(Part of the How to Talk to a Global Warming Skeptic guide)
Objection: In glacial-interglacial cycles, CO2 concentration lags behind temperature by centuries. Clearly, CO2 does not cause temperatures to rise; temperatures cause CO2 to rise.
Answer: When viewed coarsely, historical CO2 levels and temperature show a tight correlation. However, a closer examination of the CH4, CO2, and temperature fluctuations recorded in the Antarctic ice core records reveals that, yes, temperature moved first.
Nevertheless, it is misleading to say that temperature rose and then, hundreds of years later, 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 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 (the Milankovich and other cycles) caused greater amounts of summer sunlight to fall in the northern hemisphere. This is a 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 further warmth, in a feedback effect. Some number of centuries after that process started, CO2 concentrations in the atmosphere began to rise, which amplified the warming trend even further as an additional feedback mechanism.
(You can go here for a discussion of exactly this question by climate scientists, 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 contributed to them -- and according to climate theory and model experiments, greenhouse gas forcing was the dominant factor in the magnitude of the ultimate change.
This raises a warning for the future: we may well see additional natural CO2 come out of the woodwork as whatever process 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.
On ‘climategate’
What to make of the new climate poll
Comments
View as Flat
Whiskerfish Posted 6:08 pm
26 Dec 2006
After CO2 and temp rose approx 130k BP (see graph), what brought them back down again so (relatively) sharply?
A very curious
Whiskerfish
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dobermanmacleod Posted 9:24 pm
26 Dec 2006
Some trigger (like volcanic eruptions) starts the ball rolling by boosting greenhouse gas levels.
A warming earth turns carbon sinks into carbon emitters. As they starts to slowly emit carbon, it warms the climate, which cause the carbon sinks to emit faster (i.e. feedback loop).
55 million years ago (the PETM), a trigger caused a severe episode of runaway global warming. 500 million years ago (the "Great Dying") a trigger caused a very bad episode of global warming that killed 90% of the life on earth.
Mankind is emitting CO2 much faster than past runaway global warming triggers. The stronger/faster the trigger, the worse the global warming episode. Another factor is the amount of carbon stored in carbon sinks since the last episode emptied them.
After the carbon sinks have ceased emitting their supply, the CO2 gradually is absorbed by the ocean, rock, and organisms. This carbon cycle has repeated many times, swinging wildly when triggered.
By the way, climate models fail to include feedback loops, so underestimate the speed of the current episode we are triggering.
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froggy Posted 1:26 am
27 Dec 2006
we are emitting co2 at a rate AND context like no other time in history. unless dinosaurs' were burning coal millions of years ago, i would say that this situation is different from previous CO2 events.
ofc then we need to discuss the where and when fossil fuels come from...and sometimes the argument is that 'but how can that happen cuz the planet is only 5000years old?'...:)
froggy
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Coby Beck Posted 4:30 pm
27 Dec 2006
Perhaps Andrew Dessler will read this thread and help out here, but my only explanation for the cooling is that the same process worked in reverse. Orbital changes resulted in lessening sunlight in the north (where most land is) allowing ice sheets to regrow towards the south, with the resulting albedo feedback. Cooling oceans began to draw CO2 out of the air, another feedback. The cooling process was much slower than the warming process because ice sheets generally form much slower than they melt and perhaps CO2 can rise faster than it can be drawn down.
AFAIUI, the whole business is not really well understood.
Invent a clever saying, and your name will live forever!
-- Anonymous
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amazingdrx Posted 11:34 pm
28 Dec 2006
Arctic ice reforms, starting up the gulf stream conveyor, land areas warm up melting ice. Land absorbs more solar heat, plants lower cO2 levels and the whole system stabilizes into a human friendlier state.
Humans burn everything they can find that will burn (they are down to burning dung in many areas now, having burned all the trees), fire is shiny and warm. Then they find stuff that will burn underground! stored for milenia! let's burn this stuff and make lots of money! they cry!
CO2 levels spike like never before from this extra combustion. The climate heats melting the arctic ice, the conveyor stops.
And so it goes. A mixture of Vonnegut and Seuss maybe more effective in getting through the haze surrounding the faithbasers.
Smog makes their skulls grow thicker turning their brains into mush? That might be it. A natural reaction, the body is trying to protect the brain, but instead destroys it.
http://amazngdrx.blogharbor.com/blog
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Entrylevel Posted 2:05 am
29 Dec 2006
However, there is an alternative hypothesis. Sunspot peak frequency corrrelates 95% with temperatiure rise and coupled with the Danish CLOUD experiment, there is a case to stop the bandwagon of anthropogenic global warming before it destroys our economy.
The effect of implimenting Kyoto would be disaster for you and yours. This is a case of needing to treat symptoms of global warming as they occur, if they are serious enough, without invoking Big Brother government to attack complex causes. The extremist model is not the only hypothesis. There are serious scientific questions. The spectal line of CO2 that is active in absorption is saturated. Additional CO2 cannot cause more warming.
Francis T. Manns, Ph.D., P.Geo. (Ontario)
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amazingdrx Posted 3:09 am
29 Dec 2006
Even if this were true (flying in the face of all the peer reviewed research), it doesn't change anything.
The current rate of climate change is on the verge of becoming exponential. Look at the graph.
As ice melts more solar energy is absorbed, then more permafrost and methane hydrate sea floor ice release more methane. Drought causes photosynthesis to stop in a wider and wider band around the equator. That soaks up less cO2.
GHG levels must come down or we are literally history. And its got to happen quickly, no time to dawdle over denier propaganda now.
You all are in the same position appeasers were during WW2 now. Trying to keep US out of the fight.
http://amazngdrx.blogharbor.com/blog
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GMB Posted 7:38 am
01 Jan 2007
Look I assume that CO2 might cause some warming. But you are wrong here to suggest that Peer-reviewed-research shows CO2 leads to significant warming.
It appears to be too slow and/or feeble to effect things very much at all over time scales we normally worry about. I say this because it barely shows up in the data contrary to your glib claims here.
And we ought to deep-six this peer-review obsession anyway.
But do go ahead?
Do give us some examples of this research that you are talking about.
It doesn't exist.
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Brudaimonia Posted 1:19 pm
01 Jan 2007
Heh heh, that explains a lot.
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Coby Beck Posted 4:54 pm
01 Jan 2007
Peer reviewed research (you are free to not care about the quality of your information, but you made a claim about this) says that climate sensitiity to 2x CO2 is 2.9+/-1oC. This does not include feedbacks from melting ice caps or carbon cycle feedbacks adding to anthropogenic emissions.
Your claim that the observed warming shows there is not much sensitivity to CO2 is covered here:
http://gristmill.grist.org/story/2006/11/9/223615/983...
Invent a clever saying, and your name will live forever!
-- Anonymous
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GMB Posted 1:22 am
02 Jan 2007
And the research that says this is all bogus.
Which is a failing commentary on Peer-review.
I mean it doesn't even have a thing to say about what time-scales we might be looking at to support such a thing.
And besides that its entirely baseless and without the evidence to support it.
Without clicking your link I assume you are looking at the Annan study using Bayesian statistics to polish a turd.
This guy is like Beethoven trying to dress up Mary had a little lamb. He does a great job of it to a point.
Like trying to dress up bad guitar playing with sophisticated audio engineering.
Look if the above was actually true in any sort of decadal or century-long time period we would be very fortunate indeed.
I almost WANT IT to be true.
But the data just doesn't support it.
Not unless we are talking about keeping levels high for thousands of years.
I'll admit the POSSIBILITY of something of that nature.
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MarkB Posted 3:02 pm
08 Feb 2007
Am I way off track? I haven't seen this explained anywhere, so feedback or links will be appreciated.
Cheers, Mark.
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Coby Beck Posted 1:45 pm
13 Feb 2007
Sorry for the tardy reply. Yes, I think that is the best way to put it, the record is consistent with the theory. I would correct you though that this record does not "prove" CO2 can't lead, only that it indicates that it did not lead during these cycles. There are other historical examples of CO2 leading (PETM, Decaan Traps).
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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egbooth Posted 4:31 am
07 Mar 2007
A very important feedback (at least on geologic time scales) is chemical weathering. CO2 is a necessary component in the dissolution of carbonate and silicate minerals. Since the dissolution of these minerals increases with temperature (and precipitation), this mechanism acts as a negative feedback. But before you go out and start digging up rocks and priming them for dissolution, remember that this process is important on geologic time scales and is not an effective geo-engineering solution.
For more information, see this article in Science magazine, which describes how we are actually seeing more chemical weathering these days in the Mississippi River basin through increased alkalinity in water samples taken by the USGS:
Ittekkot, V. (2003). "A new story from the ol' man river." Science 301(5629): 56-58.
Also, you could just do a Google search for "chemical weathering", I suppose.
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Alastair Posted 7:46 pm
09 Mar 2007
This certainly doesn't appear to be the case from the graph, the temperature rise looks relatively linear, this suggests that CO2 concentration has no significant effect on temperature over and above that of the sun.
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Coby Beck Posted 3:38 am
10 Mar 2007
BTW, it is not my theory, I'm merely trying to explain what current climate science thinks. I don't believe I did say that "CO2 becomes an increasing influence" I only said that GHG forcing dominates the overall temperature change.
Please also keep in mind that the climate is a complex system, orbital inclination and CO2 are only two out of many factors.
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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Delay And Deny Posted 4:01 am
10 Mar 2007
You write:
So it is correct that CO2 did not trigger the warmings, but it definitely contributed to them -- and according to climate theory and model experiments, greenhouse gas forcing was the dominant factor in the magnitude of the ultimate change.
Here, you admit that you are wrong, and then you make yet another assertion about how important CO2 is. Why? Where's the research? One minute you tell me its driven by CO2, then you admit that no, it's not. But that CO2 "helps it along". Why are you guys so obsessed about CO2. It's over, get on with it.
Global Warming is not anthropogenic. Let's get out in the sun and enjoy some volleyball in October!
The Texeme Construct offers international text memetics construction and textcasting services.
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Alastair Posted 12:44 am
11 Mar 2007
"Time for debate is over, it's time to act"
- The debate is definitely not over no matter what the media and politicians will have you believe. There are gaping holes in the CO2 theory of climite change that cannot be ignored. The fact the Temperature leads and doesn't lag is only one of them, I agree with the previous poster that it sounds very much like you are clutching at straws.
"Experts unanimously agree that climite change is caused by man made CO2"
This is simply not true. Many experts do not agree with the "concencus" and have had their names put down on papers when they did not agree with the findings. I am also when I hear this comment on TV or in the papers but names are never mentioned and those with opposing views are never publicised.
I also think it's a bit arrogant for you (or whoever runs this website) to be refering skeptics silly or naive when by your own admission you do not fully understand the science behing your words. The skeptics still have a very strong case and should not be treated like holocaust deniers.
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Coby Beck Posted 11:38 am
11 Mar 2007
But as for "The skeptics still have a very strong case", um which case is that? Current change is solar variations? Cosmic Rays? A natural, unstoppable 1200yr cycle? Not even happening? Stopped 8 years ago? Internal variability?
These are all "skeptic" theories and are all mutually contradicting, even though the same "skeptics" often promote two or more of them simultaneously.
This is called grasping at straws and is simply mental gymnastics in order to avoid an unpleasant reality.
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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Alastair Posted 6:51 am
12 Mar 2007
I don't believe I did say that "CO2 becomes an increasing influence" I only said that GHG forcing dominates the overall temperature change.
That comment itself is mutually contradicting. If CO2 does not become an increasing influence, how can it dominate the overall temperature change? You've already acknowleged that CO2 is not important at the beginning of the cycle (low concentration), therefore if your theory is true CO2 must become an increasing influence at higher concentrations, this would be seen as an increasing differential or slope of the curve. Unless it can be proved that higher CO2 concentrations lead to a higher temperature differential, it would seem very unlikey that CO2 is an important factor in determing global temperature. Without this proof, the theory of CO2 dominance on global temperature falls apart.
I don't deny that CO2 will have some effect on global temperature, even the staunchist skeptics will admit this because CO2 is a greenhouse gas. But we are talking orders of magnitude here. CO2 forms only an order of about 1% of the greenhouse effect, a inrease in temperature of 0.1 degrees with sea level rises of millimeters or centermeters due to human activities is far more likely than global catastrophy.
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Coby Beck Posted 6:30 am
14 Mar 2007
Your implication was that my explanation meant T should rise faster and faster as "CO2 becomes an increasing influence". CO2 obviously must increas from 0 influence to one greater than than initial orbital forcing, but I do not say it continues to increase, that is your extrapolation. Now this is really a bit too much semantic quibbling, isn't it?
The forcing effect of 100ppm CO2 added to the low of 180ppm is a greater forcing effect overall than that provided by changes in NH insolation caused by Milakovich cycles. You'll have to run a GCM or find a detailed paper to see the changes in radiative forcing over time of the various factors.
As for your suggestion that we should see an increasing slope as CO2 rises:
a. how do you know it isn't there? This is hard to determine, especially just eyeballing the graph.
b. you are over simplifying a complex system
c. CO2 has a logarithmic relationship with forcing, not linear.
"CO2 forms only an order of about 1% of the greenhouse effect"
Wrong.
http://gristmill.grist.org/story/2006/12/22/222357/40
This is a specific and technical scientific question, not a matter of opinion.
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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solman Posted 6:08 pm
15 Mar 2007
You have two signals A and B which are tightly and very consistently correlated over a very long period of time across a wide variety of conditions, with signal B always following signal A by a fixed interval of time.
This is a VERY powerful piece of evidence in favor of the hypothesis A causes B. In any other discipline, suggesting otherwise would get you stabbed in the heart with Occam's razor.
The alternative hypothesis:
First: C (which we can't identify or measure) caused a little A,
Later: C caused B
Finally: B caused a lot of A
is not impossible, but I am utterly unconvinced, and this is at the hear of my skepticism.
If historically CO2 was caused by some external cause other than temperature, what is it?
The rapid current rise in atmospheric CO2 is caused by a disruption in the equilibrium of the Carbon cycle. This disruption could be, in part or in majority, humans putting extra CO2 into the atmosphere.
But it also could be, in part or in majority, the same thing that caused the previous increases in CO2.
The speed of the CO2 increase suggests that whatever is breaking equilibrium began with the industrial age of man, but man has changed the environment in numerous ways.
The destruction of plant life, and the dimming of the sun from pollution have certainly reduced photosynthesis.
Perhaps our actions have somehow resulted in the destruction of vast numbers of microbial photosynthetic ocean dwelling creatures (well actually we know they have, but I mean that perhaps the die off had a orders of magnitude larger impact on CO2 than we thought).
Absent a debunking of the default hypothesis for this graph (that Temperature increases and decreases cause increased and decreased atmospheric CO2), its not reasonable to look at the data for the past century and say "CO2 causes temperature". CO2 and temperature have both risen, this graph says that causality goes the other way.
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Zarkov Posted 8:59 pm
15 Mar 2007
yes indeed, direct evidence.
The ocean micro layer is a soup of toxics, including evaporation retarding petroleum oil. Its a total mess.
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Coby Beck Posted 1:08 am
17 Mar 2007
I don't understand how anyone can actually read this article and somehow think that climate scinece denies temperature rises cause CO2 rises. So you have attacked a strawman.
As for "the CO2 rise could be natural....
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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Alastair Posted 9:51 pm
17 Mar 2007
http://environment.newscientist.com/channel/earth/climate ...
Therefore the relationship between CO2 and temperature can be explained scientifically without even mentioning the greehouse effect.
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solman Posted 10:50 pm
17 Mar 2007
Most people are introduced to global warming with the following argument:
Here is a theory for how increased CO2 can cause increased temperature.
Here is a graph of CO2, it is going up rapidly.
Here is a graph of temperature, it is going up rapidly.
The conclusion is then drawn that increased CO2 is causing increased temperature.
Mentioning the theory behind the green house effect, but some how forgetting to mention anything about higher temperatures causing higher CO2 is a rather serious omission.
I certainly don't think it disproves the mainstream theory of climate change, but it offers an alternative explanation for the data, and ruins this chain of logic.
As far as the CO2 rise is natural thing:
The article basically says:
We emit CO2.
The timing is anthropogenic.
#1 is hardly convincing. There are a dozen theories about global cooling that could be similarly validated if not for the slight problem that the earth is getting warmer.
I don't disagree with #2. The rate and timing of temperature change is compelling evidence to me that its anthropogenic. That doesn't mean its CO2. There are a great many ways in which man has changed the world he lives in.
As we see here, anything that increases temperature, would be expected to increase CO2, and the absence of a time lang can easily be explained by the extreme rapidity of the current temperature increase relative to the graph.
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Coby Beck Posted 2:14 am
22 Mar 2007
http://gristmill.grist.org/story/2006/12/22/224450/84
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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Coby Beck Posted 2:17 am
22 Mar 2007
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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Alastair Posted 7:05 am
23 Mar 2007
http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm
Here's why. I'm 99% sure that these models were produced using only emperical data, not using scientific first principals. What they did is they took the input variables such as CO2 concentration and natural variables (eg solar radiance) and produced an emperical equation of best fit to match the observed global temperature. This is very easy to do for anyone who is a competent user of Microsoft Excel but is of no use in predicting future temperature because it doesn't consider cause and effect or scientific first principals.
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Coby Beck Posted 11:26 am
24 Mar 2007
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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Zarkov Posted 11:12 pm
24 Mar 2007
...assumptions that the cause of the global climate change was a natural event. Oh yes, the level of greenhouse-gases was unnaturally high, but the process of future global climate readjustment it was assumed, was tightly correlated to the same processes that readjusted the overpressure of greenhouse-gases in the past.
This assumption is erroneous. Worse, it is fatal, and it does not need to be said, it is just plain BAD SCIENCE.
The petroleum oil in the marine micro layer is NOT NATURAL, and no natural climatic process can be invoked to remedy the consequences of the oil reducing the water evaporation rate. Negligent business/governments put it there, we must remove it to fix it.... if that is possible.
But hey, THEY know what is happening,,,,, and THEY do not want anyone to see what is really happening.
Big Oil and various governments are conspiring to keep a lid on this. Its a re-run of the tobacco war, where in place of single individual lives being placed at risk, it the very existence of LIFE on Earth that is being placed at risk.
Revolt while you are still able. Scream your anger from the roof tops. The end-times are here, and God couldn't care any less.
Be angry for the children.
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Alastair Posted 6:26 am
25 Mar 2007
but 100% wrong. How can anyone be so sure of themselves without having done the least bit of investigation?
I can be so sure of myself because as you said earlier, the climate is an extremely complex system with many variables and positive and negative feedbacks such as cloud cover and polar ice volumes. That someone can produce a model that can near perfectly predict the temperature over a century is too remarkable to be true when we are talking about global climate which is one of the most complex systems imaginable. It is very clear to me that the model must be empirical to get such a perfect result. Empirical models are only meaningful if the correct assumptions are made otherwise they are meaningless. For example, I could produce a model showing that global temperature is driven by the stock market, but this would be nonsense because the assumed relationship between the two variables is wrong.
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bzn Posted 11:22 am
30 May 2007
but 100% wrong. How can anyone be so sure of themselves without having done the least bit of investigation?
Firstly, I want to say that this sounds really arrogant to me Coby. Alastair admits to some kind of limited uncertainty, and you then respond with complete certainty that he is wrong. Yes yes, I am making an ad hominem comment here, I know, but let me put this forward as an outsider observer: IMO Alastair sounds a lot more balanced and willing to stick to the arguments, whilst also admitting uncertainty, than you have demonstrated in this thread. This is just a suggestion from a GW know-nothing individual that was swayed by "An Inconvenient Truth", and then also swayed to be a little more questioning by "The Global Warming Swindle" - the way you are responding to criticism does not help your case.
I can be so sure of myself because as you said earlier, the climate is an extremely complex system with many variables and positive and negative feedbacks such as cloud cover and polar ice volumes. That someone can produce a model that can near perfectly predict the temperature over a century is too remarkable to be true when we are talking about global climate which is one of the most complex systems imaginable. It is very clear to me that the model must be empirical to get such a perfect result. Empirical models are only meaningful if the correct assumptions are made otherwise they are meaningless. For example, I could produce a model showing that global temperature is driven by the stock market, but this would be nonsense because the assumed relationship between the two variables is wrong.
This is not necessarily true Alastair, from my understanding of Karl Popper and the philosophy of science. There is no such thing as "scientific first principles". Scientific method cannot actually "prove" anything. All science can do is build models from empirical data, and if they successfully forecast future empirical data, take stabs at why they did so, and use those stabs to try and make more models. "Scientific first principles", i.e. "these models keeps generating good predictions so far and is therefore Real/Truth" is scientism (belief), not science (eternal constructive scepticism).
So it is true what you say in your example about potentially producing a model linking the stock market and global temperature in the past. The main thing is, does this model so constructed also predict the future? If it doesn't, the scientist can choose to tweak the model or throw it away. If it does however, there may be a relationship after all that deserves closer examination. When empirical data consistently follows the models, a person that understands real science as opposed to scientism would not dismiss something just because it seems preposterous according to "what is known".
In other words, I think you can be more than 99% sure that the models are empirical, because actually all scientific models are. This is all the more reason why we must be wary of them.
Best,
BZN
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GreyFlcn Posted 2:57 pm
30 May 2007
Claim: Ice cores show that during earlier periods in the Earth's history, rises in carbon dioxide followed increases in temperature, and therefore the current rise in greenhouse gas concentrations has not caused the recent increase in global average temperature.
Misrepresentation: It is well established that analyses of ice core from Antarctic show that local temperature rises during the transition from glacial to interglacial periods, which are triggered by regular fluctuations in the Earth's orbit (and hence its distance from the Sun), were followed some time later by increases in the local average concentration of atmospheric carbon dioxide by up to 100 parts per million. However, the conclusion drawn in the programme that this means the recent rise on concentrations of carbon dioxide and other greenhouse gases could not be responsible for the recent increase in global average temperature is counter to the evidence presented in the scientific peer-reviewed literature.
In particular the programme misrepresented the contents of a paper by Nicolas Caillon and co-authors which was published in the journal `Science' in March 2003. The paper by Caillon and co-authors examined the timing of changes in atmospheric carbon dioxide and temperatures during the Termination III deglaciation event about 240,000 years ago. The authors found that "[t]he sequence of events during Termination III suggests that the CO2 increase lagged Antarctic deglacial warming by 800+-200 years and preceded the Northern Hemisphere deglaciation".
The programme presented a graph to illustrate the results of the work by Caillon and co-authors (to whom it was directly attributed), but which appeared nowhere within the paper. This graph was presented in support of the argument that rises in the atmospheric concentration of carbon dioxide are the result of, rather than the cause of, increases in temperature. However, Caillon and his co-authors concluded in their paper that "the situation at Termination III differs from the recent anthropogenic CO2 increase", noting that "the recent CO2 increase has clearly been imposed first".
In fact, the paper suggested that a fluctuation in the Earth's orbit initiated the increase in surface temperatures in Antarctica, and was followed by a gradual warming of the oceans, which released substantial volumes of carbon dioxide (the volume of carbon dioxide dissolved in sea water decreases with increasing temperature). It also indicated that the carbon dioxide released by the oceans added to the warming of the atmosphere, and contributed to the deglaciation of the Northern Hemisphere. The paper stated that the sequence of events during Termination III is "still in full agreement with the idea that CO2 plays, through its greenhouse effect, a key role in amplifying the initial orbital forcing".
A paper by Urs Siegenthaler and co-authors, published in the journal `Science' in 2005, described evidence from the Dome C Antarctic ice core for lags of 800, 1600 and 2800 years between deglaciations at terminations V to VII and rises in the atmospheric concentration of carbon dioxide, respectively. However, the programme failed to point out that the record of temperature increases followed by rises in carbon dioxide concentration, which are described in the papers by Caillon and co-authors and Siegenthaler and co-authors, all relate to episodes of deglaciation. The last deglaciation on Earth occurred 12,000 years ago, but the current rise in carbon dioxide and other greenhouse gases, such as methane and nitrous oxide, started during the Industrial Revolution in the 18th century ie more than 11,000 years after the last deglaciation.
Furthermore, the programme failed to point out that the rise in temperature and carbon dioxide levels during Termination III occurred over a period of about 5000 years, much longer than the period since the start of the recent rises in temperature and gas concentrations in the 18th century. It also failed to acknowledge the findings of the paper by Siegenthaler and co-authors that "the atmospheric concentration of CO2 did not exceed 300 ppmv [parts per million by volume] for the last 650,000 years before the preindustrial era". As the IPCC Third Assessment Report in 2001 pointed out, the scientific evidence shows that the atmospheric concentration of carbon dioxide prior to the Industrial Revolution was 280+-10 parts per million, and has risen continuously ever since, reaching 377 parts per million in 2006 ie the atmospheric concentration of carbon dioxide has risen in the last 250 years to a level today that is 25 per cent higher than the maximum recorded during a period of at least 650,000 years before the Industrial Revolution.
The programme clearly misrepresented the conclusions of the paper by Caillon and his co-authors, as well as the evidence that the recent increase in global average temperature is following a rise in the atmospheric concentrations of greenhouse gases.
http://www.climateofdenial.net/?q=node/3
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Alastair Posted 7:07 am
07 Jun 2007
So it is true what you say in your example about potentially producing a model linking the stock market and global temperature in the past. The main thing is, does this model so constructed also predict the future? If it doesn't, the scientist can choose to tweak the model or throw it away. If it does however, there may be a relationship after all that deserves closer examination. When empirical data consistently follows the models, a person that understands real science as opposed to scientism would not dismiss something just because it seems preposterous according to "what is known".
In other words, I think you can be more than 99% sure that the models are empirical, because actually all scientific models are. This is all the more reason why we must be wary of them.
I disagree that all scientific models are empirical. Perhaps you are misunderstanding what I mean by an empirical model as opposed to a model based on first principals.
Models that are based on first principals would use known and proven laws of physics and thermodynamics to predict the future, this often involves an iterative process and usually requires considerably computing power. In a system as complex and large scale as global climate, sucessfully developing a model in this way would be incomprehendably difficult since there are so many factors involved and so many different positive and negative feedbacks. It would also require incomprehendable computing power. Unlike empirical models, these models do not use the output parameters (temperature or CO2 concentration) as an input to the model and for that reason are fundamentally better though as I mentioned earlier, they are much more difficult to produce.
The other type of model is the empirical model. These models do not use established laws of physics and are merely an extrapolation of an existing trend. These models take the measured inputs (temperature & CO2 conc) and fits an equation to this data, the equation will contain hundreds of "fudge factors" in order to produce an equation that fits the input data. The problem is that the model uses the very same input data as the data that is later used to varify the output. For this reason, empirical models should be used with caution. Empirical models may still be useful in certain applications but they are a tool for interpolating simple systems where the relationship between the variables is obvious, they are not a tool for proving that a relationship between two variables exists, especially for unknown and complex systems.
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Alastair Posted 8:06 pm
08 Jun 2007
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Alastair Posted 10:01 pm
18 Jun 2007
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tedsmith Posted 3:40 am
23 Jun 2007
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barry schwarz Posted 2:12 pm
16 Jun 2008
No. The premise for AGW theory is not derived from ice cores. The empirical basis is the fact that increasing CO2 in a volume of atmosphere prevents more radiation from passing through the volume. The hypothesis was put forward over a century ago and validated by lab tests ever since. The premise for AGW theory is physics, not geological records.
you admit that you are wrong, and then you make yet another assertion about how important CO2 is. Why? Where's the research? One minute you tell me its driven by CO2, then you admit that no, it's not.
This argument pops up in various forms throughout the thread.
There is no inconsistency in saying that historically CO2 increases have followed a rise in temperature, and to posit that today, increased CO2 in the atmosphere will raise the global temperature.
Onnu is a tribesman. He knows that every year the river swells when the snow in the mountains begins to melt, and that the river will run almost dry as winter approaches. It's been happening forever. One year a hydroelectric company builds a dam way upstream. Onnu notices that the river doesn't swell this year, and he assumes that summer is late. A neighbouring tribesman tells him of a giant construction that is blocking the water, but Onnu laughs at him. Men could never affect something as powerful as a river. It is just that the snow hasn't melted yet. The river has always changed with the seasons, therefore it always will.
CO2 rises have historically followed temperature rises. No one argues otherwise. Today we have a (relatively) sudden increase in CO2 levels. If CO2 has historically lagged temperature rise by 800 years, where is the extreme and consistent warming event of 800 years that preceded it? There is none. There are small peaks and troughs in temperature over the last thousand years, nothing of the magnitude the fossil evidence recommends we should have experienced to account for the recent CO2 rise. We know it is coming from industry. So the question we ask is "what effect will this atmospheric change have?"
This is the question that spurred AGW theory over a hundred years ago. The fossil record helps us to understand the correlation between GHGs and temperature, but is not the source of AGW theory. Nor does the fossil record undo AGW theory. There is simply no requirement that what happened naturally before must necessarily be what is happening now. Onnu would disagree, but he's not traveled far outside his village.
I really like this analogy from a post at realclimate:
A year ago my car wouldn't start. I had a flat battery. Today my car wouldn't start. The battery tests fine and everything indicates that a faulty starter motor is the problem.
Using the logic in some posts above, I would assume that my battery is flat.
Best scientific estimates reckon that the temperature changes during deglaciation is half accounted for by the Milankovitch cycle - the rest is attributed to GHGs that accumulated in the atmosphere, amplifying the warming. We currently have more CO2 in the atmosphere than we've had in deglaciation periods for millions of years.
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barry schwarz Posted 2:21 pm
16 Jun 2008
Logarithmic.
http://www.realclimate.org/index.php/archives/2007/06/a-s ...
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barry schwarz Posted 3:40 pm
16 Jun 2008
I put that too absolutely. There is little doubt that current atmospheric CO2 concentrations have not been matched for the last 800 000 years (about 10 ice ages/interglacials in the period), and this is likely also the case for the past 20 million years.
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Noise Posted 4:35 am
19 Jul 2008
Going back to the fundamentals, burning oil releases heat & CO2. The CO2 released gets discussed ad nauseum, but rarely do I see a spirited conversation about what happens to the HEAT released by burning oil.
I also find a lot of climate models wilfully neglect to remember that oil & coal will run out within decades. And use the sentence "if we keep using oil/coal/etc at this rate".
Anyone know how much heat energy would be released annually by our current usage? VS net effect on our environment temperature.
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Paleocon Posted 3:59 pm
17 Sep 2008
Try buying a car in the UK where CO2 emissions will determine the cost of the car.
Wouldn't this all be downright evil if we knew that CO2 really wasn't a problem?
I have never been one for burning witches, but by God there ought to be prison sentences for "Crimes against humanity" if this whole CO2 thing turns out to be bogus.
"...a 90 percent chance that the US has contributed .2 degrees F of temperature increase in the last 50 years..." The IPCC Consensus in perspective
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