The question of “which comes first, the temperature or the CO2 rise?” has been much like the proverbial “which came first, the chicken or the egg?” question. This seems to settle it – temperature came first, followed by an increase in CO2 outgassing from the ocean surrounding Antarctica.
“Our analyses of ice cores from the ice sheet in Antarctica shows that the concentration of CO2 in the atmosphere follows the rise in Antarctic temperatures very closely and is staggered by a few hundred years at most,” – Sune Olander Rasmussen
From the University of Copenhagen – Rise in temperatures and CO2 follow each other closely in climate change
The greatest climate change the world has seen in the last 100,000 years was the transition from the ice age to the warm interglacial period. New research from the Niels Bohr Institute at the University of Copenhagen indicates that, contrary to previous opinion, the rise in temperature and the rise in the atmospheric CO2 follow each other closely in terms of time. The results have been published in the scientific journal, Climate of the Past.
In the warmer climate the atmospheric content of CO2 is naturally higher. The gas CO2 (carbon dioxide) is a green-house gas that absorbs heat radiation from the Earth and thus keeps the Earth warm. In the shift between ice ages and interglacial periods the atmospheric content of CO2 helps to intensify the natural climate variations.
It had previously been thought that as the temperature began to rise at the end of the ice age approximately 19,000 years ago, an increase in the amount of CO2 in the atmosphere followed with a delay of up to 1,000 years.
“Our analyses of ice cores from the ice sheet in Antarctica shows that the concentration of CO2 in the atmosphere follows the rise in Antarctic temperatures very closely and is staggered by a few hundred years at most,” explains Sune Olander Rasmussen, Associate Professor and centre coordinator at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.
Law Dome in Antarctica.
Deep-sea’s important role
The research, which was carried out in collaboration with researchers from the University of Tasmania in Australia, is based on measurements of ice cores from five boreholes through the ice sheet in Antarctica. The ice sheet is formed by snow that doesn’t melt, but remains year after year and is gradually compressed into kilometers thick ice. During the compression, air is trapped between the snowflakes and as a result the ice contains tiny samples of ancient atmospheres. The composition of the ice also shows what the temperature was when the snow fell, so the ice is an archive of past climate and atmospheric composition.
“The ice cores show a nearly synchronous relationship between the temperature in Antarctica and the atmospheric content of CO2, and this suggests that it is the processes in the deep-sea around Antarctica that play an important role in the CO2 increase,” explains Sune Olander Rasmussen.
He explains that one of the theories is that when Antarctica warms up, there will be stronger winds over the Southern Ocean and the winds pump more water up from the deep bottom layers in the ocean where there is a high content of CO2 from all of the small organisms that die and fall down to the sea floor and rot. When strong winds blow over the Southern Ocean, the ocean circulation brings more of the CO2-rich bottom water up to the surface and a portion of this CO2 is released into the atmosphere. This process links temperature and CO2 together and the new results suggest that the linking is closer and happens faster than previously believed.
Climatic impact
The global temperature changed naturally because of the changing solar radiation caused by variations in the Earth’s orbit around the Sun, the Earth’s tilt and the orientation of the Earth’s axis. These are called the Milankowitch cycles and occur in periods of approximately 100,000, 42,000, and 22,000 years. These are the cycles that cause the Earth’s climate to shift between long ice ages of approximately 100,000 years and warm interglacial periods, typically 10,000 – 15,000 years. The natural warming of the climate was intensified by the increased amount of CO2 in the atmosphere.
“What we are observing in the present day is the mankind has caused the CO2 content in the atmosphere to rise as much in just 150 years as it rose over 8,000 years during the transition from the last ice age to the current interglacial period and that can bring the Earth’s climate out of balance,” explains Sune Olander Rasmussen adding “That is why it is even more important that we have a good grip on which processes caused the climate of the past to change, because the same processes may operate in addition to the anthropogenic changes we see today. In this way the climate of the past helps us to understand how the various parts of the climate systems interact and what we can expect in the future.”
Tightened constraints on the time-lag between Antarctic temperature and CO2 during the last deglaciation
J. B. Pedro1,2, S. O. Rasmussen3, and T. D. van Ommen2,4
1Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tasmania, Australia
2Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
3Centre for Ice and Climate, University of Copenhagen, Copenhagen, Denmark
4Australian Antarctic Division, Kingston, Tasmania, Australia
Abstract. Antarctic ice cores provide clear evidence of a close coupling between variations in Antarctic temperature and the atmospheric concentration of CO2 during the glacial/interglacial cycles of at least the past 800-thousand years. Precise information on the relative timing of the temperature and CO2 changes can assist in refining our understanding of the physical processes involved in this coupling. Here, we focus on the last deglaciation, 19 000 to 11 000 yr before present, during which CO2 concentrations increased by ~80 parts per million by volume and Antarctic temperature increased by ~10 °C. Utilising a recently developed proxy for regional Antarctic temperature, derived from five near-coastal ice cores and two ice core CO2 records with high dating precision, we show that the increase in CO2 likely lagged the increase in regional Antarctic temperature by less than 400 yr and that even a short lead of CO2 over temperature cannot be excluded. This result, consistent for both CO2 records, implies a faster coupling between temperature and CO2 than previous estimates, which had permitted up to millennial-scale lags.
Final Revised Paper (PDF, 463 KB) Discussion Paper (CPD)
Citation: Pedro, J. B., Rasmussen, S. O., and van Ommen, T. D.: Tightened constraints on the time-lag between Antarctic temperature and CO2 during the last deglaciation, Clim. Past, 8, 1213-1221, doi:10.5194/cp-8-1213-2012, 2012.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Smokey says:
July 24, 2012 at 2:01 pm
Entropic says:
“In the last 100 years CO2 has risen again, by 110ppm from 280ppm to 390ppm. The last time CO2 changed this much it accompanied a 5C temperature rise.”
“Did you read the article? Or even the headline? Rises in CO2 follow rises in temperature, on time scales from months to hundreds of millennia. And most of the effect of CO2 has already occurred, as you can see here.
Explain why temperature is no longer rising along with CO2. Seems to be a disconnect in the CO2=AGW conjecture, no?”
You are conflating two different events.
20,000 years ago a rise in temperature due to orbital changes led to a rise in temperature, then a rise in CO2, fopllowed by a complex positive feedback interaction between the two.
In the 19th century an ongoing increase in CO2 began. In the 20th century an increase in temperature followed. Of the possible causes for the temperature change investigated, increased back radiation due to increased CO2 is the hypothesis which best fits the data, with a possible resumption of the positive feedback interaction to come.
Since it may be a long time before a new equilibrium is reached, I would reserve judgement on the “no temperature rise ” argument until we have a longer baseline than 12 years.
>>
Entropic man says:
July 24, 2012 at 1:40 pm
Sorry about that. The link was to another post on this website. Perhaps you should refer your complaint to the webmaster.
<<
No. I have no complaints about my treatment here. It’s just that your reference to the other thread doesn’t make the point you seem to be trying to make.
I happen to agree with Chris Wright: “it’s almost as if the greenhouse effect simply isn’t working in the climate system. I assume it can be demonstrated in a laboratory, but it appears to be impossible to demonstrate in the real world.”
The other thread you referenced is a mishmash of concepts.
Jim
Jim Masterson says:
July 24, 2012 at 3:36 pm
>>
Entropic man says:
July 24, 2012 at 1:40 pm
Sorry about that. The link was to another post on this website. Perhaps you should refer your complaint to the webmaster.
<<
No. I have no complaints about my treatment here. It’s just that your reference to the other thread doesn’t make the point you seem to be trying to make.
I happen to agree with Chris Wright: “it’s almost as if the greenhouse effect simply isn’t working in the climate system. I assume it can be demonstrated in a laboratory, but it appears to be impossible to demonstrate in the real world.”
The other thread you referenced is a mishmash of concepts.
Websites for the Met office, NASA Goddard, the Hadley Centre, the Environment Agency and many others, (even Wikpedia) give clear descriptions of the processes underlying the greenhouse effect. I hesitate to give links here, since the ethos of this site automatically assumes that such sites are, to use a term I saw here today, untrustworthy.
[REPLY: Nice try, but don’t try it again. If you have links, post them. Expect criticism if they really are untrustworthy. Expect argument if the descriptions are shonky. Very little gets snipped here and it has to be pretty egregious. The moderators will let you know if it is. Stay civil, obey site policy, and everything will be fine. Casting aspersions is a cause to be snipped. Please don’t do it again. -REP]
Ok correct me if I’m wrong, but does this paper not confirm that a) temperature rises leading to b) increase in c02 levels. Therefore co2 is not causing the temperature rise (at least is not the driving force behind it) and therefore the only way we can have further “apocalyptic” warming is if there is a yet to be discovered positive feedback that increases the temperature rise.
Peridot says: July 24, 2012 at 8:07 am Help …!
Hope this helps.
______________
My Summary – The “Mainstream” Catastrophic Humanmade Global Warming Debate:
Conventional climate theory, assuming zero feedback, suggests that a doubling of atmospheric CO2 would result in ~1 degree C of global warming.
Warming alarmists say there are positive feedbacks to increasing CO2 (and build this assumption aggressively into their climate models), whereas climate skeptics say there are negative feedbacks.
The skeptics easily win this mainstream debate, because there is no evidence of net positive feedbacks to increased CO2 in the climate system, and ample evidence of negative feedbacks.
Also, despite increased atmospheric CO2, there has been no net global warming in about a decade.
The probability therefore is that “climate sensitivity” to a hypothetical doubling of atmospheric CO2 is significantly less than 1 degree C.
Furthermore, I suspect that a doubling of atmospheric CO2 is unlikely to happen due to human activity – so we can expect much less than 1 degree C of global warming.
The above ASSUMES that one accepts the premises of the mainstream debate.
BUT there is perhaps a bigger problem with the mainstream debate:
Atmospheric CO2 LAGS temperature at all measured time scales, from hundreds of years on a long cycle, to 9 months on a short cycle;
SO
the hypothesis that CO2 is a significant driver of global temperature, core to the mainstream debate, apparently assumes that the future is causing the past.
The popular counterarguments are:
a) The lag of CO2 after temperature is a “feedback effect”,
OR
b) It is clear evidence that time machines really do exist.
Both counterarguments a) and b) are supported by equal amounts of compelling evidence. 🙂
This thorny point may not be resolved in my lifetime, but I’ll just remind you of some of the assumptions that are near and dear to the hearts and “logic” of the global warming alarmists:
1. They apparently assume that the Uniformitarian Principle has been especially exempted for their particular brand of “science”.
2. The also assume that Occam’s Razor can similarly be ignored, apparently again, just for them.
The increasing desperation of the warming alarmists is evidenced by their evermore Byzantine explanations of the observed flat or cooling global temperatures in this century. What is it this week – aerosols, dust, volcanoes. the appalling scarcity of buffalo farts… the list of farfetched apologia is endless and increasingly pathetic.
Earlier, there was Mann-made global warming, the “Divergence Problem” and “Hide the Decline”. The list of global warmist chicanery is increasingly long and unprincipled.
It is notable that not one of the very-scary global warming predictions of the IPCC has materialized. The IPCC has demonstrated negative predictive skill. All its scary predictions have proven false.
__________________
If the above post is too political, try this one:
http://wattsupwiththat.com/2012/04/06/a-reply-shakun-et-al-dr-munchausen-explains-science-by-proxy/#comment-948287
CO2 lags temperature at all measured time scales from ~~600-800 years in the ice core records on a long temperature-time cycle, to 9 months on a much shorter time scale.
http://icecap.us/images/uploads/CO2vsTMacRae.pdf
We really don’t know how much of the recent increase in atmospheric CO2 is natural and how much is manmade – possibilities range from entirely natural (~~600-800 years ago was the Medieval Warm Period) to entirely manmade (the “mass balance argument”). I lean towards mostly natural, but I’m not certain.
Although this questions is scientifically crucial, it is not that critical to the current “social debate” about alleged catastrophic manmade global warming (CAGW), since it is obvious to sensible people that IF CO2 truly drives temperature, it is an insignificant driver (climate sensitivity to CO2 is very low; “feedbacks” are negative) and minor increased warmth and increased atmospheric CO2 are beneficial to both humanity AND the environment.
In summary, the “climate skeptics” are trouncing the warming alarmists in the “mainstream CAGW debate”.
Back to the crucial scientific question – is the current increase in atmospheric CO2 largely natural or manmade?
Please see this 15fps AIRS data animation of global CO2 at
http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003562/carbonDioxideSequence2002_2008_at15fps.mp4
It is difficult to see the impact of humanity in this impressive display of nature’s power.
All I can see is the bountiful impact of Spring, dominated by the Northern Hemisphere with its larger land mass, and some possible ocean sources and sinks.
I’m pretty sure all the data is there to figure this out, and I suspect some already have – perhaps Jan Veizer and colleagues.
THX, it’s not a binary situation, where either x causes y or vice versa. Both can be true in a feedback scenario. This is a point that many people here either can’t compass mentally, or are disinclined to credit (often mistakenly assuming that ‘feedback’ = ‘runaway effect’).
For the last 20 years or so, since we had the technology to examine timings of the temperature and gas/aerosol loadings from ice cores, the story has CONSISTENTLY been that orbital variation is the trigger for temperature changes, which cause GHGs to outgas, which operate as feedbacks to the temperature rise. This has been the understanding for about two decades.
This paper does nothing to change that broad understanding on ice age transitions. Like many studies in the last 20 years, what is being attempted is to get tighter constraints on timings and contributions from various components involved in the transistion process. This paper refers to a recent one, also posted about at WUWT. As usual, there is no conflict with the long-held broad understanding.
http://www.clim-past.net/8/1213/2012/cp-8-1213-2012.pdf
It is somewhat astonishing to me that the perversion of the 20 year-old understanding of ice age transitions has such traction. Reading comments here you could be led to believe that the story has changed, or that this study puts paid to the notion of CO2 contributing to deglaciation events. But it is simply the wishful thinking of the commenters. “CO2 lags not leads!” is a simplistic meme, but obviously an attractive one for decidedly unskeptical thinkers.
For an excellent history of the study of ice age transitions via ice cores (etc), see Spencer Weart’s site. He is an historian of science.
http://www.aip.org/history/climate/cycles.htm
From the History of Climate science page, Weart makes what I think is one of the strongest points regarding atmospheric contribution to glacial transitions:
Understanding the intricacies of timing and contribution is the focus of papers such as the one that is the subject of this thread. But the overall picture is pretty straightforward and has been the same for many years.
Entropic man says:
July 24, 2012 at 6:28 am
….. At the start of our interstadial,20,000 years ago the orbital changes began a temperature rise which then led to an increase in CO2 from 200ppm. The increased CO2 increased the temperature more, leading to a positive feedback cycle which increased both until the system reached a new equilibrium some 5C warmer and with about 280ppm of CO2 after 10,000years. You can see that in graph A above. Smaller effects have bobbed the temperatures up and down a bit around these values for the last 10,000 years.
The concern now is that we have increased the amount of CO2 by at least as much again in the last century, from 280ppm to 390ppm.
If the physics of the greenhouse effect is correct, this is likely to reset the equilibrium temperature higher, though how much higher is under discussion by IPCC, posters here and a lot of others.
___________________________________
I think Mother Nature disproved your scenario in this graph. Take a good hard look at the Eocone and the Holocene on the right. Either the Ice Core CO2 data is incorrect as Dr. Jaworowski and others have stated or your conjecture is flat out wrong. That of course does not stop the ‘true believers’ from trying to come up with ways to promote CO2 from the bit player it is back to ‘Control Knob’ status.
(Graph shows temp from the Vostok and CO2from the Vostok, Law Dome and Mauna Loa.)
Chris Wright says: @ur momisugly July 24, 2012 at 4:05 am
” it’s almost as if the greenhouse effect simply isn’t working in the climate system. I assume it can be demonstrated in a laboratory, but it appears to be impossible to demonstrate in the real world.”
__________________________________
I can think of good reasons for that. I have not seen them discussed here although Sleepalot did bring them up.
First one of the bits of information the Warmists always seem to leave out is that the wavelengths from the sun are higher in energy then the infrared energy from the earth.
The second bit of information is the spread of the wavelengths from the sun vs earthshine: graph
And the third bit is both water, carbon dioxide, methane as well as oxygen and ozone absorb in the solar energy band as well as the earthshine band. This means what ever physics the Warmist claim for Carbon Dioxide’s interaction with the earthshine energy band must also hold true for the solar energy band. graph
Trenbeth in his cartoon shows that solar band atmosphere physics to equate to 67 Wm2 he shows the earthshine as 390 Wm2 and the ‘Back radiation’ physics as 324 Wm2. (note that convection is only 24 Wm2 and latent heat from water change state is only 78Wm2)
Sleepalot looked at temperature and humidity data for a rain forest and a desert. The data indicates that water vapor increases the low temperatures and decreases the high temperatures, effectively smoothing out the daily temperature swings. The diurnal variation is 10C for the high humidity area and 30C for the desert. I looked at sunny days only in the rain forest and found the same. Also when altitude is taken into account the net temperature effect of humidity (and other variables) is to drop the temperature by 8C in the rain forest compared to the desert. link and link So it would seem the water vapor might be blocking a bit more than the 67 Wm2 trenberth is showing.
This graph of the air and ground temperature as recorded during a solar eclipse in the North Africa (desert) shows how fast the earth’s air and surface react to changes in solar energy with no humidity mucking up the works. http://www.shadowchaser.demon.co.uk/eclipse/2006/thermochron.gif
As E.M. Smith said
Spector brings up an interesting point as shown in this graph.
davidmhoffer? also brought up the point that even if the global temperature did increase by 1C it would not be a uniform increase across the earth. And then there is Willis’ Thunderstorm Thermostat Hypothesis that makes a joke out of Trenberth’s measly 24Wm2 for thermals (Think Hadley cell, Ferrel cell, and Polar cell as well as thunderstorms, tornadoes and hurricanes)
OH, and I might add that if Trenberth’s is correct about that measly 24Wm2 for thermals aka wind, then we can completely forget about Wind Power as a commercial source of energy. (Snicker)
The top conversion efficiency is 70% (computed numerical values possible) and only in the 15 to 20 mph window http://k0lee.com/turbineeff.htm
Someone may want to wave that information in front of the nose of the city council when the subject of windfarms comes up.
Entropic man says:
July 24, 2012 at 1:35 pm
mkelly says:
July 24, 2012 at 9:50 am
Entropic man says:
July 24, 2012 at 6:28 am
“How much of the 5 C temperature gain is directly attributable to the 80 ppm increase in CO2 and how much is directly to orbital changes?
Since we are not to 400 ppm yet, CO2 can only account for 1.2 C of any temperature change since the bottom of 200 ppm. We’ve gone up over 5 which includes any gain from CO2 and feed backs. So we are safe.”
“One slight misconception there.”
Don’t think I had a misconception at all, but even if I did you failed to answer the questions. How much of the 5 C is directly attributable to CO2 and how do you know we are not in one of you little “small effects” that is causing the temperarture to be bobbing around?
barry says:
July 24, 2012 at 10:58 pm
THX, it’s not a binary situation, where either x causes y or vice versa. Both can be true in a feedback scenario…. This paper does nothing to change that broad understanding on ice age transitions… This paper refers to a recent one, also posted about at WUWT. As usual, there is no conflict with the long-held broad understanding.
“… Shakun et al. (2012) is also warranted….” and just like this paper Shakun et al. (2012) got debunked too.
A new paper in Nature suggests CO2 leads temperature, but has some serious problems
Shakun, Not Stirred, and Definitely Not Area-Weighted
A reply to Shakun et al – Dr. Munchausen Explains Science By Proxy
Did Shakun et al. really prove that CO2 preceded late glacial warming? [Part 1]
More fatal flaws in the Shakun et al. Nature paper claiming that CO2 preceded late glacial warming [Part 2]
And that is only part of the discussion on the Shakun paper. You can web search for the rest.
As far as “….that the perversion of the 20 year-old understanding of ice age transitions has such traction….” I suggest you read In defense of Milankovitch and follow the links to the peer reviewed paper. (I did not know that 2006 was 20 years ago)
You know, I tend to trust Scandinavian scientists more when it comes to ice, They love the stuff. Norwegians know more about both the Arctic and Antarctic than the rest of the world added together – at least their love of the stuff and their history in exploration makes it sacred ground that they are not going to desecrate by fraudulent manipulation of data. Yeah I know “Copenhagen summit” and all that, but I believe their temp graph of the above 80N lat, and I trust the Norwegian ice extents more than anyone else’s.
@ur momisuglyHow in the hell can Temperature rise and CO2 rise “follow each other closely.” ? That’s got to be just about the stupidest thing I have ever read in what purports to be a “scientific study report.”
Make up your minds; which one is leading and which one is following ?@ur momisugly
@ur momisuglyThey really mean: Pre hoc, ergo propter hoc…
“First the temperature rose, so it was caused by the CO2 that followed.”
That is plain ridiculous.@ur momisugly
Couldn’t they happen practically simultaneously? Shouldn’t we judge the past by the present? Can’t we conduct a laboratory test on how much CO2 is released by sea water for any increment of warming? When sea water is heated CO2 is immediately released.
Gail,
The notion that orbital variations ‘trigger’ ice age transitions is older than two decades, and has underpinned the understanding of ice age dynamics since the 1980s. There’s no need to isolate Milankovitch theory, as it is part and parcel of the suite of processes that cause glacial changes. You seem to be positing opposing viewpoints where there is no opposition.
The objections to Shakun et al and the current paper are based on muddled thinking and misunderstandings. It’s not worth trawling through all the junk there, but let’s take the first objection from the first WUWT article you linked.
Denying the greenhouse effect of CO2? Instantly dismissable. Water vapour accounts for about 66 to 80%, not 95% of the greenhouse effect. Not to mention that atmospheric water vapour content is a feedback process and short-lived in the atmosphere, whereas CO2… well, the memes supporting this first assertion are plentiful.
If rebutting Shakun relies on denying the greenhouse effect of CO2, then it’s useless taking the discussion seriously. Complete waste of time. Accepting that CO2 has an effect (you can include Richard Lindzen, Roger Pielke Jr and Sr, Roy Spencer, John Christie, and any other actual climate scientist amongst those who have no doubt CO2 is a greenhouse gas that shoulod cause some warming if atmospheric content is increased) leads to the understanding that CO2 will amplify warming during the transition from glacial maximum top interglacial. The only poit worth discussing is how much it will contribute. The lead/lag argument is an ideologically driven distraction. CO2 could lag at all times and in all places, but can still amplify the warming effect. And this is the point – not whether CO2 is a greenhouse gas, which is the notion Easterbrook and Essenbach base their arguments on, whether or not they come right out and say it.
And where is the current paper “debunked”? All they’re suggesting is that CO2 began accumulating after Antarctic warming by ~400 years or less, which is a tighter lag than estimated previously (but within confidence bounds of some earlier studies, eg Monnin et al 2001). It changes nothing of the bigger picture, and I can only assume skeptics have taken an interest due to some red-flag phrases or something.
>>
barry says:
July 25, 2012 at 6:33 pm
The lead/lag argument is an ideologically driven distraction. CO2 could lag at all times and in all places, but can still amplify the warming effect.
<<
There’s an old post by Frank Lansner that should have put a stop to this “distraction.” Although alarmists like to blame CO2 with a lag time of hundreds of years as responsible for raising the temperature of the Earth, they completely ignore the temperature/CO2 relationship on the downside. The CO2 on the downside should fall long before the temperature starts to drop, but it doesn’t. It not only stays high (where it should be causing massive warming), but it lingers there longer. Why aren’t we looking for the real controlling actor instead of always blaming CO2 when CO2 appears to be a reluctant player in the temperature/concentration dance?
Jim
Some of you might find this of interest.
http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html
No. That is an assertion without any logic. Just as in the initial warming process, changes in temperature can occur first, with CO2 following. One could as easily posit that the long tail of cooling is exactly what is expected due to the long residence time of CO2. It takes longer for warming oceans to outgas CO2 than it does for geological absorption. One could posit that the long tail of cooling is a result of the long residence time of atmospheric CO2. Even now terrestrial sinks (incl oceans) only take up half the excess CO2 that is emitted into the atmosphere, and this has been the case for as long as there have been measurements of ocean CO2 uptake. Perhaps the bipolar process posited by Shakun occurs in reverse during glaciation – or some other process that brings down temperature leads CO2 absorption by terrestrial sinks.
But all this speculation is beside the point I’m making. Either one agrees CO2 is a greenhouse gas and will play a part (of whatever magnitude) in glacial transitions, or one distrots the scientific understanding by funneling a complex suite of processes into a binary either/or cause/effect argument.
Deglaciation takes 5k to 8k year. Even if CO2 accumulation lags temps for all places on Earth by 1000 years (ie, lags both Southern and Northern Hemisphere temp rise), the CO2 will contribute to warming (and cooling, possibly delaying it). You may argue about the magnitude of CO2 contribution, but trying to dismiss CO2 contribution outright by using the lag/lead argument is the same as denying CO2 is a greenhouse gas.
***
barry says:
July 25, 2012 at 6:33 pm
Accepting that CO2 has an effect (you can include Richard Lindzen, Roger Pielke Jr and Sr, Roy Spencer, John Christie, and any other actual climate scientist amongst those who have no doubt CO2 is a greenhouse gas that shoulod cause some warming if atmospheric content is increased) leads to the understanding that CO2 will amplify warming during the transition from glacial maximum top interglacial.
***
The paper (Roe) that Gail refers to shows a remarkable correlation between 65N summer insolation and ice-mass changes — something above 90%. If you assume ice-mass changes are a proxy for temperatures (dang good assumption), then that tight correlation means that little else (including CO2) is having an effect on temperatures. If CO2 had a significant effect, it would reduce that correlation, unless CO2 levels were exactly in step with the solar insolation changes. Obviously they don’t.
Roe’s paper IMO is strong evidence that CO2 changes & ice-mass changes (as a proxy for temps) have no significant correlation.
beng,
All I’m seeing is a litany of suggestions that rest on the idea that CO2 isn’t really a greenhouse gas. Your comment implies the same.
There are a slew of comments above that pit the issue as an either/or, lag/lead argument, as if chickens could not possibly lay eggs because they have been observed hatching from eggs. (“Eggs cause chickens, not the other way around!”) From my POV, no one is interested in correcting a very common meme that has been dropped all over this thread, ignoring what I’m saying in order to hop on to whatever pet paper/hypothesis/argument kills the CO2-contributes-to-glacial-shift notion. Care to join me in saying that the lag/lead argument suffers from the logical fallacy of assuming a single cause? At least I’d feel someone was actually dealing with what I’m saying here.
I doubt the Roe paper is going to change the picture very much, but please link to it if you think it’s really worth pursuing.
****
barry says:
July 26, 2012 at 8:06 am
beng,
All I’m seeing is a litany of suggestions that rest on the idea that CO2 isn’t really a greenhouse gas. Your comment implies the same.
***
How did you get that? I agree w/the basic, non-feedback CO2 pure radiation “theory”.
****
I doubt the Roe paper is going to change the picture very much, but please link to it if you think it’s really worth pursuing.
****
Look it up yourself if you have any basic curiosity. Takes a whole 10 seconds.
>>
Entropic man says:
July 26, 2012 at 1:11 am
Some of you might find this of interest.
<<
I remember the argument that other proxies (such as leaf stoma count) indicating higher levels of CO2 were in error, because ice cores showed a lower CO2 level. The argument then was that CO2 is a “well-mixed” gas and ice cores were as accurate as Mauna Loa readings (in fact, the Mauna Loa record was glued on to the ice core record).
Now that the ice core record is proving problematical in the area of CO2/temperature timing, the ice cores have to be discredited. I guess CO2 isn’t “well-mixed” after all.
Does this mean that the leaf stoma count proxy is now more accurate? You can’t have it both ways.
Jim
>>
barry says:
July 26, 2012 at 2:25 am
No. That is an assertion without any logic.
<<
It’s always interesting to see the individual with a complete disconnect from reality and logic accusing everyone else as being illogical.
>>
But all this speculation is beside the point I’m making. Either one agrees CO2 is a greenhouse gas and will play a part (of whatever magnitude) in glacial transitions, or one distrots the scientific understanding by funneling a complex suite of processes into a binary either/or cause/effect argument.
<<
The one who is “distrot-ing” scientific understanding is you. If a GHG works at level x, then it should also work at all levels greater than or equal to x. I’ll ask this again, if CO2 can lift the Earth out of the doldrums of an ice age, then why doesn’t it stop the temperature drop when its concentration is far higher?
>>
You may argue about the magnitude of CO2 contribution, but trying to dismiss CO2 contribution outright by using the lag/lead argument is the same as denying CO2 is a greenhouse gas.
<<
You’re setting up what is called a “straw man.” I don’t deny the GHE of CO2; it’s just a very weak GHG. I happen to be more realistic about it. Evidence shows it doesn’t play a major role in temperature control and probably doesn’t play a minor role. Even the IPCC tends to agree, because it gives CO2 the GWP of 1 (by definition). All other GHGs have a higher GWP. The IPCC even leaves out two major GHGs–water vapor and ozone. Try as you might, you won’t find a GWP value for either gas–the IPCC has conveniently excluded them in their definition of GWP.
Jim
Greenhouse is a THEORY. Only when a theory is replicated independently then it become LAW. Everyone will agree that water freezes at 32′ F/0’C. That is a law because it can be replicated with the same conclusion. The earth has heated and cooled for 7+ BILLION years. What was the cause in the past? I think Al Gore should be tried for fraud, misrepresentation and any other charges that can be brought against that yahoo.