This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
The CO2 concentration lags behind temperature by centuries in the glacial-interglacial cycles, so clearly CO2 does not cause temperatures to rise, temperatures cause CO2 to rise.
Answer:
A close examination of the CH4, CO2 and temperature fluctuations recorded in the Antarctic ice core records does in fact reveal that yes, the temperature moved first in what is, when viewed coarsely, a very tight correlation. But what it is not correct, is to say the temperature rose and then hundreds of years later the CO2 rose. These warming periods lasted for 5,000 to 10,000 years (the cooling periods lasted more like 100,000 years!) so for the majority of that time (90% and more) temperature and CO2 rose together. This means that this remarkably detailed archive of climatological evidence clearly allows for CO2 acting as a cause for rising temperatures while also revealing it can be an effect of them.
The current understanding of those cycles is that changes in orbital parameters (Milankovich and other cycles) caused greater amounts of summer sunlight to fall in the northern hemisphere. This is actually a very small forcing, but it caused ice to retreat in the north which changed the albedo. This change, reducing the amount of white, reflective ice surface, led to increasing the warmth more in a feedback effect. Some number of centuries after that process started, CO2 concentrations in the atmosphere began to rise and this also amplified the warming trend even further as an additional feedback mechanism.
You can also go here for a discussion by climate scientists of exactly this question but with greater technical detail and full references to the scientific literature.
So, it is correct that CO2 did not trigger the warmings, but it definitely did contribute to them, and according to climate theory and model experiments, greenhouse gas forcing was the dominant factor in the magnitude of the ultimate change.
One warning that this gives us for the future is that we may well see additional natural CO2 come out of the woodwork as whatever process that took place repeatedly over the last 650K years begins to play out again. The likely candidates are out gassing from warming ocean waters, carbon from warming soils and methane from melting permafrost.
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
"CO2 Lags Not Leads" was first published here, where you can still find the original comment thread. This updated version is also posted on the Grist website, where additional comments can be found, though the author, Coby Beck, does not monitor or respond there.
So, let me get this straight in my head: each time, the temperatures started to increase due to some driver (let's call it, say, the primary driver) about which we know little, except that it definetely was not CO2 levels, then, a few centuries after this, CO2 levels started to rise along with it. Then their levels both decrease roughly in tandem.
A schoolboy scientist applying Occam's Razor would deduce from this that the primary driver is pulling up the CO2 with it, the CO2 is then no doubt increasing the global temperature due to the greenhouse effect, but as the effect of the primary driver wanes, the temperature and CO2 levels wane with it, and we get back to where we started. I would also come to this conclusion, though I am not a schoolboy (I have an engineering phd).
I don't see what the problem with this is. It doesn't even contradict the main claims of AGW. But both here and on real-climate, there are these unnecessary and convoluted arguments about feedback - feedback! even though we agree that the primary driver is unknown, we can calculate feedback? what!!
So if you're aim here is to have people answer climate sceptics by having them insist that everything, everywhere, is evidence for AGW - and that nothing against it should be acknowledged as even maybe a problem, and everything neutral should be twisted to be a positive argument - then you're doing well.
Hi frank,
your description is roughly in line with what I say above, so I'm not sure what the beef is..? BTW, the primary driver is known to be milankovich cycles.
The evidence for feedbacks comes in the details of the forcings required to move the temperature so much, orbital forcing is far too small, but factoring in the CO2 and CH4 rise and the changes in albedo get us most of the way there. So the idea of feedbacks comes right out of the data, it is not thrown in there on a whim.
Thanks for the comment!
"So, it is correct that CO2 did not trigger the warmings, but it definitely did contribute to them, and according to climate theory and model experiments, greenhouse gas forcing was the dominate factor in the magnitude of the ultimate change."
No I don't think we are in complete agreement. I said that the simplest explanation is that the CO2 concentration is following (or determined largely by) the temperature; you are saying that it is (a few hundred years after the trigger) the dominant factor in the magnitude of the temperature, which is the opposite.
So you are claiming that much of the period of warmth was due to CO2, suggesting that the primary driver stopped after a few hundred years and temperatures then would have dropped were it not for CO2. This seems convoluted to me, to say the least - your explanation seems plausible for sure, but plausible is some way from verified, even by "climate theory and model experiments".
There is an even bigger problem with Coby's forcing theory: if CO2 became the main driver, then why did the historical warmings stop, reverse, and go back down each WHEN STILL IN THE PRESENCE OF THE HIGHEST C02 LEVELS?
Hmmm...a one-way forcing...that's certainly a new one in the annals of science.
Rob:
"Coby's forcing theory" - ! very flattering, but I have to confess it is not my own, it is simply the best (only?) hypothesis that exists in the climate science community at the moment. The warmings presumably stopped because the sources of CO2 ran out or slowed. The temperatures dropped again via an orbital forcing trigger and reversal of the warming mechanism. So, not one way (though why that should be ridiculous is beyond me), and didn't I describe that in the post??
The primary driver does not need to stop to be overwhelmed by another. Yes, plausible is ot verified, but how do you propose we do that, aside from model experiments based on theory? It is not an option to recreate the world in a test tube and run a 100K yr experiment!
Rob clearly stated the fundamental problem with the standard (here, RealClimate and others) AGW explanation of these lags - if CO2 did in fact take over, what made it stop?
If a strongly cyclic process was the initialiser for each of these temperature rises, then a non-cyclic (or certainly far less cyclic) process (CO2 levels) took over the temperature regulation for while, why would it wane back to the levels before the start of the current cycle each time? ie. behave as if it were cyclic WITH THE SAME PERIOD AS THE MILANKOVITCH CYCLES!
Seems a bit of a stretch to me. Surely the ......you know, I just cannot summon the energy to point out how absurd this is. Anyone who can't see this is willfully suspending their common sense.
And sorry Coby but vague and tentative statements like "it is simply the best (only?) hypothesis that exists in the climate science community at the moment." and "The warmings presumably stopped because the sources of CO2 ran out or slowed." simply reinforce this - it's clear EVEN YOU don't really think it's true.
When people who propose I change my life to prevent us all being barbequed can formulate arguments, I'll start paying attention to the warnings.
frank, see this article. Sorry, but incomplete knowledge of the past does not mean we can not know enough about today. We may never know the details of the recent glacial cycles, the data sources are limited and indirect. The general mechanism I have described above is completely consistent with what we know about today, the existence of unknown details is not an excuse to continue our dangerous and irreversible planet-wide experiment.
I don't need to read beyond the objection part of that link, as I don't remember arguing that "incomplete knowledge of the past does [means] we can not know enough about today" and, as I have phd in engineering, I certainly don't need to be told why this is so. You might try attending to the points raised and not imagined ones.
In any case, as I didn't argue that point, this incomplete knowledge of the past you are referring to is presumably your incomplete knowledge of the reasons for the CO2 lag behind the temperature. Thanks for confirming that you are not in fact sure of it, which was my original point, and are just theorising. I work daily on a complex system (a machine) and guessing what is going to happen after a change is all fine and dandy, but we're wrong as much as right. And we built it. And it is WAY less complex that the climate. But, please, go ahead with your unfalsifiable thought experiments and use the "results" to tell people how to live their lives, if that's how you like to spend your time.
And on your final words, I think I'll bow out from bothering with this website at all ie.
"The general mechanism I have described above is completely consistent with what we know about today, the existence of unknown details is not an excuse to continue our dangerous and irreversible planet-wide experiment."
Hmmm. A theory pushed because it is "completely consistent" with the facts. Can't even be bothered with discussing that.
And "dangerous and irreversible planet-wide experiment". You are just advertising that you consider this to be a done deal, that there is no case to answer, that the mere request for evidence shows that I am a...there's a word for this... I know - heretic.
I don't get it. 800 years is a lot. CO2 was not a mayor climate driver in the past (cause if so was the heating would never have stopped, and it has very logical, physical reasons, such as the oceans releasing more soluted CO2 in warmer periods than in cold). If it was not a mayor driver of climate change in the past (but more a product of it), why would it be now? Does properties of CO2 change over time? I didn't think so anyway.
All argumentations about CO2 heating the earth enormously goes beyond logics... I am not in favor of releasing CO2 into the atmosphere, since it will have consequences, though not such as described by Al Gore.
800 years is a lot. We can measure year by year, so what is that junk about not being precise....
//HS
(In the past scientists new that the Earth was spinning around the Sun, but anyone claiming this would be killed by the church. The environmental movement has now become the religion of old. They claim the debate is over, but it is not.)
Hi HS,
You last sentence is so ridiculous it almost stopped me from answering you at all. But I will make a couple of points for you.
"800 years is alot", well this depends. In the context of a 15,000 year warming trend or a 100,000yr cooling trend it is not.
Just because a feedback loop exists does not mean it can never stop, so the fact that we did not warm until the planet melted does not mean that warming planet and rising CO2 can not interact is described in my post.
Today is unique in the history of the planet, so I would caution you about determining what is possible by looking only for examples in the past. However, the PETM event is actually a very fine example in its likely similarity to today.
Al Gore did not invent AGW theory. I recommend getting your science from the IPCC report, this one is out of date but still fine for the basics:
http://www.grida.no/climate/ipcc_tar/wg1/index.htm
The "junk" about being precise is the reality of the ice cores. The resolution is not annual when you go farther back in time. Some of the data points represent time periods thousands of years apart. You can see one of the data files here:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/co2.txt
Thanks for the comment!
Why is this so difficult to understand?
When it comes to the recent Ice Ages, CO2 provides a magnification effect. So, the Milankovich cycles provide the primary effect, but that effect is magnified by the CO2 response and effect. This works both on warming swings and on cooling swings.
We can calculate the magnitude of the effect on the climate from the Milankovich cycles themselves, and that effect is too low, but the Milankovich cycles match the periodicity of the Ice Ages. So clearly the Milankovich cycles are the cause (they can't be an effect, since there's no possible mechanism for the Earth's climate to influence its orbit), but there must be feedback loops which magnify the effect of those cycles.
Lamont - what you've said isn't difficult to understand at all, and I could almost agree with you.
You say that the increase in temperature is too much to be due to the earth's orbit alone, and you say that the difference must be due to CO2. Can you say how you know this? What if there was some other poorly understood effect that was raising the temperature and the CO2 was then rising in response to that, not an unreasonable scenario? How do you know this is not the case?
Further, if we put that question aside and assume the change is in fact due to CO2, what was the actual temperature change (beyond that calculated to be due to the MC) and corresponding change in CO2 concentration to go with it please?
If in this scenario, as you say, the CO2 acts only as a magnifier - and not a primary driver - of the temperature, then I would ask: if it is going to start raising temperature significantly in the near future, what effect is it going to piggy-back? What effect is it giong to magnify?
Or is it going to cause problems alone? In that case, can you demonstrate how what you describe - CO2 magnifying an existing effect - is relevant to the current problem? I'm not saying it isn't, I'd just like to explain how.
I'm no scientist but I understand the basic theory and don't understand why others don't.
The Milankovich cycles were the primary effect that then caused CO2 levels to rise which resulted in further temperature rises. The key point is that an increase in CO2 levels caused temperatures to rise but it needed a primary driver. It seems completely plausible that human activity has now become the primary driver by dramatically increasing the levels of CO2 and other greenhouse gases over a very short period of time that is out of sync with the Milankovich cycle.
A complex area I know, but the earths climate is changing and for people to suggest that human activity has had NO effect on it at all seems to ignore our dominance of the planet.
Marcus one of the reasons that there is confusion is that language is being mangled and terms are used without regard to their precise definition. I dont even really disagree too much with what is being said, but I do a bit and the first thing to do is to be precise. Statements like the earths climate is changing and for people to suggest that human activity has had NO effect on it at all seems to ignore our dominance of the planet. are not helpful. The earths climate has always been changing. And suggesting we dominate the planet with regard to climate is just absurd. Im sure you didnt mean that the way it came out but it shows that an injection of clarity is required before we arrive at a conclusion here.
And one other point to clear up is that anyone who suggests that CO2 is not a greenhouse gas and/or does not affect the temperature at all is not, in my view, to be taken seriously given our current knowledge it is a waste of time to often have to point out that I am not this straw man when I have raised actual points that I would like addressed. The key question is whether the effect of human CO2 is significant/measurable given the other external forcings and the natural internal variation of the climate - I suggest that it is not.
The Milankovich cycles were the primary effect that then caused CO2 levels to rise so MC raised the temperature and then CO2 rose in response to to this (increase in rate of release of C02 from oceans or whatever it was). Then you say The key point is that an increase in CO2 levels caused temperatures to rise but it needed a primary driver so the temperatures only rose initially only because of the MC (the primary driver). Then many hundreds of years later there was a consequent increase in C02, which rose the temperatures further and maintained this for thousands of years? This appears to be what you are saying is this correct?
No doubt that there was a temperature increase due to this increased CO2 and the greenhouse effect. And you are saying that we have replaced the MC in this, and are raising the C02 levels in the same way.
I agree that much of this sounds plausible but things this complex are not resolved on that basis. What figures are you working from? Can you point out a particular rise which is due to the combined effect of the MC and the CO2, and tell me what part of the rise is attributable to MC and what to C02? To have come to the firm conclusion that you have, you must have done or seen this calculation already.
Also, one of the rises in question lasts around a few thousand years and the claim is that after a few hundred years this is due ONLY to C02. This is what I have read on real climate and appears to be what you are saying.
http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/
What seems remarkable to me is that this CO2 induced warming seems to die down and then reappear in period with the MC. If, as you say, the warming after the initial MC warming (after 800 years or so) is due to CO2 ONLY, then this should at this point be independent of the MCs period no? That it is not suggests to me that the rise AND FALL of this process is driven by the MCs and so is not only due to CO2. So, in the absence of the extremes and the large temperature forcings (at least 800 years worth and I seek proof it is no longer than this) associated with the MCs, it seems a stretch to compare that behaviour to the present day. If you think it is directly comparable, please can you explain how.
Or, maybe Im wrong and it is independent of the MCs. Maybe the CO2 induced warming just lasts a finite amount of time and this just happens to be less than the MC period and all record of it is wiped by the time the next MC-induced ice age arrives, and so I am mistaken. In that case, why does it last this amount of time? What brings the temperature and C02 levels down? Noone seems to be in any doubt at all ever - as to what is happening when the temperature rises, so I presume the whole process is well understood can someone tell me (with equal certainty or explain where they are not certain) why this period of warming is 4200 years ish. Why not 10,200? Or 2,200?
I have a few questions,
If c02 rise lags temp rise by X number of years and over the last 100 hundred years c02 has risen by say 100ppm, would it be fair to say that some of this rise is due to the c02 lag? If so then how much of the 100ppm is due to lag and how much is due to human activity? This is an important question and i doubt any AGW proponent will be able to answer.
Also correct me if i am wrong but the MC's in effect control the amount of energy the earth recieves from the sun yes? Which then cause warming or cooling of the planet. Therefore if the suns output varied would this not be seen on Earth as the same thing?
Do the models take into consideration variations in the Earth's orbit? I seem to recall the IPCC dismissed the suns effect on Earth's with utter contempt so i doubt it very much. Therefore how can you base a theory on warming periods beginning with variations in the suns output/effects on earth but then completely ignore the very same thing as a driver of our current climate.
As always AGW proponents lack the consistency required to have a worth while debate.
Fortunately, it is not necessary to guess by poor analogy with the distant past, we can analyze directly the CO2 in the atmosphere and identify the origin of its increase. Have a look at this article.
So, none of the observed increase is natural.
Milankovitch cycles do not change the amount of energy reaching the earth, only its seasonal and geographic distribution. The reason these cycles are not relevant today is simply because they operate on a scale of 10's of 1000's of years. I doubt the models that make the 100 year projections bother to put those calculations in, for the same reasons they do not include the evolution of the sun into a red giant.
The IPCC attributes about 15-30% of the early 20th century rise to solar influences, no contempt, just scientific studies. Since the 1950's there has not been a significant change. It is pretty clear you've never read an IPCC report for yourself.
If CO2 is the primary driver then wouldn't we see a consistent spike in the temperature's rate of increase once the CO2 levels began to rise? So, to be clear, if the MC is causing say a rate of increase of .1 degrees per 100 years wouldn't we see that jump to say .2 degrees per 100 years consistently once the CO2 level increases?
In the past,based upon ice cores, the min & max temps had CO2 levels of about 180ppm & 280ppm, respectively.
The current 385ppm does not have much of a rise in temps as the proAGWers claim. Therefore, that proves that CO2 is a very weak forcing GHG.
Hi Randall,
I'm not sure what you think the temperature rise has been but many independent lines of scientific investigation indicate it is about .8oC so far. As for what this says about climate sensitivity to CO2, the problem is that there is a large amount of thermal inertia in the system, so it is too early to use present day temperature observations as an indication of what 385ppm CO2 will ultimately do to the climate.
So you are saying that at first, the horse pulls the cart. Once they are rolling, the horse jumps on top of the cart and the cart pulls the horse. I get it.
Vespacian - yes, that is what I am saying. But your analogy is poor because the horse-cart scenario can't happen that way and it is contrived to make the concept sound ridiculous. Try to think of a situation where there is a real feedback effect, there are many. It is not so difficult to understand.
The debate here is silly. There's no need to wonder if there might be a 'feedback mechanism whereby higher temperatures lead directly to more CO2.' That mechanism is known to anybody who took chemistry in high school. It's the fact that as a liquid heats up, less gas can be dissolved in it. Duh? Sputtering on about how CO2 also led to more heating (then didn't a few thousand years later, when things got colder) is illogical. CO2 didn't start the warming, and it didn't stop the warming. Did it contribute in some small way in the middle? Maybe. But it is not the root cause by any means. I don't know why this is so difficult. Warmer temperatures lead directly to more CO2 in the atmosphere. There's nothing surprising in the least about this. Stop trying to turn the relationship on its head.
Also: The thermal inertia idea has been discredited. There is no 'warming in the pipeline.' If there was, it'd be in the oceans. That is to say: the oceans temperature would 'lead' land temperature in the records. This is not the case, they track perfectly well with one another. There is no argument about temporal resolution here, the time scales are annual for both measurements.
"Did it contribute in some small way in the middle? Maybe."
Perhaps you can share with us your estimates in W/m^2 of the various contributing factors in the warming out of the last glaciation. How many W/m^2 did the orbital variation supply? Albedo changes? CO2 and CH4?
There is no need for us to rely on self identified ignorance (this is not meant as an insult, merely a reference to your admission that you don't know), the difficult scientific research has been done and there are fairly well constrained estimates of all of these factors (see the citations in the referenced RealClimate article), estimates that take into account well know physical properties, not silly out of hand dismissals of major factors.
Re thermal inertia: you have badly misunderstood what that concept is about. Thermal inertia of the oceans does not mean they warm first and then warm the atmosphere, it is merely a reference to the amount of time required to reach a new equilibrium temperature, kind of like how it takes time between turning on the furnace and feeling warmer. The oceans require a lot of heat energy to gain the 2 degrees we expect from the change in radiative balance. It will take some decades before they have finished warming, that is decades after the cessation of CO2 accumulation. The atmosphere will not warm any faster as conductiona dn convection ensure heat flows back and forth to and from the oceans.
Coby,
would it be correct to say that CO2 is the primary cause of today's warming, but that it has not in the same way been the primary cause of temperature changes in the past?
Hi Jonaton,
Yes, that is correct. Though GHGs have evidently been responsible for some previous dramatic climate changes, such as the PETM event and the Permian-Triassic extinction event.
Coby,
Maybe you could explain in more detail why CO2 is the primary cause of todays warming but was not the primary cause of warming in the past.
While you are at it, maybe you could explain why the CO2 levels post 1998 have continued to rise whilst the global temps have not. I was of the understanding that the AGW theory hinges on "as CO2 rises so will the temps" this is obviously not the case. Therefore please enlighten us on what is causing the planet not to warm post 1998 against ALL computer model predictions.
Crakar
Hi Crakar,
Please read this post.
GHGs have caused climate changes in the past, but not all, there are many factors that control the climate.
While you are at it, maybe you could explain why the CO2 levels post 1998 have continued to rise whilst the global temps have not.
Crakar, you've been making this claim like its going out of style lately. I'm curious why you think this one year is so significant, but disregard that the 2000's continues to be the warmest decade on record (every year post 2001 is in the top 10 list). It has been explained to you over and over again, and I really want to know why you discard these explanations and continue to believe that this disproves the theory.
No one has ever said temperatures will rise monotonically.
Adam,since 2002 temperatures have slowly fallen while CO2 has increased 4 %.In terms of AGW theory[only],please explain this observation.
timobrienwells -
Well, for one, I don't confuse weather with climate, so I don't draw long-term trends from short-term effects.
Climate in a narrow sense is usually defined as the "average weather," or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands of years. The classical period is 3 decades, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.
http://www.epa.gov/climatechange/glossary.html#Climate
But really, timobrienwells, you're getting your talking points wrong. Global warming stopped in 1998, remember!
Coby: I am frankly amazed that you can answer the question:
"would it be correct to say that CO2 is the primary cause of today's warming, but that it has not in the same way been the primary cause of temperature changes in the past?"
as posed by Jonathan with a "Yes", and not be led to think by simple logic that if CO2 was not the primary cause of temperature changes in the past, then perhaps it is also NOT the primary cause of temperature changes today? Alternatively, if you accept the presence of another unknown primary cause of temperature rise in the past, how do you know it is not active today?
This is very basic logic and scientific reasoning. If you cannot rule out some other cause, how can you assert that one cause is now dominant? Should we not try to find out about this other unknown cause first and understand it better?
And that is not even to mention the fact that from the ice core records of temperature cycles, temperature decreased by a few degrees C despite the fact that CO2 remained at a high level (about 250 ppm). How "dominant" a warming effect can CO2 have if it had little effect on the temperatures dropping in the past, or are you saying that the laws of physics have changed from 100000 years ago to now?
Perhaps it is time to think for yourself rather than rely on some supposed "consensus".
Coby,
Just two questions:
1. If once CO2 starts rising it is the primary driver, then why does it start cooling while CO2 is high? Why does CO2 lag warming and lag cooling. If it was as strong a driver as suggested, then once it got started, it would keep warming.
2. Where is this hidden warming in the pipeline? The Argo's project has shown that the sea's are not warming. If the sea are not warming then, where is this mythical warming in the pipeline.
But Adam,CO2 causes warming!And CO2 has risen 4% since 2002.
Temperatures have FALLEN since 2002.Why?
timobrienwells -
Because the relationship is not 1:1. We expect a long-term trend in increasing temperatures (climate), with short-term variation super-imposed over it (weather). That's why you have some years that are warmer than subsequent years. No one has claimed that global warming causes monotonically increasing temperatures.
So what Exactly is this 10 year "weather" that you speak of?How has it overcome the effect of CO2 and made temperatures fall?
Coby,
Your statement is wrong.
They did not rise together, to rise together implies they rose at the same time which they did not and have not. The facts are quite plain that CO2 lags climate change by 800-2500 years. CO2 rises after 16-25% of the warm period has passed and lowers after the same amount of time after the warm period ends. What is correct to say is 75-84% of the time climate is warm, CO2 levels are high also. This in no way indicates that they rose together, but rather shows that after a climatic temperature change, CO2 levels change.
The simple alternative theory for CO2 change due to climate change is that once warming starts, it takes time to warm the oceans. Once the oceans warm, the reduced solubility of gases in water causes the oceans to release CO2. On the other side, once cooling starts, eventually the oceans cool and solubility increases and Henryâs Law happens.
timobrienwells -
http://en.wikipedia.org/wiki/El_Ni%C3%B1o
timobrienwells -
How has it overcome the effect of CO2 and made temperatures fall?
It doesn't 'overcome' the effect of CO2 and other greenhouse gases, it's an additional input that causes fluctuations.
Generally:
Given signal A, a high-frequency, low-amplitude signal
and signal B, a low-frequency, high-amplitude signal
Superimposing A over B doesn't cause A to overcome B, but it does affect the value, causing local peaks and troughs.
http://www.aars-acrs.org/acrs/proceeding/ACRS1991/Papers/PS191-1_files/…
Look at the middle graph. You can clearly see a the lower frequency cycle (with peaks approximately at the vertical bars). Over this, you can see the high-frequency variation.
Hope this helps.
Vernon, if I lived 110 miles south of town and you lived 125 miles south of town and as you drove past my house I got in my car and drove alongside you, did we drive to town at the same time? Did you drive to town before I did? Would it be accurate to say "first Vernon drove to town and then Coby drove to town"?
Once more, this is not a valid example; you make the underlying assumption that those are two independent events. This is not supported by the historical record. The record shows that CO2 has only increased after the climate has increase for a length of time. Please point to a high resolution (temporal) record that shows that CO2 increase precedes warming. The only ones that I know of are ice cores that go back ~480,000 years and they all show that temperature changes leads CO2 changes.
You like examples, let use one that actually reflects the historical record; namely, a steam engine. The steam engine is sitting idle. You shovel coal into the fire box and the temperature goes up. After a while the amount of steam produced goes up, notice there is a lag. Once youâre done you stop putting more coal in the fire box and the temperature goes down. A while later the amount of steam produced goes down, once again a lag.
The steam (CO2) does not increase or decrease until the temperature changes. The temperature changes are based on the coal (climate driver). You keep saying and using examples where CO2 is independent from the temperature change. The climatic histories do not support that position.
Vernon, please just reread the article more carefully, especially not the last sentence. You are not contradicting anything in there in this last comment. The warming caused the increase in CO2, the CO2 caused the majority of the overall warming, though not the initial part.
That is what a feedback is (and no, feedbacks do not have to be runaway, they can as in this case, be self limiting)
Coby,
You have just made an assumption with no basis. The historical record shows that temperature peaks before CO2, it also shows that temperature drops before CO2 drops. You can say CO2 acts as a driver and causes it to get warmer, but you cannot point to any high resolution (temporal) record that shows that CO2 increase peak precedes the temperature peak. By this I am saying that the temperature peaked before CO2 peaked. If CO2 was a driver as you claim, then the temperature would not peak until the CO2 did.
Your making an assumption that is not supported by the historical record.
I will make my question simpler Adam.What "weather", specifically,has caused temperatures to fall since 2002?
Persistent La Nina`s have caused a stagnation of the background warming trend since 2002.
Coby,
I see your conceding that your argument was not founded on fact. Why not just remove this from 'how to talk to a skeptic', since your position does not have a scientific basis.
Vernon, please don`t confuse giving up on a dialogue with any particular visitor as abandoning my point of view. But I will give it a bit more effort here. You have changed your position, so can you please point to a source for us that shows temperature peaks earlier than CO2 peaks? It would save me the time, and surely as it is your claim you must have some easily interpreted graph or data handy, I don`t have time to dig through all the sources I have bookmarked. Thanks.
Coby, It is the Vostok ice core record, actually, from what I have seen, it is all the ice core records. Do I need to give you a link for the this? First, you say I have changed my position, I think not. Please show where my position has change.
My position has been that CO2 lags warming. You try to treat CO2 and temperature as two independent varible when the historical record clearly shows that temperature increases/decreases lead CO2 increases/decreases. You also say that CO2 is a strong driver and once the warming starts CO2 takes over. This is patently wrong. Back before they had as high a temporal resolution as they do now for the ice cores, your position would have been logical, however, they do and your not. If CO2 was a strong driver, then the temperature peak would be at the CO2 peak or after. The temperature peak is before the CO2 peak. This shows that CO2 is not the major driver and that there is no lag between the rise of CO2 and temperature.
Basically, like the Lorius Et al (1990) study that proposed the lag between CO2 and temperature back then, newer technology has allowed greater resolution and shows that your positon, like that paper, are not supported by the evidence.
Vernon -
If I may, I think you're operating under the erroneous assumption that CO2 is the only driver of temperature (or rather, that if CO2 were a driver, it would be the only one). Your claim seems to be based on the idea that there's only ever a single given source (or one extremely dominant one) for changing climate.
Here's a thorough explanation for the effect. I was going to try to summarize it for you, but I think you'll gain a lot by reading it fully.
http://www.realclimate.org/index.php/archives/2007/04/the-lag-between-t…
or here
http://www.newscientist.com/article/dn11659-climate-myths-ice-cores-sho…
Hope this helps.
Adam,
RC is not scientific proof of anything. There is no proof of any lag between CO2 rise and temperature. I read what RC had to say and strangely, they do not quote studies that prove that CO2 does not lag temperature. Do you know why they do not quote those studies, because there are none since the technology improved so that we have the resolution that shows that temperature changes precede CO2 changes.
Now the other point that Coby, makes is that CO2 takes over as the warming driver after the weak MC forcing start CO2 increasing. That only has one flaw, the climate record does not reflect this. If it did, the ice core record would show that the temperature would peak when CO2 did or if there really was a lag between CO2 increase and later warming, then the temperature would peak after the CO2 peak.
Neither of these things happens. What is shown is that a climate driver starts warming or cooling and after 800-2500 years, CO2 changes to follow the temperature. That is fact from studies.
So, thanks for offering to help but if you cannot point to an actual study, then it does not help. To quote, if it has not been peer reviewed then it is not science is what I most often hear.
Adam,
You say
But this contradicts what Coby says:
So you see, Coby's point is that CO2 becomes the primary driver, which the evidence does not support.
Coby,
are you still trying to find a study that shows that CO2 is the driver you claim that it is? Are ignoring me rather than admit that the historical record does not support your position?
Do I need to point you to the link for Vostok ice core data? It is:
http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_data.ht…
Still waiting for a scientific reply.
Hi Vernon,
Try this paper:
http://www.nature.com/nature/journal/v329/n6138/abs/329414a0.html
Coby,
That paper was written when you position would have been correct because the temporal resolution was not good enough to show that warming leads CO2. That is why the pre 1990s papers all used the ice cores to show that CO2 and temperature were in sync. Modern science shows that not to be true. That is why I gave you a link to the modern data so you could see for your self or look at modern charts that show CO2 lags temperatures.
If this is the best you have, then please retract your talking points on CO2.
Vernon -
How about this one:
http://www.nature.com/nature/journal/v412/n6846/abs/412523a0.html
Is there any point in continuing this discussion? Both Coby and I have shown you publications that explain this effect.
At this point, you're going to need to provide a citation for you claim that "modern science shows this not to be true." Saying "BUT JUST LOOK AT THE GRAPH" isn't going to cut it.
Adam,
Sorry it has taken so long to get back to you but RL happens. Anyway, I did read that study. I also read the studies that followed it. You say 'just look at the graph is not going to cut it." Why not? Coby makes the claim that CO2 is a strong driver, he even goes on to specify that CO2 takes over after the MC starts warming. The graphic is the simplest way to show that he is wrong. If he was right, then the temperature peak would happen after or with the CO2 peak. It clearly does not.
Anyway, I went and read up on the studies, including the one you pointed to. While the study is right that there is a high correlation between temperature and CO2 but that does not mean that CO2 is the cause.
Lüthi et al (2009)High-resolution carbon dioxide concentration record 650,000â800,000 years before present clearly shows that temperature precedes CO2 and that temperature peaks before CO2.
http://www.nature.com/nature/journal/v453/n7193/full/nature06949.html
Your right in that that study shows that there is correlation between CO2 and temperature but that the newer studies show still show that temperature leads CO2.
This comes back to my point. Namely that CO2 was not and never has been major driver of temperature change in the high resolution record (ice cores).
Here are some other studies to look at if you want.
http://pages2005.org/products/newsletters/2009-1/special%20section/scie…
http://www.cspg.org/conventions/abstracts/2008Gussow/029.pdf
Adam,
I addressed your both your questions and your points. So, are you conceeding?
Coby,
You said "don`t confuse giving up on a dialogue with any particular visitor as abandoning my point of view." So I am not asking if your conceeding but rather do you have anything that supports your position? Where is the science that supports your position?
Namely, that after the MC "weakly" starts warming and temperatures rise, CO2 takes over as the dominate climate driver.
I have produced studies that show that is not true. What do you have that supports your position.
Adam,
Since you only want to hear from climatologists, here is the link to an interview with Mike Hulme, founding Director of the Tyndall Centre for Climate Change Research.
http://www.theregister.co.uk/2009/05/06/mike_hulme_interview/
Steve,
Did you actually read that article? From the top of its second page:
"He stresses that he has little problem with the basic scientific understanding of climate change. Itâs just that, if progress is to be made in debates on how to respond to that knowledge, they need to be opened up to other disciplines, from the arts and humanities, for example - and to good old-fashioned politics and ideologies."
If so, what is your point?
Vernon -
The same thing holds here as holds in the other thread regarding the studies you reference. They all show that CO2 lags temperature in the historical record, but this is a fact that no one disputes.
What the studies do NOT show is that CO2 cannot act as a driver of temperature change.
Adam: No, they don't show that CO2 cannot act as a driver, but they eliminate it pretty obviously as the 'main' driver. That's pretty much all anybody has ever tried to point out.
Adam,
on the other thread I pointed out that less that 30 percent of warming was due to CO2, that warming peaked before CO2, and that CO2 does not explain the LIA or MWP.
Coby claims that CO2 is the main driver, the studies and the historical record prove that CO2 is not the main driver or even a strong driver compared to the "unknown" driver. Or as those of us that are not fixated on CO2, call it solar activity.
Please read what Coby's position is that your defending. It is not what you claim.
Vernon and Chris
So, it was not the main driver of increasing temperatures in the past, yet 30% of the warming can be attributed to increasing CO2 concentrations, and that for the observed temperature increases, CO2 was necessary.
So, then, how does this contradict modern global warming theory? I think that's the part of your argument that I'm not connecting to.
Adam,
What do you think is being discussed here? Coby's position is that CO2 was the main driver in the past and in the present. CO2 has never been a major driver.
CO2 was fairly consistant though the MWP or LIA but the temperatures changes anyway. There is some warming due to the GHG nature of CO2 but there is no evidence that CO2 is much more than a feedback to temperature change.
Coby,
You have stopped discussing this. Do you have any evidence to present that shows that CO2 is a major climate forcing agent? If you cannot produce any evidence for your position, will you be retracting this a few other of your talking points?
Vernon, a good place to start is here:
http://scienceblogs.com/illconsidered/2008/10/what_is_the_evidence_that…
Coby, the warming in the early part of the 20th century was attributed solar. The cooling was attributed to aerosols, even though there is no evidence of the make-up, quantity, or forcing of the aerosols. The IPCC report which you reference says that clouds, solar, aerosols, basically everything but GHGs are pretty much not understood.
With that as the basis of our current understanding you think that we should blindly accept models which do not actually model the MWP or LIA. To the point that the history was rewritten to show there was not a MWP or LIA.
Coby, read the studies! The current non-treering studies show that there was a MWP and LIA. The whole man-made global warming, end of civilization argument is falling apart.
Vernon -
I realize I'm futilely smashing my head against the wall here, but once more into the breach.
CO2 was fairly consistant though the MWP or LIA but the temperatures changes anyway.
Even assuming that these periods were global (and there's considerable reason to think they weren't), this is irrelevent. You're pretending here that anyone is arguing that CO2 is the only driver of global temperatures. I can't tell, though, if you're being disingenuous, willfully blind, or just aren't understanding what people are saying.
There is some warming due to the GHG nature of CO2 but there is no evidence that CO2 is much more than a feedback to temperature change.
If CO2 is a greenhouse gas, it will influence temperatures regardless of how it is introduced to the atmosphere. Your argument just doesn't make any sense. Whether coming out of the oceans and permafrost, or by burning fossil fuels, the effect is much the same.
Coby, the warming in the early part of the 20th century was attributed solar. The cooling was attributed to aerosols, even though there is no evidence of the make-up, quantity, or forcing of the aerosols.
Here's a graphic that shows the attribution of drivers over the past century. Higher aerosol content is generally attributed to increased post-war industrial activity.
http://en.wikipedia.org/wiki/File:Climate_Change_Attribution.png
With that as the basis of our current understanding you think that we should blindly accept models which do not actually model the MWP or LIA.
Meta-analysis of the models shows they can recreate the 20th century pretty well. This is a good reason to put some trust in the models.
http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/…
http://www.newscientist.com/data/images/ns/cms/dn11649/dn11649-1_688.jpg
We don't have as good information for what happened 1000 years ago, so we don't necessarily expect to be able to model it as well.
Coby, read the studies! The current non-treering studies show that there was a MWP and LIA. The whole man-made global warming, end of civilization argument is falling apart.
I'm not sure what studies you are referring to that refute global warming theory, but they certainly don't appear in peer-review publications. The existence (or lack thereof) of the MWP/LIA does nothing to refute global warming theory. Regarding your last sentence, I do wish I could share your positivity that global warming isn't occurring due to human influence. It would be nice, wouldn't it?
Wow,
I am really concerned here. Everything is moving in the wrong direction. Everything that's supposed be going up is going down! And everything that's supposed to be going down is going up! To quote a famous scientist, er, politician.
Global surface temperatures are going down.
Global sea temperatures are going down.
Polar sea ice extents are going up.
Arctic sea ice thickness is going up.
Antarctic ice mass is going up.
Sea levels are rising less than historical averages.
All the "fixed" data is found to favor AGW. And when the facts come out it doesn't.
The only thing going in the right direction is CO2.
What is one to believe? Well, I'll start by believing what I can see.
Hi Paul,
Global surface temperatures are going down.
False
Global sea temperatures are going down.
False
Polar sea ice extents are going up.
False
Arctic sea ice thickness is going up.
False
Antarctic ice mass is going up.
True
Sea levels are rising less than historical averages.
False
Hmm. Not such a great score.
Would you like to provide references for all your claims here Coby? And no i do not want them from your site or RC thanks. Lets try and keep the incestral aspect out of this.
Cheers
Coby,
Your wrong. CRU, RSS, UAH all show that since 1999 the global temperatures have been going down.
Argo buoys show that surface sea temperature have been going down and further there has been no deep water warming.
Arctic sea ice extent has been increasing for the last two years.
A recent survey has shown that Arctic sea ice is thicker than scientist had though, much more multi year ice.
Antarctic ice mass is increase, Antarctic sea ice is increasing.
Sea levels increases have slowed or stopped for the last few years.
Coby, if you want I will present the studies, but since your don't...
I notice that you have quit addressing my posts, conceding again?
With answers like Coby's above reflected against observed conditions . . .
Well, like I said, I'll believe what I can see.
Vernon -
Your wrong. CRU, RSS, UAH all show that since 1999 the global temperatures have been going down.
False, but in any case, it is irrelevant.
http://www.cdc.noaa.gov/csi/images/GRL2009_ClimateWarming.pdf
"We show that the climate over the 21st century can
and likely will produce periods of a decade or two where the globally averaged surface
air temperature shows no trend or even slight cooling in the presence of longer-term
warming."
Argo buoys show that surface sea temperature have been going down and further there has been no deep water warming.
Do you have a reference for this? Because, looking at the long-term trend, we see ocean heat content increasing.
http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
Arctic sea ice extent has been increasing for the last two years.
For reasons discussed elsewhere, this is a nonsensical argument. As stated before, you can show the same short-term gain many times over the past 30 years, all over a long-term decline. I don't get what's so hard to understand about this.
A recent survey has shown that Arctic sea ice is thicker than scientist had though, much more multi year ice.
Not sure where you're getting this from, but I'm not seeing any evidence of this. Without a source, it's impossible to know whether you're making your normal error of inferring long-term trends from a short-term increase.
http://www.sciencedaily.com/images/2009/04/090406132602-large.jpg
Antarctic ice mass is increase, Antarctic sea ice is increasing.
Can't argue with this one.
Sea levels increases have slowed or stopped for the last few years.
Again with the confusion about extrapolating long-term trends from short-term data.
http://www.pol.ac.uk/psmsl/author_archive/church_white/GRL_Church_White…
Paul in MI -
I hope you see long-term trends, and don't focus on short-term noise. This is a common mistake (as evidenced by Vernon and Crakar).
Adam,
Your right I typed 1999 when I meant to type 2001.
Year 01 02 03 04 05 06 07 08 Least squares trend
GISS .56 .67 .65 .59 .75 .64 .72 .55 +.0037
CRU .41 .46 .47 .48 .42 .41 .32 .36 -.0154
UAH .20 .31 .28 .20 .34 .26 .28 .05 -.0133
So yes, they show cooling (well except GISS and they change that to fast to be sure)
That is really good that we are warming with the temperature going down.
One study that used Argo data: Lyman et al (2006)
Arctic sea ice thickness: http://www.awi.de/en/news/press_releases/detail/item/pam_arcmip/?cHash=…
Adam,
Live by noise, die by noise.
But long term trends may change.
Vernon,
Just for fun, do your numbers again using 1999-2008 instead. Then one more time using 1998.
You will get very different results for each of your three exercises, which tells you your analysis is inappropriate for the question you are trying to answer. The inter-annual variability is up to .2oC. The trend is .015 per year. You can not use such a short data set.
I checked your AWI link. The only mention of results was this:
Their results show a strong decrease of ice thickness in the central Arctic which was sporadically surveyed from RV Polarstern. However, nothing is known about changes in other regions.
They also said this:
he extent of Arctic sea ice has declined stronger than predicted by climate models.
Coby,
Your like a moving target. Your position was
Got an even better one, do the trend for any lenght of time and do a 4th polynomial trend. It clearly shows that global temperatures have been cooling.
Coby, you keep dragging the converstation off topic and I keep letting you, but now lets get back on subject. Your position was CO2 is the main driver once warming starts. In previous posts you specifically say:
Vespacian -So you are saying that at first, the horse pulls the cart. Once they are rolling, the horse jumps on top of the cart and the cart pulls the horse. I get it.
Coby - yes, that is what I am saying. But your analogy is poor because the horse-cart scenario can't happen that way and it is contrived to make the concept sound ridiculous. Try to think of a situation where there is a real feedback effect, there are many. It is not so difficult to understand
I have presented studies that show that CO2 could have at most been responsible for no more than 30% of warming during the last glacial termination. Now you are twisting the discussion into something else other than the fact that CO2 was not and has never been shown to be a major climate driver.
You can keep changing the subject but the fact is that your position is not supported by the facts. So, without once again changing the subject to deflect the discussion, address the fact that your position is not support by historical evidence.
Vernon -
Is your claim that cause X being responsible for 1/3 of effect Y renders it insignificant? Maybe our standards differ, but 1/3 is pretty damn significant proportion (read: major).
Besides, the historical data is interesting, but doesn't really tell us a whole lot about what's going on today (other than to confirm that CO2 does have a strong influence on climate).
Also, why use a 4th order polynomial? I can come up with trends on a dataset to show lots of different things, but that doesn't necessarily mean they are good fits.
This is a very topical post, apparently. It's a nice explanation of curve-fitting data.
http://tamino.wordpress.com/2009/05/11/dangerous-curves/
Adam,
I did not say it was 1/3, I said that the studies show that it did not exceed 30%, could be less but the actual CO2 caused warming is unknown.
Finally, this discussion is on Coby's talking point that even though CO2 lags warming, once CO2 starts it takes over as the dominate climate forcing. The historical record shows that Coby is wrong.
This is the topic, and I am going to stay on topic for once.
Coby,
How many of these threads are you going quit answering on? How about some science that refutes what I have posted? Are you conceeding?
From ice-core records we can see a high correlation between GTG (greenhouse trace gas) concentrations and temperature variations over 420,000 years and through four glacial cycles.
In 1999 a paper was published showing that CO2 increased several centuries after the warming of the last three deglaciations. Something caused the Earth to warm and come out of the ice ages â it was not CO2 or GTGâs.
But why did CO2 go up later? Well one explanation that seems reasonable to me is the change in land ice coverage and the buildup of the terrestrial biosphere. As the ice sheets retreated grasses and trees moved in CO2 and methane built up, further increasing the temperatures due to the greenhouse effect. Then something caused the temperatures to fall and the build up of CO2 and other GTGâs were not enough to offset this. CO2 levels remained high as the temperatures plunged sending the Earth into another ice-age.
What was that something? The IPCC and coby have been at pains to tell us that the TSI of the sun varies only slightly â it couldnât possibly explain the changes in global temperatures. ITS NOT THE SUN STUPID!
To me its clear that CO2 was not the driver of the climate in the past. It was the sun â DIRECTLY and INDIRECTLY. But that is for another time.
The dominant climatic feature of the Earths climate in the last 2 million years have been the ice ages, interspersed with relatively brief warm periods of about 10,000 years. We are currently in an interglacial period. The longest on record. What we really need to fear is another ice age not warmer weather.
Svante Arrhenius was a genius. Maybe he was right - anthropogenic greenhouse gasses may stave off another ice-age for another few centuries.
I don't understand what the controversy is. Reading these comments I get the impression someone rescinded the Greenhouse effect. CO2 is a major Greenhouse gas and increasing it by 50% will have a strong effect on climate. That's just common sense, but it turns out some very sophisticated climatological models predict the same result. What a surprise. Who knew that burning in 100 years what it took nature 100 million years to fix would have an effect on the planet? (/sarcasm).
As for the ice-core record, primarily it shows a very strong correlation, over 300,000 years, between CO2 and temperature. One goes up, the other goes up. This shouldn't really surprise us, given the physics behind the Greenhouse effect: yet it seems a surprise to so many people posting on this thread!
Secondarily, the ice-core record MAY show that orbital effects precede CO2 effects in forcing historical climate. Is this a surprise to anyone? Is the Milancovich cycle a new thing?
On the other hand, the 800 year lag may reflect a lag in O18 absorption rates (versus CO2 absorption rates). Or not. Would knowing somehow invalidate the Greenhouse effect, or the climatological models (read: applied physics models) that indicate a CO2 forcing in our climate? Aye, there's the rub. The high historical correlation between CO2 and temperature helps validate the physics behind the Greenhouse effect. To believe that CO2 cannot cause heating based on the ice-core record, you ALSO have to believe the Greenhouse effect is bunk. And that's just a denial of basic radiation physics.
Again, the PRIMARY conclusion of the ice-core record is that temperature and CO2 move together. That is just a REAL strong correlation over such a long time period. Hence, common sense suggests that if CO2 goes up by 50%, temperature should also move up. And to claim, as some do, that CO2 is now going to move, BUT TEMPERATURE ISN'T, is a leap of faith that frankly ignores a 300,000 year old record of STRONG correlation. It could happen, but it asks for a one-time exception to a 300,000 year old rule.
The SECONDARY conclusion, is that temperature rise historically precedes CO2 rise. This was predicted by warming advocates, like James Hansen, almost 20 years ago, it is consistent with what we know about the Milankovich cycle, and is verified from the ice-core data. It just ISN'T TRUE NOW. Say what you will about the accuracy of CO2 and O18/O14 measurements in ancient ice bubbles, but we have a pretty good idea what is happening NOW. And CO2 is off the charts. Gore's illustration is this: Given the PRIMARY conclusion of the ice-core record, WHAT DO YOU THINK IS GOING TO HAPPEN to temperature?? And then put that together with what we know about the Greenhouse effect, and what the climatological models are predicting, and you have to be in a powerful mode of denial to expect the PRIMARY rule of the ice-core data is going to be broken after 300,000 years. For CO2 to now NOT show a correlation with temperature requires 3 things:
1) You have to break a 300,000 year old winning streak.
2) You have to rescind the Greenhouse effect.
3) You have to invalidate the applied-physics models of the climatologists.
Sorry. But that's just too much 'faith' to ask of ordinary people. If deniers could successfully break just ONE of these rules, it'd be a start, but I won't hold my breath.
ubrew: I'm not very impressed with your 'refutation.' Your first point seems to be that CO2 is a 'major' greenhouse gas; it is certainly not. Even the highest estimates put CO2 as responsible for less than a fourth of the total greenhouse effect. Anthropogenic CO2 is, at most, less than seven percent of the total greenhouse effect. Sorry, CO2 is not 'major.' I'm also not sure what you're talking about when you say 'increase by 50%.' We haven't come close to that high a change.
You do a lot of talking about CO2 lagging temperature, and indeed it should not surprise us, given the physics of a gas liquid interface at changing temperature. Temperature goes up, the ability of the liquid to dissolve a gas goes down: Temperature goes up, CO2 goes up afterward. Temperature goes down, CO2 goes down later. Exactly as expected, no need to resort to the greenhouse effect. Please stop trying to obscure this point.
The other favorite argument that seems to be brought up pretty much every time is this: "yes yes, we took high school chemistry too. But what you fail to realize is that the magnitude of the temperature increases CANNOT BE EXPLAINED WITHOUT THE GREENHOUSE EFFECT OF CO2." Some of you are nodding your heads, thinking this a very reasonable, scientific thing to say. It is not. That statement amounts to: "we couldn't think of anything else to explain it." Make zero mistake. That is what you are being told. That is not scientific. Let's illustrate an example:
Mr. A. is found dead in his house. Of course the investigation begins to look for his murderer. Mr. A. is known to associate only with close friends Mr. B, Mr. C, and Mr. D. Mr B and Mr C have good verifiable alibis, they were not at the house when the murder took place. Mr D has no such alibi. Therefore he is guilty! Hopefully we can all see the failure of logic (and the legal system) in the case of Mr A and Mr D. The jury and judge couldn't think of anybody else who could have done it, so it must be Mr D. What are they leaving out? Perhaps there are as yet unknown persons involved. Perhaps it was a suicide. Perhaps it was simply an accident. Narrowing your viewpoint based on what you think you 'know' about a situation can lead to a very drastic mis characterization of that situation.
For many years, it was 'known' that since light is a wave, it must have a medium to propagate through. There was no other explanation. The medium was deemed the aether. The aether was searched for tirelessly for many years before finally being shown to not exist. Light is not a wave in the sense that the best physicists of the day assumed.
Be very very careful when you hear 'there is no other explanation.' It is not a scientific statement. It can of course lead to new scientific discoveries (like the fact that the aether does not exist, or that the neutrino in fact does) but in and of itself it is not a valid scientific refutation. The temperature increase shown in the ice cores could have come from factors we know about but take improper account of, unknown factors, etc. Just because nobody can think of a better answer is not a reason to accept it.
So I hope that can be viewed as a fair and scientific breaking of 'rule number one.'
Rule number two is fine how it is.
Rule number three is laughable. The models have been invalidated over and over again. And please do not try to lend them credibility by calling them 'applied physics models.' Any model for physical phenomenon had better be an applied physics model. It's nothing special, and it implies no measure of correctness. Currently, the models are nothing but extensive curve fitting exercises. 'Hindcasting' is simply curve fitting. And it is amazingly easy to do so when one is working with so many variables, and so many unknowns. Feel free to prattle on about how amazingly complex the models are (I know this), or how far beyond my knowledge they go (I'm aware), or how they are made by much much smarter people than me (10-4). It doesn't change the fact that the models you cling to so dearly have gotten more wrong with each passing year, when they should be getting better. You can take Gavin's route and choose to ignore data to make your hypothesis work, but that's called cheating. Or perhaps... Cherry picking.
I know, the answer is 'weather noise.' Perhaps. But it becomes less and less likely every single day. It is disappointing to see so many people choosing to believe that their pet theory is hiding behind noise right now, rather than trying to reformulate it to better reflect current data.
So you can stop holding your breath now.
ubrew12,
I almost hate to break this to you but there is a concept called causality. Basically, this means that while there is a correlation between temperature and CO2, CO2 cannot be the cause of the temperature since it happens after the temperature rises. Coby's point is that once CO2 starts rising, it becomes the principle climate driver. There is no evidence of this. What is shown is that the temperature peaks before the CO2, which would not happen if CO2 were a strong driver. History also shows that the temperature drops before the CO2 starts going down.
Vernon: the concept of 'causality' is called the Greenhouse effect. It relies on no cherry-picked, curve-fitted data. Its accepted Physics for 200 years, 160 of which were before the 'Global Warming' controversy. It is reproducible in the Laboratory.
Now, we have a 300,000 year record of CO2 and temperature rising and falling in virtual LOCKSTEP. If you were just some yokel off the streets, and you saw CO2 was going through the roof, and you knew of this 300,000 year old relationship, WHAT WOULD BE YOUR CONCLUSION?? Your conclusion, because you know 'better', is that there will BE no relationship THIS time. For that to be your conclusion, you have to:
1. Say that a 300,000 year old trend will break itself just for us.
2. Say that the physical causality ESTABLISHED by the accepted physics of the Greenhouse effect has no bearing here, but that the chemistry of CO2 solution in H2O does.
3. Say that the codified science represented by more than 10 climatological models, representing as much of the relevant physics/chemistry as can be incorporated by current science, are in error by oversight or, worse, collusion.
4. Say that the dramatic rise in global temperature since 1880 is 'in the noise', while the failure of temperatures to rise since 1998 is somehow significant!
Chris: ANY prediction about the future comes from a model. I get the fact that the most sophisticated computer model at Lawrence Livermore Labs can't possible hold as many variables as the model in your head, but don't pretend that you aren't operating from a model. And don't pretend that you aren't extrapolating the past where necessary to make your predictions (curve-fitting). Indeed, how good ARE you at integrating the first and second laws of thermodynamics for atmosphere and ocean, and adding Newtons second law where necessary? In fact, your claim that 'nothing is going to change' may be ENTIRELY based on extrapolation of the past. The problem with the model in your head is WE WILL NEVER KNOW, will we?? While you feel free to lob anarchic bombs at the constructions of other thinkers who've taken the time and effort to apply Newton and Gibbs to their physical systems, you're probably using those SAME relationships to justify your own work. Just as an example of your fallacy, you say, 'CO2 [is] responsible for less than a fourth of the total greenhouse effect'. OK. Is that a lot? Is it a little? Based on what you said, if CO2 levels changed by 1/10th of a percent, what would happen? The fact is, your statement alone doesn't TELL US ANYTHING. Now, you put your statement into a climatological model, with what we know of radiation physics and NOW we can say something about it. And what the models say is: a 50% rise is SIGNIFICANT. But the model in your head says, 'No, it ain't'. Who are we to believe? Tough question...
Maybe its NOT Anthropogenic CO2. Maybe its something 'else'. Frankly, Chris, what you're asking me to do is to enter a room while you say, 'Ignoring the ELEPHANT in the room, WHY is this room so stuffy?'
Good luck finding your mysterious 'Mister E'. Sometimes, it IS the aether.
The word 'driver' is probably misleading.
Regarding ice ages (particularly glacial terminations), CO2 is an amplifier of a warming initiated by orbital variations. All the post-80s studies I've read concur on this point, as well as acknowledging that insolation changes from orbital variations are too weak to have a strong effect on temperatures, and that greenhouse gases have a greater effect.
1990 - http://www.atmos.washington.edu/2003Q4/211/articles_required/Lorius90_i…
1999 - http://www.daycreek.com/dc/images/1999.pdf
2003 - http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf
2007 - http://pubs.giss.nasa.gov/docs/2007/2007_Hansen_etal_2.pdf
The above studies are a pretty good reflection of progress on the science from 1990. I'll summarize the pertinent points in chronological order, note-style.
1990 - "the total insolation received by Earth has varied by <0.7 Wm2 over the past 160 kyr"
Global increase during deglaciation reckoned to be 4C - 5C
Greenhouse gases reckoned to account for about 50% of the warming (40% - 65%), followed in magnitude of forcing by albedo change. Orbital forcing is a distant third.
Notes that similar warming amplitude over both hemispheres cannot easily be explained except by a total atmospheric warming. I.e. orbital forcing and ice sheet changes could not account for both hemispheres warming. Atmospheric warming plays a significant, possibly dominant role.
CO2 alone reckoned to account for 35%+ of global warming.
This may mean that CO2 alone is the dominant factor in global warming at glacial termination, as ice sheet decrease is amplified by atmospheric warming.
1999 - Greenhouse gases contribute to about half of the warming (2 - 3C) at glacial termination.
CO2 increases lagged by about 600 +/-400 yrs.
Sequence of effects at glacial termination: orbital forcing, then GHG, then deglaciation enhancement.
2003 - corroborates 1999 and posits new lag of 800 +/-200 yrs.
2007 - synthesis of past and recent studies. Deglaciation warming calculated at 3 - 4C tropics, 10C at poles, and 5C global.
Global mean forcing due to orbital variations is estimated at 0.25 wm2.
ubrew12,
I guess causality is beyond you. You do know that causality is "cause and effect?" That you have to have the cause before the effect or it is not the cause of the effect. Feel free to explain how CO2 cause warming 200-2500 years before the CO2 started rising. Oh and while your at it, please explain how temperature dropped before CO2 started going down.
Everyone agrees that there will be some warming with CO2. That is not the issue, the issue is what are the feedbacks to that warming. The "warmest" such as yourself and Coby believe that there is positive feed backs that will make the warming greater than what the CO2 alone would produce. That is a theory which has not been proven. That is what this discussion is largely about. That is what there is no proof of. Of if you want to make it simpler, please point to a study that can actually identify the warming due to CO2. This is a trick question because there is not one. Why because the models do not work.
Let talk models where you are bluntly stupid. The only thing that is scientific in the models is the fluid flow dynamics. Just about everything else is not based on "science" because we know that "science" per the IPCC reports flatly says that we do not know the science yet. Things like the sun, clouds, aerosols, etc. are currently unaccounted for in the models. Oh and the biggie for the models being wrong, please show how the models address long term temperature dropping while CO2 is high. No, I am not talking about the current 10+ years of cooling, but what is shown in the ice record, the start of the glaciation.
You do not seem to have a clue about the discussion. Coby's position, and the position of this talking point is that once CO2 starts increasing it becomes the primary driver. That is Coby's position and his words. The fact that CO2 is a weak GHG is not being questioned. The fact that basic chemistry takes place and after the oceans warm, they retain less CO2. This cause the atmospheric CO2 to increase. There in lies the rub. If Coby is right, then the temperature would not peak until after the CO2 peaked, additionally, once CO2 peaked, the temperature would not go down, yet it does.
Vernon, why do you keep repeating the same nonsense over and over again on every blog that still allows you to post?
You keep being told that you don't understand the difference between a forcing and a feed back.
Go and read about Milankovitch cycles since they are important in starting warming after Ice Ages.
You get an F once again. How do you manage to keep your grades at such a ridiculously low level for so long? Most people get embarrassed by being wrong all the time that they try to improve, you don't seem to be capable of any improvement.
In a post sitting on the waiting list (hopefully to be admitted), I got a reference wrong.
'Cuffey & Vimeux 2002' should read Cuffey & Vimeux 2001.
I mixed it up with Vimeux et al 2002, for which Cuffey was also a co-author, and which is also apposite to the point being made.
To ubrew12,
Below is a link that shows Co2 lags temp,
http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/
This site is obviously where you and Coby do a lot of reading as you two are repeating this verbatim.
I have three questions which you should be able to answer if you have any idea of what you are talking about.
First, what caused the initial warming? And no i do not want your opinion i want verifiable facts. Without this then you have no credibility when it comes to "but Co2 took over the warming" story line.
Second, the story you tell says after (something) started the warming the oceans warmed releasing CO2 which then warmed the planet even more, if so the oceans would also release water vapour which as we all know is a much more powerful GHG so please explain, A, why is water vapour not mentioned in any of your theories? and B, How much of the warming can be attributed to the release of said water vapour?
Also where is the negative feedback? According to your theory (something) began the warming releasing CO2 which then continued the warming, which in turn would release more CO2, which in turn would continue the warming, which in turn would release more CO2, which in turn........well you get the picture. So if there was no negative feedback then we would see a continual rise in temp and CO2 since the last ice age.
Of course we all know this is not the case, so please explain how this negative feedback works and where is it today, why do we not have a negative feed back in the 21st century.
The 'negative feedback' is a reversal of the initial forcing, insolation changes due to orbital variation.
Past the peak of the ~100 kyr Milankovitch cycle, the Earth's obliquity declines and the focus of insolation moves back to the lower latitudes. This causes cooler temps in the Arctic which causes ice sheets to recover, increasing albedo and lowering temperatures. The cyclical nature of ice ages is triggered by orbital changes, which are then followed (and amplified) by changes in the atmosphere and environment. So, while the cycle is determined by orbital variations, the amplitude of temperature changes is largely a result of Earth in-system environmental changes.
Coby, is it possible for you to post my longer effort (if you do) last in the thread?
Thanks for the response Barry,
However here is a list of theories, maybe you could take your pick from these, you will note that the Mcycle theory is rejected due to the fact that the changes in insolation are too small to drive the ice age cycle.
http://www.sentex.net/~tcc/iceage.html
Here is a study that puts the "CO2 made it warmer" theory to bed.
http://www.eurekalert.org/pub_releases/2007-09/uosc-cdd092507.php
Here is an abstract that once again pours cold water on the M cycle theory
http://muller.lbl.gov/pages/iceagebook/IceAgeTheories.html
In regards to the negative feedback, i dont follow what you are saying. Are you saying that solar insolation increased therefore CO2 increased then solar insolation decreased to produce a negative feedback?
So does water vapour play a role or is it to be ignored?
barry,
that would be fine except that both glacial termination started in the Antarctic before the MC reduced the isolation changes in the Northern Hemisphere. So, for what your saying to be true, reducing the TSI in the Antarctic leads to warming. I hope you see the problem with that argument.
That is the paradox associated with the MC theory.
A good question, Vernon. As I understand it, the early warming in the Northern Hemisphere raises sea levels globally, which affects ice shelves in the Antarctic, decreasing albedo. Ocean circulation transports heat from North to South. Warmer air may also be transported to the southern oceans (coeval with increased humidity). Methane release apears to happen earlier than CO2 (as ice sheets decline in the NH) The early warming is magnified later by GHG accumulation.
However, it's been a while since I read on these details and I didn't focus on them as much as the amplitude of various forcings and the phase lag. I have this study to hand.
http://earthsciences.ucr.edu/gcec_pages/docs/Bender%20et%20al%201994-Na…
Quartenary glaciation changes are rich with hypothesised feedbacks of all types and in both directions. I'm fascinated by this area of climate studies, as well as atmospheric spectroscopy.
I'll try to read more on your inquiry as time permits. In the meantime, if you're genuinely curious, I've found that searching in google scholar and checking all versions, copy and pasting some of the abstract to a search engine, and especially clicking 'web results' often yields a free online version of potentially pertinent research papers (if you don't know this already). I'll check back here to see if you've lit upon something that furthers both our understanding.
Vernon (and to a lesser extent Crakar) -
Have you completely ignored everything that has been said previously in this discussion? You keep repeating the same inanities over and over again, specifically:
Feel free to explain how CO2 cause warming 200-2500 years before the CO2 started rising. Oh and while your at it, please explain how temperature dropped before CO2 started going down.
Once again: CO2 is not the initial driver, but it contributes as a major factor in the overall warming period. This is called a feedback effect. Estimates put the total contribution of CO2 to the warming during these periods at around one-third of the total. As barry says, the temperature drops when the initial forcing reverses.
Everyone agrees that there will be some warming with CO2. That is not the issue, the issue is what are the feedbacks to that warming.
Actually, that is the issue. We know CO2 contributes to warming (you yourself admit this), we know that CO2 is released into the atmosphere as the earth warms, and we also know that this is not the only influence on global temperatures. This CO2/temperature relationship is a positive feedback (one of the things we are concerned about). You yourself admit all these parts, yet you absolutely refuse to make the connection, for whatever reason.
There in lies the rub. If Coby is right, then the temperature would not peak until after the CO2 peaked, additionally, once CO2 peaked, the temperature would not go down, yet it does.
Again, you are wrong. You keep assuming that CO2 is the only factor that influences temperature, while trying to convince everyone that CO2 doesn't have a strong effect. How you can keep this inconsistency in your mind is completely baffling to me.
Adam,
try as you might, you cannot change the discussion at this point. I will quote Coby yet again:
Comment 20 by Vespacian - So you are saying that at first, the horse pulls the cart. Once they are rolling, the horse jumps on top of the cart and the cart pulls the horse. I get it.
Comment 21 by Coby - Vespacian - yes, that is what I am saying. But your analogy is poor because the horse-cart scenario can't happen that way and it is contrived to make the concept sound ridiculous. Try to think of a situation where there is a real feedback effect, there are many. It is not so difficult to understand.
Adam, Coby's position is that once CO2 gets started, it takes over. This is what is being discussed. The facts do not support this position. While there is some warming due to CO2, it is not the principle climate forcing.
There is no proof, either in the past or in the present that shows that warming due to CO2 has positive feed backs. Please do not point to the models.
Vernon, once again you show that you have zero ability to understand some thing as complicated as climate science. You would be much better spending your time reading some elementary (and I do mean elementary as in 6 to 11 year olds) science.
You have zero understanding of the difference between a forcing and a feedback. Without that knowledge, everything you say is just rubbish. During the interglacials CO2 was a feed back to the increased solar insolation induced by Milankovitch cycles. Right now CO2 is driving since it is upsetting the natural equilibrium.
Are you as stupid as you appear or do you have ulterior motives for posting this rubbish? You are as grating on the mind as a sticky record. Give it up.
Vernon -
Once again, I'll reiterate. I'm not arguing against Coby's position, I'm arguing against YOUR position which is that CO2 CANNOT drive temperatures because of the observed lag. If I am misrepresenting your position, please clarify what exactly it is you are trying to argue.
Adam,
I know your not arguing against Coby's position, your arguing for it. Coby's position is that because there is correlation between temperature and CO2, there must be causality, even with the CO2 lagging temperature. This is a very basic logical flaw. Further, Coby says that CO2 takes over as climate driver.
My position is that CO2 is a GHG. That each doubling in lab experiments shows we should expect an ~1.2C increase. So far, the real world shows that the current increase in CO2 could have produced ~0.7C, I say could of because not all the climate drivers are understood. This leads to two possible cases:
The first case is that all current warming is due to CO2. If we stipulate that all the warming is due to CO2, then the real world shows that there are no positive feedbacks. That the only increase that can be shown is that due to the CO2 and there are no feed backs.
The second case, and the more likely one, is that since we do not know all the climate forcings, then the actual temperature impact of CO2 is less than what the lab experiments would suggest.
In either case, there is no real world evidence of CO2 having a positive feedback that causes more warming than can be attributed to the CO2 directly. We know the models are not based on scientific principles, since it is hard to program scientific principles when at this point we do not know what they are. Hunt et al (2005) found that the models could not reproduce either the MWP or the LIA as part of the normal climate. The models are parametrized best fit with the parameters being guesses to make the trend match the calibration period.
Further, the models call for polar amplification, which there is none, and a upper tropospheric hot spot at the equator, which there is none.
Basically, I believe that CO2 should cause some warming but there is no evidence that it will cause the excessive warming predicted by the models.
Once again Vernon shows that he hasn't a clue about simple physical chemistry (ClausiusâClapeyron relationship) and climate science.
I can't believe that anyone can be so arrogant as to claim over and over again "facts" that he has been told repeatedly are wrong. He knows nothing about the science but "knows" that all the climate scientists are wrong. Such stupidity and arrogance.
To Ian, Adam Et al,
Before we get carried away with the name calling.
lets take a closer look at your theory shall we.
First of all you claim the MC causes an ice age, ok lets accept this fact for now, although from what i have read this is not a universally accepted theory.
So then over a period of time something happens and the Earths temps begin to rise and 800 years later the CO2 levels begin to rise.
At this point the CO2 takes over control of the climate and becomes the major climate driver. Thus proving that CO2 is the major climate driver today. Is that about right?
Ok so now lets pick holes in your theory.
First question, what caused the temp rise from time 0 to 800 years?
If CO2 took control of the climate back then with no negative feedbacks what stopped the CO2 and therefore temps from rising uninhibited to very high levels?
Can you answer these questions? because if you cant then your CO2/ice age theory is invalid.
Here is a link that shows the oceans warmed from the ground up, in other words the deep ocean warmed first and this heat the rose up to the surface.
w.w.w.wnd.com/news/article.asp?ARTICLE_ID=57895
Now if your theory is true then the surface would warm first or from the top down correct?
So here is another theory, the oceans warmed releasing water vapour (oops theres that word again)WV of course being the most powerful GHG by a long way then began to drive up the temps and after 800 years the CO2 levels began to rise as well.
Now this is the point were you lot believe CO2 takes over, but please explain how CO2 can overpower the most powerful GHG.
Here is a good description of the temp v CO2 over the previous ice ages.
The author raises some good points about the role of CO2 and clearly shows CO2 lags Temp, it is clear to see that as the temps rise the CO2 follows and at no point does CO2 take the lead. It also clearly shows that once the Earth begins the decent into an ice age that CO2 levels get left behind and drop at an even slower rate.
An interesting point to note is that the same levels of CO2 during the temp rise and the temp fall produce a different temp. Which of course suggests that CO2 play only a minor role in controlling the Earths temp.
httpwattsupwiththat.com/2009/01/30/co2-temperatures-and-ice-ages/
crakar,
The first link
http://www.sentex.net/~tcc/iceage.html
discusses the early hypotheses on ice ages from 1875 to 1972, before deep ice cores were drilled and well before more precise dating techniques were extant. I'm not sure what relevance, apart from an academic historical point of view, this has on the current state of the science post-Vostok in the 80s. Go a little further back in time and we might argue that the flat-earth theory has legs. :-)
The second link
http://www.eurekalert.org/pub_releases/2007-09/uosc-cdd092507.php
is largely about the phasing of ice ages and makes small mention of greenhouse amplification. You said:
Here is a study that puts the "CO2 made it warmer" theory to bed.
I don't know how you can come to that conclusion after reading the article.
which we already agree on. The point has been made repeatedly by others upthread and again a few posts above. Stott apears to be aware of the potential to misunderstand the impact of his study.
The author also says of Stott's study:
which is in agreement with the thrust of the top post and many that have followed. There is no way that a careful reading of that article could result in the proposition that it 'puts "CO2 made it warmer" theory to bed.' And surely you're not suggesting that a single study wraps up the science on anything?
I've done some reading following Vernon's query on correlated temperature changes at both hemispheres and found elsewhere the contention (Stott's) that the Southern Hemispheric insolation changes may lead the Northern. As a result, I attach less confidence to the reply I made to Vernon.
The third link
http://muller.lbl.gov/pages/iceagebook/IceAgeTheories.html
is to Richard A Muller's book on climate. Most of his work is in spectral analysis of cosmic rays and events, but he has written some papers on ice ages. His contribution to the theory of ice ages is focussed on the triggers for glaciation changes. He has corroborated current conclusions on the dominance of obliquity and precession over eccentricity as the pacemaker of ice ages, acknowledges greenhouse gas amplification, and has attempted to link cosmic ray fluctuations with the onset and terminations of ice ages. The latter effort has met with little success and is a real outlier (his work on this is rarely cited). In any case, none of that adds anything new to this discussion of the role of of GHGs in glacial changes. We're all agreed that GHGs lag glacial terminations. What seems to be in contention is whether, or how much, GHG accumulation contributes to the overall warming until deglaciation. As there doesn't seem to be any substantiation to rebut the mainstream position - that GHGs contribute to a significant amount of the warming (about 50%), I'm no longer sure what is being argued.
You asked:
Are you saying that solar insolation increased therefore CO2 increased then solar insolation decreased to produce a negative feedback?
More or less, but I wouldn't put it quite like that. I'd go with the mainstream language - orbital variations are the pacemaker of the ice ages. The initial forcing reverses as the planet wobbles to a new inclination and the system responds to achieve equilibrium. In-system environmental changes are responsible for the lion's share of the global temperature changes, with GHGs seemingly the dominant factor. Water vapour would certainly play a significant role as a feedback mechanism.
I should point out that I'm no scientist, only an interested reader, and the best I can do is understand the weight of current understanding and reflect it as accurately as possible. I'm not trying to persuade anyone of anything, just trying to frame the state of the science, which is difficult enough, let alone trying to argue it is wrong. Having said that, Coby has posted my longer post upthread, for anyone who cares to read it.
Vernon wrote:
there is a concept called causality. Basically, this means that while there is a correlation between temperature and CO2, CO2 cannot be the cause of the temperature since it happens after the temperature rises.
Let me deal with the causality concept with the guitar/amplifier analogy.
Which one 'causes' the sudden howl from feedback?
Take away the guitar, no feedback. Take away the amplifier, No feedback. What causes the rise in audial volume? Both, acting on each other, whether the amplifier is turned up, or the guitar is brought nearer the amp. A change in the status of either may cause a feedback.
To the point, in past glacial terminations temperature rises cause GHG accumulation. GHG accumulation causes FURTHER temperature rises. This is a feedback system, which is triggered by an initial heating. The process reverses when the initial trigger (orbital variation) reverses. There are many feedbacks at play that influence timing and amplitude.
One fallacy here is to assume a single cause for everything. That's not how the real world works. We may point to a high-stress event that caused a woman to have a heart attack, but there's good reason to suppose her smoking and obesity contributed to her death, when healthier people by her survived the event.
To the best of our knowledge, GHG accumulation did not lead glacial terminations, but they contributed, significantly to the overall warming for the duration. I don't see why that sequence of causality is hard to understand, whether or not one accepts it.
And to repeat, the phasing of ice ages has no impact on the theory of AGW, which is a property of physics. Ice age responses are used in the science literature to calibrate climate sensitivity, not to corroborate industrial age greenhouse theory. It is largely because lay critics of mainstream AGW theory attempt to rebut it by referencing ice age dynamics that this debate occurs at all (in the semi-popular blog literature).
Crakar
At this point the CO2 takes over control of the climate and becomes the major climate driver. Thus proving that CO2 is the major climate driver today. Is that about right?
No. It supports the conclusion that increasing temperatures cause increasing CO2 concentrations, which cause increase temperatures (positive feedback, as barry explains).
barry,
Your example of positive feed back, while in agreement with the models, is not in agreement with facts. If warming from CO2 has a positive feedback as you suggest and describe than the climate system would unstable and always move to an extreme state. That is what the feed back loop in your example does. That is what all positive feed back systems do. The fact that the climate is stable is evidence that the overall feed back for any climate forcing is negative.
You are trying to change Cobyâs position which is what is being discussed. Coby holds that once warming starts and CO2 starts to increase, CO2 becomes the most significant climate forcing. If you read the discussion you would see that I am not claiming that CO2 does not cause any warming, only that it is not the most powerful climate driver at work.
There is no evidence that CO2 doubling will cause anymore warming than the 1.2C lab experiments show. There is no evidence in the present that increased CO2 will result in more warming than the 1.2C for doubling.
That models show more warming is not science or fact. I will repeat, we know the models are not based on scientific principles, since it is hard to program scientific principles when at this point we do not know what they are. The models are parameterized to best fit with recent climate. The parameters are nothing more than best guesses to make the model match the calibration period. Hunt et al (2005) found that the models could not reproduce either the MWP or the LIA as part of the normal climate.
You say that AGW is not disputed by the facts but that is not quite true. The facts are that one of the principle proofs of AGW CO2 warming was that the ice record showed that CO2 and warming were synchronized. Unhappily for the AGW camp, improved techniques soon showed that CO2 lagged warming, but that was ok because the new theory was that once the weak MC started the warming, CO2 took over. That is the position that Coby also supports. The problem is that CO2 peaks after the warming peaks. If CO2 were really adding to the warming then the temperature should peak after the CO2 does, but it does not.
Just to add to the fun, the proof of current warming being exceptional and due to CO2 is also falling apart. See:
Christiansen et al (2009)
http://web.dmi.dk/solar-terrestrial/staff/boc/reconstr_reprint.pdf
The underestimation of the amplitude of the low frequency variability demonstrated for all of the seven methods discourage the use of reconstructions to estimate the rareness of the recent warming. That this underestimation is found for all the reconstruction methods is rather depressing and strongly suggests that this point should be investigated further before any real improvements in the reconstruction methods can be made.
von Storch (2004)The centennial variability of the NH temperature is underestimated by the regression-based methods applied here [Mann et al], suggesting that past variations may have been at least a factor of two larger than indicated by empirical reconstructions. Frank et al (2005) The ring-width-based reconstruction substantially underestimates temperatures during the most of the overlap period with early instrumental data, with substantially lower values during the late 1700s and maximal divergence during the temperature minima around 1815.
D'Arrigo et al (2007)on divergence. The causes, however, are not well understood and are difficult to test due to the existence of a number of covarying environmental factors that may potentially impact recent tree growth. These possible causes include temperature-induced drought stress, nonlinear thresholds or time-dependent responses to recent warming, delayed snowmelt and related changes in seasonality, and differential growth/climate relationships inferred for maximum, minimum and mean temperatures.
Datsenko et al (2008) It is found that the Mann et al. reconstruction drastically underestimates low-frequency temperature variations, whereas the Moberg et al. reconstruction reproduces them much better, although with a certain underestimation rather than overestimation, as Mann et al. have recently argued.
Von Storch et al (2009)
The methods are Composite plus Scaling, the inverse regression method of Mann et al. (Nature 392:779â787, 1998) and a direct principal-components regression method. ⦠All three methods underestimate the simulated variations of the Northern Hemisphere temperature, but the Composite plus Scaling method clearly displays a better performance and is robust against the different noise models and network size.
Riedwyl et al (2008)
This paper presents a comparison of principal component (PC) regression and regularized expectation maximization (RegEM) to reconstruct European summer and winter surface air temperature over the past millennium. ⦠For the specific predictor network given in this paper, both techniques underestimate the target temperature variations to an increasing extent as more noise is added to the signal, albeit RegEM less than with PC regression.
So, there is no proof that CO2 warming has any positive feed backs. The models are not based on scientific principles but rather are parameterized and fitted to the calibration period. There is no proof that current warming is exceptional. There has been no warming this decade. The whole AGW theory is falling apart, could be why they are not pushing to change the name to climate change.
That's too much digression for me, Vernon. It seems you're more interested in arguing against the theory of AGW than acquainting yourself with the weight of scientifc opinion on the contribution of various factors on glacial transitions. One can find outlying papers to 'disprove' any theory, but unless that is balanced with a grounding in the mainstream view, the practise is opportunistic rather than objectively inquisitive, isn't it?
Your points are interesting of themselves, but none of them approach a falsification of the generally accepted principles of ice age dynamics pertinent to the thrust of the argument heading this thread - that orbital forcings, while the trigger of glacial changes (positive and negative), are too weak to account for the amplitude of global temperature, and that GHGs account for the lion's share of the warming. I've cited a raft of papers that are indicative of the weight of opinion. Here's another looking at the contribution of orbital variation to global warming at glacial terminations - around 10% (maximum of 20%, minimum of < 1%).
http://ocean.mit.edu/~cwunsch/papersonline/milankovitchqsr2004.pdf
If you wish to posit that GHGs cannot have acounted for much of the warming during interglacials, then perhaps you have some credible (recent) papers that explore that, specific, idea.
You write:
You say that AGW is not disputed by the facts but that is not quite true. The facts are that one of the principle proofs of AGW CO2 warming was that the ice record showed that CO2 and warming were synchronized.
That is simply not true. As I've said numerous times above, ice age dynamics studies were never cited as proof of industrial age global warming, although some studies make brief mention of the possible consequences. The reason it seems so is that the recent semi-popular debate has included the phase-lag discussion, but this corner of the conversation was initiated by critics, not proponents.
Unhappily for the AGW camp, improved techniques soon showed that CO2 lagged warming, but that was ok because the new theory was that once the weak MC started the warming, CO2 took over.
As the lag was first hypothesised before the first IPCC report, and formally submitted at least as far back as 1990 (the year of the first IPCC report), your history seems a little odd, and, I would guess, quite fictional. Once again, the theory never depended on ice age dynamics. Rather, the theory was built on spectral analysis, revivified in the 50s when the US air force discovered atmospheric layering, and from observations of atmospheric CO2 increase - well before GHG dynamics in ice ages got much traction in the literature. You have this wrong.
It might interest you that some of the earliest papers on lag was co-authored by James Hansen, in 1990.
http://www.atmos.washington.edu/2003Q4/211/articles_required/Lorius90_i…
A post of mine with some of those studies reflecting the progress of understanding was admitted by Coby and appeared upthread. Peruse it for corroboration if you wish. Some of your points just above are taken up there.
http://scienceblogs.com/illconsidered/2006/02/co2-lags-not-leads.php#co…
As to your other points, I'm not really interested in persuading anyone that AGW theory is robust and am content for you to maintain your opinion on that. Perhaps we will discuss other issues in the appropriate venues.
Vernon -
If warming from CO2 has a positive feedback as you suggest and describe than the climate system would unstable and always move to an extreme state. That is what the feed back loop in your example does. That is what all positive feed back systems do.
Once again, you fail to understand what a feedback is. A positive feedback is not inherently unstable, as long as there are multiple inputs (as there are in the real world). In mathematical models, sure, you can have a system that explodes to infinity, but in the real-world, this doesn't happen.
Take the case of the inverted pendulum: Sure, a perturbation will cause it to fall, but it's fall will be limited. It won't explode, even though a model can be constructed to show this explosion. (And before you jump in with any predictable comments about how this shows climate models are invalid, you can also construct a model that doesn't show this)
The fact that the climate is stable is evidence that the overall feed back for any climate forcing is negative.
All real systems are stable (so to speak). That doesn't mean they cannot have components that act as a positive feedback. I don't understand why this is so hard for you to grasp.
barry's example is actually a perfect illustration of this. His amp/guitar system will emit the positive feedback screech, but it won't explode to infinity because the speaker will break well before this happens. This is an inherent negative feedback to the system. This also, however, does not mean that there are no positive feedbacks present in the system.
So, there is no proof that CO2 warming has any positive feed backs.
You have already acknowledged that CO2 is a positive feedback!!!!! Comment 101: Basically, I believe that CO2 should cause some warming...
If CO2 increases because of a temperature increase, and that CO2 "should cause some warming" that is by definition a positive feedback. You can certainly argue about the extent of the warming that will happen, but to deny that there's a positive feedback is lunacy.
Adam,
In this your flatly wrong
"barry's example is actually a perfect illustration of this. His amp/guitar system will emit the positive feedback screech, but it won't explode to infinity because the speaker will break well before this happens."
I never said it would explode to infinity, I said that a system with over all positive feedback will always move to an extreme state. That is what that example shows. No one said explode to infinity, that is your phase not mine.
You are playing word games and being dense, I suspect, on purpose. If doubling CO2 causes more than 1.2C of temperature increase then the climate feedback is positive, if doubling CO2 causes less than 1.2C of temperature increases than the climate feedback is negative. Please point to some empirical study that shows with real world measurements that increased CO2 has lead to more warming than can be attributed to the CO2 alone. The answer is there is not one. There is theory, there is speculation, but there are no actual facts and measurements.
Vernon said: "You are playing word games and being dense, I suspect, on purpose". Vernon you are the one playing games and being arrogant and stupid. Anyone who wants to see how Vernon plays his game has only to visit the thread over at Deltoid (http://scienceblogs.com/deltoid/2009/04/open_thread_25.php) where he repeats his nonsense ad nauseum for approximately 200 posts. It is time that he is stopped since her will go on for ever.
He is clearly suffering from some sort of delusional psychosis.
I have never seen such a listing of completely wrong statements as you provide in your nonsensical postings. You know nothing about science but have the arrogance to claim that all climate scientists are either wrong or lying.
Get treatment.
Ian -
Wow, thanks for that link. You'd think someone would get tired of being corrected by several people on the same topic at the same time in multiple places, but I guess Vernon just enjoys the argument, and isn't actually interested in where his analysis has gone wrong.
Hope you had a good time, Vernon, I'm done playing your game. I've wasted too much time on you already.
Coby,
I know your policy on your blog is not to silence competing views. Normally, I would not ask that anyone not be allowed to present deferring views of the science and the studies that support their claim. I do however want to post a complaint about Ian Forrester. So far he has not discussed the science or presented studies to support any position. All I see is him making demeaning personal attacks on anyone he does not agree with. This is a science blog, so could you enforce a limit on these attacks and move the focus back to the science. I do not mind if people get caught up in the moment and the conversation gets a little emotional, after all most everyone posting here is passionate about the science.
I know we rarely agree on scientific issues but I have always found you to be a civil opponent. Can we get the pointless personnel attacks eliminated?
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
It was good to revisit some studies and look at new ones during this conversation. I thought some of Vernon's points were valid, and his rejoinders led me to learn that there is still a sizable debate in the literature over which hemisphere leads. From the Vostok cores it was thought that southern insolation triggered global changes, then northern lead was popular, and now it has drifted to a positing that south or both lead. In the latter case, a two-step process that starts in one hemisphere with a slight rise in temperatures, followed by an amplification when orbital variation moves to the other hemisphere - the 100 k/yr signal being triggered by both hemispheres one after the other (with ~ 20 k/yr procession).
Those details have no impact on the basic thrust of the top post, which is to do with post orbital amplification. All the post-1990 papers I've read examining relative contributons to warming agree that insolation changes are too weak to cause much of it (from < 1% to 20%, the mean being 10 - 11%). 80 - 99% of the warming in an interglacial comes from forces other than insolation changes. Consistent with the papers I cited above, there is general agreement that GHGs account for about 50% of the total warming, CO2 comprising a third. GHG warming hastens ice-sheet retreat, and therefore take a share of the ice response in the overall warming.
This general agreement is unaffected by lag profiles, even towards deglaciation, and the saw-tooth shape of ice age cycles is consistent with the response time of carbon outgassing (fast/ocean) and sinking (slow/geological absorption). Even disregarding work in this milenium positing no lag during the onset of glaciation, the complex feedbacks associated with glacial changes (fresh water pulsing, ocean overturn, plant cover dynamics, ice sheet changes, silicate coverage etc) may account for a CO2 drawdown lag. The coarse, low-resolution graphs do not capture short-term variations (< 1000 years). There is a great deal of +/- activity at the peaks and troughs not reflected in this conversation - and only beginning to be understood in the literature - that may explain the phase lag into glaciation. If it did, indeed occur.
It may interest some to know a climate system lag was posited as early as 1976, well predating the IPCC. Hansen was co-author author of a 1990 study (I cited it upthread) that mentioned the possibility of climate system phase-lag (ice sheets and GHGs). Ice age studies were definitely not a basis for AGW theory - that was posited 70 years before GHG response in ice ages was examined much. Vernon, your narrative on re-inventing AGW theory to fit burgeoning knowledge on ice-ages doesn't match the chronology of scientific understanding, nor does it reflect the physical core of the main theory. Ice-age studies have by and large been connected to AGW via verifying climate sensitivity, which has never depended on the timing of forcings.
I am not interested in persuading people one way or the other on AGW. I am only interested in establishing the progress of the science and the weight of current opinon. This seems like the objective way to aproach specific issues twoards forming an opinion on the general theme, but I'm not championing a cause..
Vernon and crakar: there are always outlying papers and views. If you emphasise those without understanding and crediting the mainstrewam view, then I'm not sure that your purpose is an objective analysis. Vernon, I'm not trying to argue the merits of AGW, and am not inclined to follow the digressions you offered. Perhaps we'll pick them up in more appropriate places.
Ian and Adam: you may also be gripping your position to tightly. At one time I used care about persuading people to my view, but I found that this earned me more grief than was worth it, and my own objectivity was occluded by furstration.
It's probably presumptuous of me to offer advice (perhaps even patronising, although I don't see myself as some debate guru), but I've found a detached approach, rooted in a real curiosity in the science, has yielded a better discourse from me, elicited similar from people who disagree with me, and that the discourse between us progresses faster from point to point and more effectively as a result. Or, IOW, butting heads gets you a sore head. :-)
Ultimately, what happens in the bottom of threads at blogsites isn't going to much effect the world of policy. It's no loss of pride simply to walk away, either.
And with that, I don't think there's much more to be gained slugging it out here. On certain aspects, the debate goes on in the literature, and that, to me at least, is fascinating.
Peace.
Vernon, there are not "two sides to science". There is what is described in the peer reviewed scientific literature and your rubbish. As I have pointed out on two other blogs your interpretation skills are zero. Whether this is deliberate or just due to your ignorance I don't know but your repeated scoffing of real science is pathetic.
Coby is free to do as he wishes with my comments about your lack of ethics, arrogance and pigheadedness. I just want to point out to others that you repeat the same nonsense over and over again on several blogs (those that you have not been banned from).
To Adam,
Thanks for the clarification, although you do realise that an increase in temp will also cause an increase in water vapour which is a much more powerful GHG. Most people here seem to not mention WV but we should keep in mind that WV plays a crucial role in the AGW theory and without WV the AGW theory would not exist.
The graph i showed clearly shows that at no time does CO2 control the temps so i am still with Vernon on this one and fail to see how without any evidence anyone can come to the conclusion that after an 800 year lag CO2 drives the climate, which is essentially what you are saying. Maybe you are right and we should agree to disagree as always.
By the way Barry's analogy of feed back is in fact very poor (no offense Barry) The microphone rxs an audio signal which sends it to the amplifier which amplifies the audio signal and is reproduced via a speaker this audio signal is then rx'ed by the microphone at a higher amplitude (measured in decibels) it is then sent to the amp which amplifies it etc, etc.
To fix the problem you simply move the microphone away from the speaker, the climate works obviously in a much more complex and different way. But to explain a simple positive feed back it works ok.
On the subject of feed backs, Vernon asked what stops it from moving to an extreme state. I do not believe his question was answered fully or clearly. Adam i think you said we have multiple inputs that stop this? If so then would that not suggest that CO2 is not the most powerful driver as you suggest. It would suggest to me that we have multiple inputs that push the climate in many different directions, some up and some down.
Sometimes we have more pushing up so temp goes up, sometimes we have more pushing down so temp goes down. And all the while CO2 lags the temp by about 800 years.
barry -
No offense taken, and your statement certainly wasn't patronizing. It is something to keep in mind, and arguing with people like Vernon and Crakar isn't likely to gain you anything (and as you mention, is more likely to result in frustration and loss of objectivity). That being said, I don't think anything I wrote was too far off base, though I'll leave that for others to judge.
crakar,
But to explain a simple positive feed back it works ok.
That is precisely what I was doing. It seemed upthread that the concept of feedback was misunderstood. The analogy works WRT to the subject in that whether turning up the amp, or bringing the mic (guitar in my example) closer to the speaker, both have the same effect of producing the feedback if the initial conditions are right (proximity close enough that either change of state produces the effect = sensitivty of the climate system to various forcings). It's not just one or the other, and all examples are a property of physics.
And with respect to reversing the feedback effect, either turning the amp down or moving the the guitar further away from the speaker will do the same job.
Not a perfect analogy, of course (none are) but sufficient to describe feedback. And yes, there are multiple feedbacks in ice age dynamics, many not very well understood at present. But the large scale feedbacks have clearer signatures and there is general agreement on those in the literature in line with the argument in Coby's post.
To add to my growing collection of scientific studies on ice age climate dynamics, are there any post-80s peer-reviewed studies on ice ages positing a small contribution of greenhouse gases to interglacial warming? Please post them here. I've been unable to locate any.
Please, no blog posts from unqualified people, and no orthogonal work.
Ian,
your understanding of science appears to be flawed to me. Science is not a monolith, but rather it is made up of many competing views and ideas. It is the search for the truth, often by the very competition you decry that eventually leads to the truth. Every thing I have quoted was peer reviewed and published science, just because you do not like it does not devalue the work. You made the claim that your a scientist, and I do not doubt you. While I am only an engineer, I do not understand why you are adverse to a frank discussion of the science or even why you do not go with first sources, but chose to quote advocacy sites.
I do not consider myself to lack ethics, be arrogance but I do concede that I am can be stubborn. You have no basis for making the first two claims other than seems to be your standard mantra when you are confronted with facts and studies. As to the stubbornness, that seems to be a characteristic of almost all the posters on all the sites.
As to your complaint that I discuss the same issues on other sites - I have to ask, why is that a problem? So far I have not found anyone on any site that can address my principle argument, namely that the current GCM's are either wrong, or we are not having global warming. Since, it is evident that we did do a 20 year warming period, the models appear to be wrong.
Yes, I got banned on one blog for saying that the Wegman report showed that Mann et al's use of statistics was flawed. When quoting the premier statistician in America, on a panel of premier statisticians, when they find that the statistical methodology was flawed causes you to be banned, well, that says more about the site than about me.
Vernon, science is about honesty. That means you don't misquote, you don't cherry pick and you don't quote a paper which says the opposite of what you claim. You are guilty of all of these. These are considered major acts of malfeasance in science. I don't know what your background is but it is obviously not in science. Science is one of the most honest and honorable disciplines around (at least until the anti-science people got started).
If you want to be considered worthy of having discussions with you will have to leave your baggage at home and start afresh.
If you continue to repeat your anti-science tactics I will expose you on it every chance I get.
To others who may not agree with my approach, sorry, but that is the way I am. I have spent over 40 years in science and I will not have it besmirched by the likes of Vernon et al.
barry,
I have to disagree with you on our general knowledge of the climate drivers and feedbacks. The IPCC 4th AR says that the level of scientific understanding is medium for ozone, medium to low for surface albedo and direct aerosols, and low for Stratospheric warer vapor, total aerosol, clouds, linear contrails, and solar irradiance. What is really surprising is that the IPCC makes no claim of any scientific understanding for water vapor.
Oh, and please do not do what Lorius et al (1990) did. Start off talking about GHG and then switch the discussion to CO2.
Stott et al (2007)http://www.sciencemag.org/cgi/content/abstract/318/5849/435
Deep-sea temperatures warmed by 2°C between 19 and 17 thousand years before the present (ky B.P.), leading the rise in atmospheric CO2 and tropicalâsurface-ocean warming by 1000 years. The cause of this deglacial deep-water warming does not lie within the tropics, nor can its early onset between 19 and 17 ky B.P. be attributed to CO2 forcing. Increasing austral-spring insolation combined with sea-ice albedo feedbacks appear to be the key factors responsible for this warming.
Soon (2007)
http://bellwether.metapress.com/content/6024h28209l41257/
A review of the recent refereed literature fails to confirm quantitatively that carbon dioxide (CO2) radiative forcing was the prime mover in the changes in temperature, ice-sheet volume, and related climatic variables in the glacial and interglacial episodes of the past 650,000 years, even under the "fast-response" framework where the convenient if artificial distinction between forcing and feedback is assumed. Atmospheric CO2 variations generally follow changes in temperature and other climatic variables rather than preceding them.
Monnin et al (2004)
http://epic.awi.de/Publications/Mon2003a.pdf
A new chronology for the Taylor Dome ice core established through CO2 synchronization reveals that the accumulation has changed substantially during the Holocene, with a long-term increase that shows little relation with the Temperature history. Many timescales using ice flow models, especially those for Antarctic cores, are based partly on the assumption that the accumulation rate varies as the saturation vapor pressure over ice and is therefore a function of local temperature. This assumption is clearly not valid at Taylor Dome, and is likely to be substantially incorrect at other sites as well, notably in locations such as Law Dome and Siple Dome, which are at relatively low elevation and near coastal regions. At more-inland sites such as Dome C, independent validation of the ice core timescales suggests that the assumption is reasonable; however, it is unlikely to be strictly valid and caution is urged in applying it.
Ahn et al (20050
http://gradworks.umi.com/31/85/3185926.html
On the basis of a combined study of noble gases (Xe/Ar and Kr/Ar), electrical conductivity, and Ca2+ ion content, for the first time it was confirmed that substantial CO 2 diffusion through the ice occurs on timescales of thousands of years. The product of the diffusion constant and the solubility was obtained as 4.3 (±2.1) à 10â21 m2s â1 molCO2 mâ3ice (PaCO 2)â1 at â23°C. This work shows that the smoothing of the CO2 record in the core by diffusion is one to two orders of magnitude smaller than the smoothing induced by the gas age distribution at the depth of 287 m (gas age = 2.74 kyrBP, thousand years before 1950) in the Siple Dome ice. Further results of this research found that Siple Dome CO2 concentrations during the last deglaciation and in the Holocene are at certain times greater than those in other Antarctic ice cores by up to 20 ppm (μmol CO2/mol air).
Basically, what I am presenting is that what we think we know is constatly changing.
Ian,
I have never considered you worthy of having a discussion with. You never present anything. You only point to advocacy sites.
Just to make sure I have this right. Referencing a study as a source for a specific fact is what you consider a major act of malfeasance in science. Now I know you are not in science and do not have a clue. If I reference a specific paper as the source for a specific fact, that is not malfeasance or misquoting despite what you wish to believe.
So, please, point to where I have misquoted a study.
Vernon, I have wasted enough of my time on you here. However, I will bring your dishonest ways to any other site that you try to post your scientific nonsense on.
I have been a scientist for over 40 years so I know what I am talking about when I call you you distributing your nonsense.
You would get thrown out of any decent science school if you tried your tactics there. Scientists are not entitled to their "own opinions". Scientific consensus is built up on a frame work of agreed on laws, definitions and facts. Do you have a different opinion on what defines a metre, what defines a second, what makes up water? Of course not. The science of AGW is similarly built up on layers of agreed and established principles.
There is hardly one paper in the scientific peer reviewed literature which has any data which disproves these established principles.
You are nothing but a denier troll.
Ian,
You are not a scientist, lie about it as you want. I will be happy when you quit following me a round and being a liar. You make slurs and defamatory posts but never back up your crap. You are the worse kind of troll.
Fool, the IPCC quite plainly states that we have low scientific understanding of Stratospheric water vapor, tropospheric water vapor, solar irradiance, and linear contrails. We have medium to low understanding of aerosols, and surface albedo. We only have medium understanding of Ozone. We do not even have high understanding of all the GHGs. Water vapor is the strongest and most prevalent GHG and we do not fully understand water vapor or clouds.
It has just in the last few years been proven that UHI is a significant contributer to regional and potentially global instrumented temperature trends.
Recent studies have shown that tree rings are not good temperature proxies and many issues that have yet to be addressed have been identified.
The statistical methods used in the temperature reconstructions have been found to be flawed and to not recreate the low frequency variability.
Finally the GCM's predict that for global warming, there will be polar amplification, but there is not.
This is all out of the IPCC or other peer reviewed published reports. You call me a liar when I present peer reviewed studies that back up my position.
You are a clueless troll.
Vernon is showing his true colours. He doesn't have a clue about me but is willing to lie that he knows I am not a scientist. Vernon, you are as wrong about that as everything else you write about. It must make you feel great living in a make believe world and making fun of everyone who tries to bring you into reality.
By the way, you keep claiming that I never offer science cites. You refuse to discuss the cites I gave showing you that you are completely wrong in your assertion that there is no Polar amplification. You just ignore any science which refutes your denier viewpoints. Typical of all AGW deniers.
You are scraping the bottom of the barrel with your latest list of "scientific" findings, they have all been debunked many times.
You are pathetic.
i have read in quite a few places about the microphone near the speaker analogy, and it is just completely wrong, but it does highlight some conceptual problems.
the microphone is connected to an amplifier with an external power source, if you remove that power source, then the output will never be greater than the input ie all that feedback does is either dampen the waveform (negative) or bring it closer to a unity state of 0db (positive). it can never be greater than the input. there is no amplification of any form of energy ever, only energy conversion. put quite simple, energy cannot be created or even destroyed for that matter.
now the theory is that co2 is converting more electrical energy into heat energy by a positive change in concentration. and this part is correct. but it is important to remember that the energy is still within the system.
the next step is to work out what effect the extra co2/ heat energy has on the overall temperature.
if we look at history where co2 and temps have both been higher and the system was fairly close (suns output), we see a driver other than co2 that starts heating, we also see a drop in temperature over a given length of time. now if we refer back to the system and feedback, we can see that for co2 to be able to alter the temperature more than the original signal there needs to be another energy source introduced that was not there before. we know that there is no new energy source, only what co2 can do itself, so from this the cooling proves that co2 does not drive temperatures even at higher concentrations.
where is the flaw in the logic?
Barry post 134,
Sorry misunderstood your post a little, i think we both agree on the same thing re feed back analogy.
In regards to ice ages and their cause, i had a really good study by NASA which claimed the MC was not a sufficient forcing to cause an ice age, think it was post 1980 but have lost it somewhere. I did send it to Coby for his thoughts, maybe he has still got it?
I have this link which gives us a quick look at the various theories and thier related studies
w.w.w.sentex.net/~tcc/iceage.html
None of these mention GHG's not that that means anything some are pre 1980.
This one suggests the Earth moves into and out off debris in space which i suppose acts to dim the suns rays causing cooling etc.
w.w.w.lbl.gov/Science-Articles/Archive/ice-age-sediments.html
This one shows the oceans warmed from the bottom up first suggesting that GHG's did not drive the Earth out of the ice age
w.w.w.worldnetdaily.com/news/article.asp?ARTICLE_ID=57895
The only study i can find that references the role of GHG's is this one, they change the dates of the last ice age to when the CO2 levels were very low as opposed to being high (in the 1000's ppm range)
researchnews.osu.edu/archive/earlyice.htm
So Barry, we have a lot of competing theories to choose from which is why i say "something" happened to cause an ice age and "something" happened to end it. I am sure that GHG's play a role but the theory being portrayed here by some that CO2 played no role for 800 years and then "took over" is at best absurd and is nothing more than wishful thinking.
If you have a study which supports the CO2 does nothing for 800 years then takes over i would be very interested in having a look at it.
Cheers
Crakar
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Thanks!