we want it to be?

If we can put a man on the moon, how come I can't have a harem of supermodels?

If we can put a man on the moon, how come we can't do anything we want?

-Richard

[Kaptain K]

If we can put a man on the moon, how come we can't put a man on the sun?
Because
If we can put a man on the moon, how come we can't put a man on the sun?
Because
If we can put a man on the moon, how come we can't go faster than light?
Because
If we can put a man on the moon, how come we can't cure cancer?
Because
If we can put a man on the moon, how come we can't eradicate fire ants? That's one near and dear to me.
Because
If we can put a man on the moon, how come 2+2 can't equal 5 if we want it to be?
Because
If we can put a man on the moon, how come I can't have a harem of supermodels?
Because
If we can put a man on the moon, how come we can't do anything we want?
Because
If we can put a man on the moon, how come we can't go faster than light?
Because
If we can put a man on the moon, how come we can't cure cancer?
Because
If we can put a man on the moon, how come we can't eradicate fire ants? That's one near and dear to me.
Because
If we can put a man on the moon, how come 2+2 can't equal 5 if we want it to be?
Because
If we can put a man on the moon, how come I can't have a harem of supermodels?
Because
If we can put a man on the moon, how come we can't do anything we want?
Because

[GOURDHEAD]

Yes, the combination of changes in earth's orbit and tilt are called Milankovitch cycles and are well understood and are related to the spread and retreat of glaciers. What is intersting is that they should cause relatively small changes in the earth's climate but it appears there are a variety of positive feedback mechanisms which can increase their effect and result in glaciation or the retreat of glaciers. The earth's climate seem relatively delicate in this regard, where a small initial change can have large scale effects.
Can someone tutor me, either with links or a paragraph or two, on the cause(s) of the variation of the eccentricity of the Earth's orbit seemingly manufactured in Milankovich's "epicycle" shop in an attempt to explain (interpret) depositions found in ice and ocean bottom test cores. These changes in the eccentricity of the Earth's orbit have been described as having a 100,000 year and a 400,000 year component, although I have not found an assertion about their phase synchronicity. The 100,000 year component seems to have the same period as the one asserted to exist for the alignment of the orbital planes of Jupiter and the Earth. Since we can't have directly observed any of these cycles from start to finish, what is the analytical basis for assertion of their existence?

[Monique]

Isn't that essentially an ad hominem attack?


While I think it's good to keep an open mind about these kind of things, I would take much of what that greenhouse skeptics say with a large grain of salt - it seems that many of the high profile enhanced greenhouse effect skeptics are paid by the oil industry.

Though I agree that published conclusions should be looked at skeptically. Conclusions from both sides.
Apparently he does not read wikipedia entry or perhaps he think Zachos et al. (2001) in pay of oil interest.

I have questions concern global warming also, oil industry owe me checki!! :p

[grant hutchison]

Can someone tutor me, either with links or a paragraph or two, on the cause(s) of the variation of the eccentricity of the Earth's orbit seemingly manufactured in Milankovich's "epicycle" shop in an attempt to explain (interpret) depositions found in ice and ocean bottom test cores.Sorry, I can't provide the specifics.
I'm just intruding to say that your phrasing seems to suggest the wrong ordering of events. Milankovic spent thirty years around the start of last century doing paper calculations of the insolation at a few (northern) latitudes, looking for periodicities that might explain the rather gross details of glacier advance and retreat, and identified the 100, 41 and 23 kyr orbital periodicities that bear his name.
The ice and seabed cores came decades later, when Imbrie, Shackleton and Hays performed a spectral analysis on the climatic "signal" from various cores, and found Milankovic's periodicities falling out at them.

Grant Hutchison

[Ken G]

I don't know who could give you those specifics as to what causes the cycles, you'd probably be better off googling it. It is just gravity, of course, but it is way down in the details of what gravity from non-central masses do to non-spherical objects, so it's way beyond what most of us can reproduce by just thinking about it.

[Tim Thompson]

If the solar system consisted of the sun & Earth only, then there would be no Milankovitch cycles. But there is the moon to consider, which affects the tilt of Earth's axis ("obliquity"), and the other planets (mostly Jupiter). And since the planets don't all really sit in the same plane, all of the perturbative forces have both horizontal & vertical components. The result is that Earth's orbital eccentricity, inclination & obliquity are all pumped by the periodic motions of the other planets, and the moon. I don't know of a good source to describe the details of how they are caused, off hand, but I should, since it's an interesting problem. I'll see what I can find. Meanwhile, check out Breakthrough Made in Dating of the Geological Record (http://www.agu.org/sci_soc/eos96336.html), from the AGU newspaper EOS. It's old, dating from 1997, but still shows that the Milankovitch Cycles (sometimes called Astronomical Cycles) can be calibrated by radiometric dating methods. Milankovitch Cycles and Glaciation (http://www.homepage.montana.edu/~geol445/hyperglac/time1/milankov.htm) describes the cycles, but does not say much about what causes them.

[Tim Thompson]

Here is a non-mathematical webpage that explains the basic celestial mechanics, much as I did, but they do have a list of references to technical papers that will give you the real deal, if you want it: Climate, Astronomical Forcing, and Chaos (http://www.ldeo.columbia.edu/~polsen/nbcp/cmintro.html), from the Lamont-Doherty Earth Observatory (http://www.ldeo.columbia.edu/) at Columbia University (http://www.columbia.edu/). Perhaps the most interesting of the reference papers is this one:


Stability of the astronomical frequencies over the earth's history for paleoclimate studies (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1992Sci...255..560B&db_key=AST&d ata_type=HTML&format=&high=44739db64323919); Berger, Loutre & Laskar, Science 255: 560-566, 31 Jan 1992.
Abstract: The expected changes over the past 500 million years in the principal astronomical frequencies influencing the earth's climate may be strong enough to be detectable in the geological records, and such effects have been inferred in several cases. Calculations suggest that the shortening of the earth-moon distance and of the length of the day back in time induced a shortening of the fundamental periods for the obliquity and climatic precession, from 54 to 35, 41 to 29, 23 to 19, and 19 to 16 thousand years over the last half-billion years. At the same time, the precessional constant increased from 50 to 61 arc seconds per year. The changes in the frequencies of the planetary system due to its chaotic motion are much smaller; their influence on the changes of the periods of climatic precession, obliquity, and eccentricity of the earth's orbit around the sun can be neglected. Eccentricity periods used for Quaternary climate studies may therefore be considered to have been more or less constant for pre-Quaternary times.

Unfortunately, the paper is not readily available online (requires subscription). Unlike some journals, Science, the AGU journals & Nature, never release their papers without a subscription. But Science is not that hard to find in almost any library.

Laskar is the one who has done most of the work on exploring the applications of chaos theory in orbital mechanics, and is the one you want to write a paper like this (most likely Berger & Loutre were grad students supervised by Laskar, which is why Laskar is last in line). There is quite a bit of published evidence for observing Milankovitch Cycles in the geological record, although the mechanism by which climate is affected, presumably changes in insolation, remains unclear. See, i.e., Berger, Melice & Loutre, 2005 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005PalOc..20A4019B&db_key=PHY&d ata_type=HTML&format=&high=44739db64300371), Liu, Altabet & Herbert, 2005 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005GeoRL..3223607L&db_key=AST&d ata_type=HTML&format=&high=44739db64300371), Anastasio, et al., 2005 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005AGUFMPP51C0618A&db_key=PHY&d ata_type=HTML&format=&high=44739db64300371), Calov & Ganopolski, 2005 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005GeoRL..3221717C&db_key=AST&d ata_type=HTML&format=&high=44739db64300371), Khodri, et al., 2005 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005E%26PSL.236..285K&db_key=AST &data_type=HTML&format=&high=44739db64300371), Shevenell & Kennett, 2004 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004AGUFMPP11A0542S&db_key=PHY&d ata_type=HTML&format=&high=44739db64300371). They aren't available online, you have to dig them up the old fashioned way, but such is life.

The list can be quite lengthy. My only real points here are that (1) the Milankovitch cycles, theoretically, are the product of legitimate celestial mechanics, and (2) the Milankovitch cycles are evident in the paleontological record. The observed cycles do correlate with evidence of climate change, but climate dynamics is of course a hot topic, and one still under detailed study.

As a final note, I will express my opinion that global warming as "junk science", as implied by the title of the thread, is simply preposterous. This has no bearing on whether or not anyone's particular explanation is right or wrong, but is meant to emphasize that this is an inquiry based on & involving valid, proper science. "Junk science" is a term used by politicians, who usually prefer to avoid thinking whenever possible.

[Ken G]

I agree. The only extent to which it could be "junk" is if it is (1) an example of people simply jumping on a bandwagon to get their stuff published, or (2) an example of people supporting a pre-arranged conclusion in order to obtain funding from self-interested parties. Either or both of those effects may be in place to some extent, on opposite sides of the debate, but to say that this accounts for the majority of what the scientific community is doing on this question is no better than a conspiracy theory and should be in that portion of the forum.

[GOURDHEAD]

I'm just intruding to say that your phrasing seems to suggest the wrong ordering of events. Milankovic spent thirty years around the start of last century doing paper calculations of the insolation at a few (northern) latitudes, looking for periodicities that might explain the rather gross details of glacier advance and retreat, and identified the 100, 41 and 23 kyr orbital periodicities that bear his name.
The ice and seabed cores came decades later, when Imbrie, Shackleton and Hays performed a spectral analysis on the climatic "signal" from various cores, and found Milankovic's periodicities falling out at them. Thanks Grant for correcting the order of events. Since Milankovich seems to have introduced the idea of such a large variation in the eccentricity of the Earth's orbit, what did he base it on?

Also, thanks to each of you for the links.

[grant hutchison]

Since Milankovich seems to have introduced the idea of such a large variation in the eccentricity of the Earth's orbit, what did he base it on?On the sort of perturbation calculations that Tim and Ken describe, and his results have been borne out by more modern analyses.

Grant Hutchison

[GOURDHEAD]

Sediment deposition analysis, though a solid observation artifact, seems to be a weak reason for positing a variation in Earth orbital eccentricity. Especially so in the absence of a firm gravitational reason for the significant changes assumed. The other "orbital" variations each have confirming observational measurements to back them up; unlike the eccentricity variations which are of such long duration that we haven't been around long enough with sufficient technology to collect confirming data. I hunger for at least a plausible hypothesis for what seems to me to be an exceptional conclusion. I don't mean to be attacking Milankovich; I'm just trying to understand this aspect of the claim prior to swallowing it hook line and sinker.

Is the orbital eccentricity variation intended to imply changes in area of the ellipse (kinetic energy variation) or just a variation in its shape without significant energy variations? This looks like bait for the Nemesis promulgators.

Can it be totally due to the chaotic characteristics of the multi-body configuration of the solar system that could lead to an aphelion for Earth coinciding with a perihelion of Mars, the orbit of each having been chaotically disturbed, that could drastically alter the orbits of each beyond recovery---sans Nemesis.

[Ronald Brak]

A quick overview of Milankovich cycles which I hope is correct:

The earth spins on its axis and this axis is tilted, giving us seasons. But while the earth spins the axis also moves in a circle once every 26,000 years. When combined with the eccentricity of earth's orbit this means that sometimes winter will be more servere when winter in one hemisphere coincides with the earth being from the sun and other times winter will be milder when it coincides with the earth being closer to the sun.

The earth's axis varies from a tilt of 22.1 to 24.5 degrees over 41,000 years. The reason it does this is quite complicated and I can't really explan it here. (Translation: I don't know why.)

On top of this earth's orbit can vary from an eccentricity of almost zero to to almost 0.05 due to the gravitational influence of other planets (mainly Jupiter).

The effects of these cycles on the amount of solar radiation received by the earth's hemispheres can be calculated. Sometimes they act to cancel each other out, other time they work together to make earth's climate warmer or cooler than the mean.

These cycles appear to be responsible for the warming first experienced when the earth comes of a glacial period. Increased warming appears to occur due to greenhouse gases. This explains the lag between temperature increase and CO2 concentrations. Presumably it takes hundreds of years for the oceans to warm and release CO2. CO2 and methane released from thawing tundra presumably also have an effect. Methyl hydrates releaseing methane could be another factor. The melting of ice reducing the earth's albedo is also another effect.

[jlhredshift]

These cycles appear to be responsible for the warming first experienced when the earth comes of a glacial period. Increased warming appears to occur due to greenhouse gases. This explains the lag between temperature increase and CO2 concentrations. Presumably it takes hundreds of years for the oceans to warm and release CO2. CO2 and methane released from thawing tundra presumably also have an effect. Methyl hydrates releaseing methane could be another factor. The melting of ice reducing the earth's albedo is also another effect.

This is correct. However, as water freezes it also releases co2. Take can of your favorite carbonated beverage and freeze it. The ice crystals occupy more space as a crystal matrix is formed and the co2 moves out of solution. Open the can and enjoy the syrupy spray. There is a range of temperature and pressure that co2 has maximum solubility which concides with temperature and pressures that are common on this planet. This is an example of another feedback loop that enters into the equilibrium of the climate.

This also why I think the ice core samples will systemically show low co2 percentages.

[pghnative]

There is a range of temperature and pressure that co2 has maximum solubility which concides with temperature and pressures that are common on this planet. There is no magical "range" of temperature and pressure common on this planet at which CO2 has maximum solubility. CO2 solubility in liquid water increases as the temperature decreases. CO2 solubility increases with increasing partial pressure.


This also why I think the ice core samples will systemically show low co2 percentages.Except that the ice core samples are being analyzed for CO2 levels in entrapped air, not in the ice itself. Why would the entrapped air be systematically low? (If anything, if the water released CO2 as it froze, the entrapped air could be argued to be enriched in CO2.)

[jlhredshift]

There is no magical "range" of temperature and pressure common on this planet at which CO2 has maximum solubility. CO2 solubility in liquid water increases as the temperature decreases. CO2 solubility increases with increasing partial pressure.
I did not say "magical", but the ranges of solubility are common on this planet not Mars or Venus, but possibly on Jupiter, Saturn, Europa, etc. Since the pressure at the surface is reasonably constant on the big scale, pressure has less impact than temperature, but there is some effect.


Except that the ice core samples are being analyzed for CO2 levels in entrapped air, not in the ice itself. Why would the entrapped air be systematically low? (If anything, if the water released CO2 as it froze, the entrapped air could be argued to be enriched in CO2.)

Well, not all would be trapped, some would escape back to the atmosphere. The difficulty would be to put a precise quantitative number to it with so many of the extant conditions at the actual time of ice formation being unknown.

[grant hutchison]

It's worth realizing that the air trapped in the glacier was nowhere near the surrounding glacier ice during the actual freezing process, and couldn't therefore have participated in any gas exchange arising from cooling and freezing.
The water forming the glacier froze as snowflakes in clouds high overhead, and accumulated as snow. The snow and the ground level air it trapped were subsequently compressed together to form clear glacier ice shot through with bubbles.
All these processes are very well understood.

Grant Hutchison

[pghnative]

I did not say "magical", but the ranges of solubility are common on this planet not Mars or Venus, but possibly on Jupiter, Saturn, Europa, etc. Since the pressure at the surface is reasonably constant on the big scale, pressure has less impact than temperature, but there is some effect. You misunderstand my use of the term "pressure". I'm referring to the partial pressure of CO2 in the atmosphere. As the concentration (aka ppm, but in units of force per area) of CO2 increases, so does it's solubility. The total pressure (including O2, N2, etc.) is largely irrelevant. And I still maintain that Earth temp/"pressure" are not special with regard to solubility. Earth temp/pressure is special in allowing water to exist as both solid and liquid, but otherwise there isn't anything about Earth conditions that "maximizes" solubility.


Well, not all would be trapped, some would escape back to the atmosphere. The difficulty would be to put a precise quantitative number to it with so many of the extant conditions at the actual time of ice formation being unknown.You don't need to be quantitative to respond to my comment. You said that low solubility of CO2 in ice would cause ice cores to give false low readings. I gave a succinct mechanistic answer to explain why that was bunk. And now you dodge my response by saying "oh, but the CO2 would escape later". Which is it? Was there less CO2 in the ice core to begin with? or did it escape later?

Or do you just agree with any hypothesis, so long as it discredits ice core data?

[jlhredshift]

It's worth realizing that the air trapped in the glacier was nowhere near the surrounding glacier ice during the actual freezing process.
The water forming the glacier froze as snowflakes in clouds high overhead, and accumulated as snow. The snow and the ground level air it trapped were subsequently compressed together to form clear glacier ice shot through with bubbles.
All these processes are very well understood.

Grant Hutchison

This is correct as far as the original source of the water and air is concerned and it is also true that whatever air is trapped in the snow portion would contain representative ratios of atmospheric gasses nomatter how little is trapped. I think that at the boundry layer between snow and ice there is opportunity for preferential outgassing of co2. I am currently seeking the paper/article wherein I first read this idea and will have to get back to you. However, I will point out that compaction and transition phases induce liquifacation at boundry locations, therefore an opportunity for outgassing.

[grant hutchison]

Air also circulates through the superficial snow layers as firnification proceeds (during which the surface processes you've alluded to dismantle the original snowflakes and turn them into an amorphous open network of ice).
So, again, the trapped air bubbles have no "memory" for firnification, any more than they have for the original freezing. They simply become isolated as plastic movement of the surrounding ice eventually nips off their air channels with increasing pressure.

Grant Hutchison

[jlhredshift]

Air also circulates through the superficial snow layers as firnification proceeds (during which the surface processes you've alluded to dismantle the original snowflakes and turn them into an amorphous open network of ice).
So, again, the trapped air bubbles have no "memory" for firnification, any more than they have for the original freezing. They simply become isolated as plastic movement of the surrounding ice eventually nips off their air channels with increasing pressure.

Grant Hutchison

I have a problem with "all" and "never". So, are you saying there is "no" opportunity for co2 reduction(by number not chemical process)?

[grant hutchison]

I have a problem with "all" and "never". So, are you saying there is "no" opportunity for co2 reduction(by number not chemical process)?I didn't say "all" or "never". I just pointed out what seemed to me to be some quite significant and potentially misleading omissions in your discussion of carbon dioxide trapping.
Think of it as a supplement. :)

Grant Hutchison

[jlhredshift]

I didn't say "all" or "never". I just pointed out what seemed to me to be some quite significant and potentially misleading omissions in your discussion of carbon dioxide trapping.
Think of it as a supplement. :)

Grant Hutchison

Thank you, I did not intend to be misleading, but I am writing on the fly. In earlier posts I had said that I thought that the co2 readings would be systemically low (no quantification) and hard to pin down quantitavely, I will hold by those statements adding that I think that the difference in ppm is probably only a few or a couple of ten ppm. And further clarifying in saying that this probably unavoidable and no disparagement to Petit,et. al.

(and just as a side note- I think the study of the trapped Lake Vostock under the ice core drilling sites could be thought of as a prelude to Europa.)

[grant hutchison]

I will hold by those statements adding that I think that the difference in ppm is probably only a few or a couple of ten ppm.But you are, then, going to need to tell us exactly why that should be, and why people who spend their lives analysing ice cores have missed or misunderstood the mechanism you describe.
Otherwise we might not find your case persuasive.

Grant Hutchison

[jlhredshift]

But you are, then, going to need to tell us exactly why that should be, and why people who spend their lives analysing ice cores have missed or misunderstood the mechanism you describe.
Otherwise we might not find your case persuasive.

Grant Hutchison

Well, my numbers come from Petit, et. al.
[/QUOTE] The overall accuracy for ch4 and co2 measurements are +- 20p.p.b.v and 2-3 p.p.m.v. respectively.[/QUOTE]

Now they say +- and I say minus on the logic that some co2 has escaped. The upper limit of 20 ppm is a guess which depends on the environment of the firnification process, which is unknown and variable from point to point. Plus, compaction blends many seasons together and the resolution is 950 yrs.
I do not think they missed anything. I do not think they could present these ideas in their paper if they had them (I do not know), but I can postulate them here. As to whether I am persuasive is not important, but those who read these thoughts may think about the possibilities and view the data with an open mind for it is they, not Petit, et. al. that is my audience. Quite frankly I would relish in being wrong, or right, for then we would know something new. And Grant, keep poking me, nothing wrong in that.

JLH

[grant hutchison]

Now they say +- and I say minus on the logic that some co2 has escaped.They say plus or minus because those are their experimental limits of accuracy. They're giving their best estimate of the correct figure, and error bars. The farther you get from the central figure, the less likely your guess is to correspond to the true nature of the gas they sampled; the error bars allow you to estimate how unlikely your guess has become, if you know what sort of error bars they are.
If Petit et al. thought the figure was really lower, they'd give a lower figure, and similarly symmetrical error bars either side of that.

Now, if you're claiming that their estimate is inaccurate, then their error bars have no relevance to your estimate, so there's really no sense in trying to claim their error bars as some sort of support for your hypothesis ("... my numbers come from Petit, et. al.").

What you need to tell us is why you think CO2 escaped, what route it used to make its escape, and why the ice-core scientific community has so far missed whatever mechanism you've identified.

Grant Hutchison

[jlhredshift]

They say plus or minus because those are their experimental limits of accuracy. They're giving their best estimate of the correct figure, and error bars. The farther you get from the central figure, the less likely your guess is to correspond to the true nature of the gas they sampled; the error bars allow you to estimate how unlikely your guess has become, if you know what sort of error bars they are.
If Petit et al. thought the figure was really lower, they'd give a lower figure, and similarly symmetrical error bars either side of that.

Now, if you're claiming that their estimate is inaccurate, then their error bars have no relevance to your estimate, so there's really no sense in trying to claim their error bars as some sort of support for your hypothesis ("... my numbers come from Petit, et. al.").

What you need to tell us is why you think CO2 escaped, what route it used to make its escape, and why the ice-core scientific community has so far missed whatever mechanism you've identified.

Grant Hutchison

I understand error bars. The process I gave in an earlier post, but, here goes again. At the boundry of the firification process liquids exist. Co2 can escape and I have not claimed they missed anything. If they can not quantify it how can they report it which is my point.

Here is the problem, I remember from somewhere that co2 escapes faster than o2 and N from solution. If I am wrong tell me now and I will desist.

[grant hutchison]

I understand error bars.I can only say that it seems very much otherwise from what you've said. You wrote "Well, my numbers come from Petit, et. al." and quoted their error bars. Those number have no relevance at all to your claims: they're only relevant to the measurements Petit et al. reported. The measurement errors they report can't constrain a systematic bias which you claim they can't quantify.


At the boundry of the firification process liquids exist. Co2 can escape ...Escape from the liquid? In which case it escapes into the "trapped" air, which is in direct contact with the atmosphere. This would seem to locally increase the carbon dioxide concentration in the "trapped" air, but as we've already discussed, the superficial firn is well ventilated, so its internal gas reflects the gas concentrations in the ambient atmosphere. Those thin liquid layers in the firn which you've mentioned are therefore able to equilibrate their dissolved gas tensions with the ambient air.


If they can not quantify it how can they report it which is my point.Of course they can quantify such gas movements: people have been studying firn cores for fifty years, and have identified all sorts of interesting processes in the deep firn. They're not just dumbly making assumptions about the equilibration of trapped air with ambient air, they've measured it.

Grant Hutchison

[jlhredshift]

OK Grant, You can bust me on semantics and hurried writing, but it comes down to this. I will refer to an earlier post, So, you are saying that no co2 escapes at all?
And I am not attacking or saying anyone got it wrong.

[grant hutchison]

OK Grant, You can bust me on semantics and hurried writing ...I'm not busting you on semantics; if I'm busting you at all, I'm busting you on physics. And you and I have been matching post for post for a while now: why should "hurried writing" give you some sort of debating "Get Out Of Jail Free" card? Do you think I've had the opportunity to prepare this stuff a week in advance?


but it comes down to this. I will refer to an earlier post, So, you are saying that no co2 escapes at all?I'm saying everything we've discussed so far simply sets up conditions under which the "trapped" air and surrounding ice in the firn can equilibrate partial pressures with the ambient air over the glacier. Carbon dioxide will move down its own partial pressure gradient, and that might involve diffusing into the atmosphere, or it might involve dissolving in a liquid layer in the firn.

If a liquid layer is in equilibrium with the "trapped" air, which is in equilibrium with the outside air, how can carbon dioxide "escape" in a way that biases the trapped air sample relative to the ambient air?
I'm just asking for you to describe that mechanism.

Grant Hutchison

[jlhredshift]

OK, Grant. The mechanism would be that out on top of a glacier things are not in total equlibrium, variableness would be the rule, cracks in the glacier, it would not be labratory situation, stuff happens, all of the co2 would not be captured. Compression would smooth out the irregularities, there is no way that you could be sure that the sample was truly representative of reality. And the numbers reported I am sure are as accurate as the investigators could make them, but that is not my point.

Now, who knows, after we have a hundred drill sites I may be proved wrong. A tme machine would work equally well, but that's another thread. Come on man, nothing is perfect, that's all I'm saying.

To me the 2ppm as a lower bound was acceptable, which is really saying that they were dead on.

Now I must go to work, we'll talk later. Have a good night Grant and good work.

[Ronald Brak]

We can check how air bubbles compare to vary accurate direct atmospheric readings for bubbles fromed within the past fifty years or so. This would demonstrate if there are any changes in the composition of gas when the air bubbles are formed. I'm sure this has been done.

[grant hutchison]

OK, Grant. The mechanism would be that out on top of a glacier things are not in total equlibrium, variableness would be the rule, cracks in the glacier, it would not be labratory situation, stuff happens, all of the co2 would not be captured.I'm sorry to go on about this, but this isn't a mechanism: it's a bit of handwaving that could equally be deployed to support an up-bias, a down-bias or an increased scatter.


Now, who knows, after we have a hundred drill sites I may be proved wrong.We've got your hundred drill sites, many times over, for the processes of snow deposition and firnification. This is old science.


To me the 2ppm as a lower bound was acceptable, which is really saying that they were dead on.So you're accepting their precision, but suggesting that their accuracy is slightly disturbed by a systematic bias that you can't quite explain, but somehow know the direction and magnitude of?

Grant Hutchison

[jlhredshift]

correct

[grant hutchison]

correctOK. Glad we've got that sorted out.

Grant Hutchison

[GOURDHEAD]

On top of this earth's orbit can vary from an eccentricity of almost zero to to almost 0.05 due to the gravitational influence of other planets (mainly Jupiter). Thanks Ronald for the review of the Milankivich cycle effects which seem to agree with what others have said and with which I have no disagreement. However, I feel the mosasaur in the swimming pool is being ignored by those who keep glossing over the assumed change in the eccentricity of the Earth's orbit other than to declare that it happened. The gravitational effects of Jupiter and indeed all of the gas giants taken together don't seem to point to 100 ka and 400 ka cycles of eccentricity variation. Also, I would be astonished if there is an analysis of the chaotic multi-body solar system that would produce regular 100ka and 400 ka cycles of eccentricity variation.

Is it only an orbital shape change, or is energy transfer assumed?

[Tim Thompson]

Also, I would be astonished if there is an analysis of the chaotic multi-body solar system that would produce regular 100ka and 400 ka cycles of eccentricity variation.
Reference my own post #264 (http://www.bautforum.com/showpost.php?p=797856&postcount=264) in this thread. The Berger, Loutre & Laskar paper (Stability of the astronomical frequencies over the earth's history for paleoclimate studies (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1992Sci...255..560B&db_key=AST&d ata_type=HTML&format=&high=44739db64323919)) addresses the matter of stability & chaos that you raise here. Also see ...

A long-term numerical solution for the insolation quantities of the Earth (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004A%26A...428..261L&db_key=AST &data_type=HTML&format=&high=4366fa465131941); J.Laskar, et al., Astronomy and Astrophysics, 428: 261-285, Dec 2004.
Successive Refinements in Long-Term Integrations of Planetary Orbits (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003ApJ...592..620V&db_key=AST&d ata_type=HTML&format=), Varadi, Runnegar & Ghil, Astrophysical Journal, 592(1): 620-630, July 2003.
The limits of Earth orbital calculations for geological time-scale use (http://www.journals.royalsoc.ac.uk/(rn1fk155mx1fdv45atkxhmaw)/app/home/contribution.asp?referrer=parent&backto=issue,2,14;journal,90,125;linkingpublicatio nresults,1:102021,1), J. Laskar, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 357(1757): 1735-1759, 15 July 1999.
Marginal stability and chaos in the solar system (Lecture) (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996IAUS..172...75L&db_key=AST&d ata_type=HTML&format=&high=4366fa465104620), J. Laskar, 1997.
Large scale chaos and the spacing of the inner planets (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997A%26A...317L..75L&db_key=AST &data_type=HTML&format=&high=4366fa465104620), J. Laskar, Astronomy and Astrophysics 317: L75-L78, Jan 1997

Most of the papers, especially the more recent, are not readily available online, so you have to find them the old fashioned way. Nevertheless, these papers dirfectly address chaos & stability, and the 100,000 year eccentricity periodicity. They also show the evolution of thinking over the few years spanned by the papers. Left on their own, the chaotic nature of the inner planet orbits would make them unpredictable beyond 30 or 40 million years. But the outer planet orbits are stable for much longer periods. Just as the torque of the moon stabilizes the chaotic obliquity of Earth (Laskar, Joutel & Robutel, 1993 (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993Natur.361..615L&db_key=AST&d ata_type=HTML&format=&high=4366fa465104620)), the torque from the more stable outer planets stabilizes chaotic motions of the inner planets. The result is that billion year integrations are stable.


Is it only an orbital shape change, or is energy transfer assumed?
I don't see, offhand, how it would be possible to alter the orbit of a planet, without transferring energy and/or momentum to do it.

[Ken G]

I think GOURDHEAD's point is that of the constants of motion of a simple orbit, some are easier to change than others. The location of the periastron is quite easy to change, the eccentricity (i.e., angular momentum) a little harder, and the total energy harder still. I don't know if that's really true, but I've heard it. Ask Celestial Mechanic, but my guess would be that the Milankovich cycles don't change the total energy of the Earth's orbit.

[xVLA]

Like which Wiki article? I've read several and more...
xVLA

[Disinfo Agent]

Isn't that essentially an ad hominem attack?

It is always bad form to use the fallacy of argumentum ad hominem. But there are some cases when it is not really a fallacy, such as when one needs to evaluate the truth of factual statements (as opposed to lines of argument or statements of value) made by interested parties. If someone has an incentive to lie about something, then it would be naive to accept his statements about that subject without question.

Logical Fallacies and the Art of Debating (http://www.csun.edu/~dgw61315/fallacies.html#Argumentum%20ad%20hominem)You don't even need to look for an incentive for the person to lie deliberately. A strong incentive to believe the falsehood is enough.

Besides, xVLA did not say (http://www.bautforum.com/showpost.php?p=796399&postcount=254) that global warming skeptics are wrong because many of them have a vested interest in the matter; only that what they say should be "taken with a grain of salt", which doesn't necessarily mean dismissed offhand, I think.

[xVLA]

That's what I said and what I meant.

xVLA




Besides, xVLA did not say (http://www.bautforum.com/showpost.php?p=796399&postcount=254) that global warming skeptics are wrong because many of them have a vested interest in the matter; only that what they say should be "taken with a grain of salt", which doesn't necessarily mean dismissed offhand, I think.

[Disinfo Agent]

I figured as much.