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Miriam O'Brien (Sou) at 14:39 PM on 8 January 2011What's in a Name?
@ Ron Crouch and Ville - Ron, like, Anne-Marie, I obviously misinterpreted your post. My apologies. Ville - yes, it was a probably poor attempt at sarcasm or maybe satire. IMO humans are as much a part of nature as any other part of nature. We are forcing extremely rapid climate change to the severe detriment of ourselves and all other plant and animal species on earth. Deniers often say that climate change is natural (true) and that therefore humans cannot change the climate (false) - it's like a red rag to a bull for me. -
Miriam O'Brien (Sou) at 14:31 PM on 8 January 2011Zvon.org guide to RealClimate.org
How wonderful. Congratulations and many, many thanks. Your work on this and the IPCC reports is invaluable. -
Ron Crouch at 14:13 PM on 8 January 2011What's in a Name?
If I might be permitted. I just want to express to those of you who do not know me that if there is anyone on the face of this planet who has absolutely no doubt that humans are affecting the climate, it is me. In fact it is my own personal belief that James Lovelock's vision of the future is optimistic. That's how little faith I have in humanity waking up and smelling the roses in time to save their precious butts.Moderator Response: [Daniel Bailey] I have gone over your comments posted since May and I believe you. The more I read on new studies coming out leads me to reluctantly conclude Lovelock may well be right. -
Marcus at 14:12 PM on 8 January 2011Graphs from the Zombie Wars
Ken Lambert, between 1750 & 1950, there was only a 20ppm increase in CO2 concentrations. Since 1950, there has been an 80ppm increase in CO2 concentrations. So really, the important part is how much temperatures have risen since 1950, not 1750 (when the CO2 effect was being masked by the negative forcing of aerosols). Since 1950, we've seen a +0.6 degree increase in *global* temperatures-so what impact do you reckon *another* 80ppm rise in CO2 will do over the next 60 years alone? Of course, that's *before* we consider the reduced albedo effects from melting ice & glaciers-which is a positive feedback-or the impact of clouds, or the impacts of methane release from clathrates. Also remember that this represents an *average* warming only-some parts of the world will warm much more than others-enough to make them effectively uninhabitable. Are you going to tell refugees from these parts of the world (Asia, the Middle East & Sub-Saharan Africa come to mind) that a "mere" 0.8 degree warming is "nothing to be scared of"? Still, got to give kudos for squeezing so many Zombie memes into a single post. -
Ron Crouch at 13:38 PM on 8 January 2011What's in a Name?
#23 sout Don't understand how you get such inference from that. Don't read into things things that are not there. If your going to discuss these issues then spell it out in black and white so that readers who might be less informed than yourself can't possibly construe your comments to mean anything else other than that which is expressed. If terms are interchangeable in casual conversation that's all fine and dandy, but here science is being presented and therefore it is imperative that the correct terminology be used in order to properly educate the uninformed. -
Ron Crouch at 13:19 PM on 8 January 2011What's in a Name?
#24 Anne-Marie That's not what I'm saying. The term global warming on it's own does not infer the requirement that an anthropogenic component be present, global warming can occur totally independent of a human finger print. I'm not disputing that what we are experiencing is Anthropogenically Exacerbated Global Warming. So basically I'm saying that the proper useage of terms is relevant to a particular discussion in order to allay any perceived confusion for the uninformed. -
Phila at 10:55 AM on 8 January 2011Understanding the CO2 lag in past climate change
gallopingcamel, Please be warned that the above link uses many words that may offend you. Offensive? Not really. Irrelevant would be more like it. I grant that there's an intent to upset people, but honestly, that kind of rhetoric stopped being offensive after the first 500,000 instances, and is now mostly just a boring inevitability. Most of us have long since learned to tune this chatter out, and proceed directly to the substance (if any). Frankly, your avoidance of clearly stated, pertinent objections to your "method" (#135 being a recent example) is a lot more irksome than anything in Rutan's approach. For a different view of carbon dioxide in the atmosphere I recommend that you check out the following: Different? Seriously? Do you really imagine that Rutan's arguments are new to anyone who's been paying the slightest attention? Some of the "skeptics" here remind me of a film I once saw of a man with Korsakov's syndrome, who treated each daily visit from his wife as an unexpected miracle. Nevertheless, it is very naughty to suppress zeros on graphs so that weak trends are made to look really scary. Now that actually is offensive. I hope you can back up this accusation. If you can't, I hope you find it within yourself to apologize. If you don't, I hope you go away. If you won't, I hope you're banned. -
Alec Cowan at 09:40 AM on 8 January 2011Understanding the CO2 lag in past climate change
@gallopingcamel It looks like your are programmed to do it again and again. Again you hang an unacceptable comment, get it deleted and comment what you supposedly said there -the part you see fit, the way you see favours you-. This time you chose to continue to misrepresent the figure presented by Daniel Bailey and Daniel himself with a slightly tuned down version of the same attack, but, what happened with the argument? You just have nothing to say. That's the technique: things going wrong, verbal tantrum thrown, comment deleted, you citing the comment deleted, and the argument? Oh! where is it, yeah ... we were talking of what is beyond the stars. Even more, you are making it look like you were debating that with me!!! I hope moderators will understand that it is you who are choosing the comments to be deleted and the time, so they'll find OK to keep them and everybody will follow your real arguments -or lack thereof-. With me you have an issue about highly adjetivated correlations and conclusions you extract from variables you fail to define. I pass the last link you provided. About the previous one, again, what is in the Y-axis? -
Understanding the CO2 lag in past climate change
gallopingcamel - What a curious presentation. Bad unlabeled graphs ending in 1950 on a page labeled "2001", CO2 is not a pollutant, CO2 is miniscule, CO2 is saturated, CO2 is not the only driver of climate, CO2 was higher in the past, preferring stomata measurements to ice cores, CO2 lags temperature.... I could go on, but that's just a selection of evident skeptical fallacies in the first 30 pages of a 100 page PowerPoint. I'm saddened that such a good engineer is putting out junk like this. Of course, I wouldn't go to an engineer for dentistry, or a climate scientist for airframe design. I think that presentation was either a prime example of the Dunning-Kruger effect or an ideology driven ax-grind. You do yourself no favors by presenting this as an alternative to actual science. -
muoncounter at 08:59 AM on 8 January 2011Understanding the CO2 lag in past climate change
#138: "For a different view of carbon dioxide in the atmosphere" To keep it fair and balanced, here's a point-by-point analysis of Rutan's paper. I don't know who the author of that blog is, but I like his style ("promoting democracy one pint at a time"). -
gallopingcamel at 08:32 AM on 8 January 2011Understanding the CO2 lag in past climate change
Alec Cowan (@135), Apparently the moderator agrees with you as #133 is now a comment by "les". Nevertheless, it is very naughty to suppress zeros on graphs so that weak trends are made to look really scary. For a different view of carbon dioxide in the atmosphere I recommend that you check out the following: http://rps3.com/Pages/Burt_Rutan_on_Climate_Change.htm Please be warned that the above link uses many words that may offend you. -
Alec Cowan at 08:19 AM on 8 January 2011Understanding the CO2 lag in past climate change
@gallopingcamel #134 It's obvious you don't understand what's in the Y-axis [PLEASE everybody else: don't explain it to him!], therefore the implications of thatcorrelation: We will follow this but now I will let you explain the variables and implications. Take a while to think it carefully and be sure of not being saying something in the lines "the atmosphere of the planet is one therefore Greenland rules (or any other place that share the same atmosphere)". -
gallopingcamel at 08:12 AM on 8 January 2011Understanding the CO2 lag in past climate change
Daniel Bailey, Thanks for that link in your response to my #132. That plot for high latitudes in Canada looks remarkably similar to my Greenland plot with a long decline starting in 1934. The problem with Ned's plot is that it uses GHCN data which includes a declining number of stations after 1975. There are several years with only two stations (Alert and Resolute). I am working with Enviro Canada data which has at least 15 stations to WMO standards in most of the relevant years. Will it make a difference to include more stations? Ned says "NO" but I need to check that claim for myself.Moderator Response: [Daniel Bailey] In all honesty, that was muoncounter's doing. -
Alec Cowan at 08:06 AM on 8 January 2011Understanding the CO2 lag in past climate change
@gallopingcamel #133 Your assertion of dishonesty ("Your chart showing the CO2 concentration with the suppressed zero is dishonest to say the least.") is the evidence of your lack of instruction in science and ill faith. At least make yourself sure that there's a complete lack of values on an axis next time you try to label as dishonest someone that uses fair graphics but doesn't play along with your prose. You simply are showing here that you understand little science (even little high-school math) and you only have your abilities as polemicist, as you "forgot" to check that the axis had clear values (to say in a civil way that you didn't care or know, and seeing the opportunity of aiming the jugular you took your chance). -
Bibliovermis at 07:57 AM on 8 January 2011It's Pacific Decadal Oscillation
Yes, to posit otherwise requires explaining why the current understanding coincidently adds up. Please read argument #2. -
gallopingcamel at 07:53 AM on 8 January 2011Understanding the CO2 lag in past climate change
Alec Cowan (@119), The correlations I was talking about are really striking. You seem to doubt me so take a look at this: http://www.gisp2.sr.unh.edu/DATA/Bender.html I hope you will agree that a correlation between high latitudes in both hemispheres goes a long way to counter the argument that what goes on in Greenland can be dismissed as a local phenomenon. -
les at 07:40 AM on 8 January 2011Understanding the CO2 lag in past climate change
oh! #125 apiratelooksat50 seemed about to back up his monkying about with this 15% as I asked him to do some posts back... ... imagine my disappointment ;( -
les at 07:37 AM on 8 January 2011Ice age predicted in the 70s
24 snowhare Volcanic triggering of glaciation says "AN instantaneous glaciation model for the formation of the large Pleistocene ice sheets..." so maybe the poodle has a case? The abstract then says... "I suggest here that such a survival could have resulted from one or several closely spaced massive volcanic ash eruptions." or maybe the poodle is being highly selective in his interpretation of the relevance of this. People really shouldn't go round destroying their own credibility that way, especially when they've spent that much time building it up. -
cruzn246 at 07:29 AM on 8 January 2011It's Pacific Decadal Oscillation
PDO as an oscillation between positive and negative values shows no long term trend, while temperature shows a long term warming trend. When the PDO last switched to a cool phase, global temperatures were about 0.4C cooler than currently. The long term warming trend indicates the total energy in the Earth's climate system is increasing due to an energy imbalance. OK, so the global temp has been flopping around in a 2-3 C range for the last 10K years. Do we have all the reasons for these "energy imbalances"? -
gallopingcamel at 07:26 AM on 8 January 2011Understanding the CO2 lag in past climate change
Anne-Marie Blackburn (@113), It is a valid argument to point out that a particular region such as Greenland can be affected by ocean current oscillations, for example. Such factors could indeed explain the declining temperatures in Greenland over the sixty years following 1934. As mentioned in a response to Daniel Bailey earlier, I plan to continue looking at weather stations in high latitudes (e.g. Canada and Russia) in the belief that warming or cooling is magnified in the polar regions.Moderator Response: [muoncounter] See Twice as much Canada, especially the recent warming rates approaching 0.5deg C/decade. -
Rob Painting at 07:18 AM on 8 January 2011Understanding the CO2 lag in past climate change
Pirate @ 125 & 130 - And, Albatross, the question was innocent and in the interest of learning. I find it hard to accept that you teach environmental science. You should at least have basic understanding of the geological and biological carbon cycles. -
apiratelooksat50 at 07:07 AM on 8 January 2011Understanding the CO2 lag in past climate change
KR, Thanks and I am reviewing the links you sent. My question started in response to sphaerica @118 (i.e. connecting the CO2 levels and the orbital forcing). I first saw the orbital forcings years ago on anti-AGW sites and was surprised to see it here. Very interesting are the different viewpoints on something we all agree is happening. And, Albatross, the question was innocent and in the interest of learning. KR's explanations and links are making me think. -
Understanding the CO2 lag in past climate change
Albatross - A reasonable idea. apiratelooksat50 - please post further items on CO2 attribution on the How do human CO2 emissions compare to natural CO2 emissions page; I will not reply further on this thread, as it's rather off-topic to the lead/lag discussion.Moderator Response: Concur. -
Albatross at 06:33 AM on 8 January 2011Understanding the CO2 lag in past climate change
I strongly suspected that apiratelooksat50's question was a set up, made under the guise of curiosity and innocence of course. And subsequent dialogue has shown that to be the case. KR, you have the patience of a saint. Maybe it is time to take this (distracting) discussion to the appropriate thread? Maybe this one, or this one? -
Understanding the CO2 lag in past climate change
apiratelooksat50 - There's additional information on our responsibility for CO2 levels in Comparing CO2 emissions to CO2 levels. -
Understanding the CO2 lag in past climate change
apiratelooksat50 - We put out 29-30B tons of CO2 per year. That would (if not absorbed elsewhere) cause a 4ppm/year increase. We're seeing 2ppm/year rates. And isotopic analysis indicates that it's coming from us. Now, if we weren't putting sufficient CO2 for 4ppm into the atmosphere, would CO2 concentration be increasing by 2ppm? No. It would instead be decreasing as the abnormally high (390 instead of 285) CO2 got absorbed by the oceans and biosphere. As I said before, basic math - we are 100% responsible for the 2ppm/year increase. We're putting up an excess that cannot be fully reabsorbed in the normal carbon cycle or carbon sinks, and we are responsible for that excess. In fact we are responsible for both the atmospheric increase and the changes in ocean acidification - we pump out twice as much as stays up in increased atmospheric CO2. -
apiratelooksat50 at 06:10 AM on 8 January 2011Understanding the CO2 lag in past climate change
KR@123 But, we are not 100% responsible for the 2ppm rise per year. So, the calculations need to be adjusted. According to US DOE approximately 15% of annual emissions are anthropogenic. Regardless of how we monkey around with the numbers of what is staying in the atmosphere and not being sequestered in carbon sinks, we are not responsible for the full amount of the increase. Peace! -
Understanding the CO2 lag in past climate change
apiratelooksat50 - In regards to the 285ppm value Sphaerica mentioned, that's the CO2 value reached in the normal (and uninfluenced by industrial emissions) climate cycle, the slow glacial cycle of the last half million years. By all indications we should be on a slow decline in temperatures, with slowly decreasing CO2 values, heading into an ice age about 10,000 years from now. Of course, that's unlikely to happen now... -
Understanding the CO2 lag in past climate change
apiratelooksat50 - How did we pump it up? By burning lots of carbon based fuels, currently increasing atmospheric carbon by 2ppm/year, as shown by isotope analysis and basic math. The 2ppm represent 15B tons of emissions - we pump out 30B tons, so roughly half of what we put out is currently being sequestered (see Ocean acidification for where some of it is going). How do you arrive at the 285ppm figure? That's the pre-industrial value for CO2, roughly the peak value seen in the last 400K years (Figure 1). We're currently at 35% higher CO2 levels than seen in hundreds of thousands of years, while other forcings (orbital inclinations, solar levels) have not changed. It's getting warming, we did it, no great surprises here. -
apiratelooksat50 at 05:41 AM on 8 January 2011Understanding the CO2 lag in past climate change
Dhogaza@121 People like you are why it is difficult to have any civil discourse. Of course we burn fossil fuels that put CO2 into the atmosphere. Did I even imply otherwise? I'm intellectually interested in how sphaerica derived those numbers. -
dhogaza at 05:35 AM on 8 January 2011Understanding the CO2 lag in past climate change
"Respectfully, how did we artificially "crank up" the CO2 level to 390 ppm from a 285 ppm normal?" You don't believe that burning carbon-based fuels results in CO2 being poured into the atmosphere? Or do you think some sort of magic wand is sweeping all of that CO2 out of the atmosphere? -
Ned at 05:26 AM on 8 January 2011Ice age predicted in the 70s
My favorite early paper on climate change is Wally Broecker's 1975 paper in the journal Science: Broecker, W. 1975. Climatic change: are we on the brink of a pronounced global warming? Science, 189-460-463. It's discussed in some detail at RealClimate ("Happy 35th birthday, global warming!"). Kind of neat that even back in 1975, Wally B. was using both "climat[ic] change" and "global warming" more or less interchangeably ... even in the very title of this paper. Also, amazingly prescient of Wally, considering that 1975 is more or less when global temperatures came out of a lull and began rising steadily. -
apiratelooksat50 at 05:21 AM on 8 January 2011Understanding the CO2 lag in past climate change
118 Sphaerica, "In today's case, the temperature-stable CO2 level is still 285 ppm, even though we've cranked it up to 390 ppm. 285 ppm is the level that the planet wants to hold CO2 to right now, based on the current mean global temp. We have artificially pumped that up to 390 ppm, not by changing the planet's temperature (the "natural" way) but rather by injecting the CO2 into the atmosphere." Respectfully, how did we artificially "crank up" the CO2 level to 390 ppm from a 285 ppm normal? And, how do you arrive at the 285 ppm figure? -
muoncounter at 04:58 AM on 8 January 2011We're heading into cooling
#15: "it lined up with the NAO/PDO cycles" Every time we go off topic on one of these NAO/PDO tangents, I have to wonder how an oscillation can give rise to a long period increasing trend. But that topic belongs to this thread. -
Mila at 04:35 AM on 8 January 2011Zvon.org guide to RealClimate.org
Thanks :) #1 my work includes a lot of ad hoc programming and manual work (my background in organic chemistry helps, if for almost 10 years you spend a few hours a day washing glassware you are prepared for some tedious work :) ) I am not aware of any software which would fulfill your needs, but I would expect that some exist. But be cautious before purchase, it means to correctly read in PDF files and identify important bits (and this is far from trivial - you may see at Google Scholar that even for them it is not always easy), then to assign dois, as soon as you have PDF - dois mapping the rest is not so difficult -
Yvan Dutil at 04:32 AM on 8 January 2011Graphs from the Zombie Wars
#54 @caerbannog For those who think that the CO2-lags-temperature argument is a valid argument against global-warming theory, here's a question: Why was the Earth so warm then? (Now remember that solar + land-albedo forcing was the same or a bit less then than it is now). Well, it comes that CO2 concentration was much higher then than now. http://www.sciencemag.org/content/330/6005/819.abstract This as been discussed here before: http://www.skepticalscience.com/Climate-change-from-40-million-years-ago-shows-climate-sensitivity-to-CO2.html -
mmiller at 04:24 AM on 8 January 2011The Scientific Guide to Global Warming Skepticism
As evangelical Christian, I would like to thank you for this site and this guide. I have too many friends who are anti science and think global warming is a left wing conspiracy. -
Anne-Marie Blackburn at 03:27 AM on 8 January 2011Zvon.org guide to RealClimate.org
Another phenomenal resource, so again thank you for this, Mila. -
Albatross at 03:21 AM on 8 January 2011Zvon.org guide to RealClimate.org
Wow Mila, you continue to impress. If one is willing to create the database of PDFs of journal papers, could one use your code to create a searchable database? I think researchers would clammer to purchase a software package that would help generate such a database (by ripping though folder containing hundreds of PDFs) and then creating an interactive search engine. I have thousands of papers in my PDF library, but finding the right paper can be tedious and time consuming. Maybe something like that already exists, in which case I'd be delighted if someone could point me in the right direction. Thanks. -
cruzn246 at 03:09 AM on 8 January 2011We're heading into cooling
There are all kinds of cycles Bib. We have been in some multi decadal cycles over the past 30/60 years that we still do not fully understand. It seems the PDO NAO tandem may be driving this shorter term cycle we are in. There are more than a few scientists who see this multi decadel cycle as real. I know I saw some kind of 30/60 year cycle in my tornado data for Alabama. It sure looked like it lined up with the NAO/PDO cycles to me. Response: [Daniel Bailey] Then prove it: do the analysis, write it up, publish it. I plan to as a grad student. -
cruzn246 at 02:54 AM on 8 January 2011We're heading into cooling
Are you studying it Bib? -
cruzn246 at 02:53 AM on 8 January 2011We're heading into cooling
There are all kinds of cycles Bib. We have been in some multi decadal cycles over the past 30/60 years that we still do not fully understand. It seems the PDO NAO tandem may be driving this shorter term cycle we are in. There are more than a few scientists who see this multi decadel cycle as real. I know I saw some kind of 30/60 year cycle in my tornado data for Alabama. It sure looked like it lined up with the NAO/PDO cycles to me.Moderator Response: [Daniel Bailey] Then prove it: do the analysis, write it up, publish it. -
Bibliovermis at 02:53 AM on 8 January 2011We're heading into cooling
When discussing the global climate, it helps to study the "whole world". -
Alec Cowan at 02:46 AM on 8 January 2011Understanding the CO2 lag in past climate change
@gallopingcamel #116 There's a buzzword "correlation" and there's a statistical concept. For instance, you have to calculate a correlation for two variables and you get a number that has usually attached adjectives -like 'good'- in intervals set by uniform criteria. In your sentence "While this is a relatively small region, there is a good correlation between the GISP/GRIP results and Vostok in Antarctica" declares an adjectival correlation for two names, something that doesn't exist. Could you state your variables and the value of such correlation? Either you did the calculations yourself or you get the values elsewhere, so you should have no problem in answering that. Other choices are you got it as a verbal chain elsewhere and are repeating it without really knowing -the bad use of concepts may be a hint- or you might be making that up. I don't think the last choices are possible, but in the lack of a precise answer, what one should think? -
Bibliovermis at 02:45 AM on 8 January 2011We're heading into cooling
Cool weather in your area does not cancel out global warming. I suspect in 10 years you'll still be saying "global cooling is going to start now" because it snowed somewhere during winter. There is no 60 year temperature cycle. This persistent "skeptic argument" needs its own article. -
cruzn246 at 02:45 AM on 8 January 2011We're heading into cooling
Murph, I am studying climatology. I just finished a paper on the climatology of Tornadoes in Alabama over the past 60 years. I am not a graduate student so it was not up for peer review. It was my senior project though, and no scientific error was found by my professors. I have to admit that I do not seriously study the "whole world" thing yet, because quite frankly it's about way too complicated, but I know that many of the "it's never been" stuff we are seeing now is pure baloney. BTW, my study showed that we have been in a down period for tornadoes over Alabama. Activity peaked in that area in the mid 70s and declined from that point on till the mid 90s. It is now on the upswing and is back to where it was in the early 50s. Using ten year averaging I made a graph that almost looks like a sine wave that shows the trend. A colleague did Georgia and found the same thing.Moderator Response:[Daniel Bailey]
"I have to admit that I do not seriously study the "whole world" thing yet, because quite frankly it's about way too complicated, but I know that many of the "it's never been" stuff we are seeing now is pure baloney."
Welcome to the field. If you want to get a degree in climatology you should spend more time learning the hard stuff and less time hand-waving.
-
kdfv at 02:37 AM on 8 January 2011It's freaking cold!
#68 jmurphy the second map is http://climvis.ncdc.noaa.gov/cgi-bin/cag3/state-map-display.plModerator Response: [Daniel Bailey] Your URL link is broken. -
cruzn246 at 02:32 AM on 8 January 2011We're heading into cooling
Well, we are going through our coldest winter in a heck of a long time in the Midwest. Why not pop up? Sorry about the EPO typo, you all knew I meant the PDO. Don't know what I was thinking. 2010 was one of the warmest? Big deal. 1977 was one of the coldest and it was during the beginning of last warm-up period. You get some contradictory times on the edge of periods. We are in a cooling period. you'll all admit it on about ten years.Moderator Response:[Daniel Bailey] Wrong:
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keithpickering at 02:24 AM on 8 January 2011Graphs from the Zombie Wars
#63 MarkR: You're right, no physical reason, and the polynomial fit isn't enough better than linear to be worth talking about at all -- except that it shows that the apparent flatness is illusory. #64 Ken Lambert: "However assuming that you CO2 component only curves are worth talking about, the temperature anomaly is tracking somewhere between 1.2 and 1.8degC for a doubling of CO2." That number is derived from radiative physics only, so it excludes all feedbacks. The rough estimate from linear regression above includes short-term feedbacks (at least), e.g., water vapor. Which accounts for the difference. -
Bob Lacatena at 02:05 AM on 8 January 2011Understanding the CO2 lag in past climate change
108, lurgee, 109, Albatross, 110, Daniel Bailey I believe the main reason that CO2 levels stay high for thousands of years is that the two scenarios are very different. In today's case, the temperature-stable CO2 level is still 285 ppm, even though we've cranked it up to 390 ppm. 285 ppm is the level that the planet wants to hold CO2 to right now, based on the current mean global temp. We have artificially pumped that up to 390 ppm, not by changing the planet's temperature (the "natural" way) but rather by injecting the CO2 into the atmosphere. But if we abruptly stopped, it would start to fall immediately because the temperature of the planet hasn't caught up. It might take a few hundred years to get down, partly because in the interim the planet would warm, raising that "natural level" above 285 ppm, but it would still fall a lot faster. In the interglacial period case, where levels start at 285 ppm and fall to 190 ppm over thousands of years, it is a very slow cooling/feedback response where the temperature-stable level is slowly reduced. That is, the temperature of the planet is slowly reduced, which reduces the equilibrium CO2 level, which further reduces the temperature. The change in orbital forcing allows winter snow/ice in the northern hemisphere to expand (or, rather, fail to melt all the way back in summer, increasing the extent bit by bit each year). The resulting change in albedo reflects more sunlight, cooling the planet very slightly. As the oceans cool, they absorb more CO2, which cools the planet further, while atmospheric H2O content also drops, cooling things even more. This whole process is very, very slow, taking thousands of years. So in our case, you have a system that has been thrown out of balance/equilibrium, and so will fall back into balance/equilibrium relatively quickly. In the interglacial-to-glacial case (or the opposite, the exiting of a glacial period), you have a very slow acting forcing/feedback response which is changing the equilibrium level itself, bit by bit, and the planet slowly adjusts. They are two completely different cases, and diametrically opposed mechanisms (changing temperatures by abruptly changing CO2 levels, versus changing CO2 levels and temperatures by slowly changing temperatures). And it's all related to the whole CO2-lags-temperature argument. It's in understanding the system as a whole that it makes sense, and moving beyond the overly simplistic CO2-is-a-magic-wand-that-does-this-one-exact-thing approach.
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