WUWT readers, Figure 4 is noteworthy, because it points out the trend of 20th century warming in context with other periods of warming derived from the ice core record. I suggest you bookmark this post and that graph, as it tells a simple but indisputable story. – Anthony
Guest post by Frank Lansner
In a recent article:
http://wattsupwiththat.com/2010/09/08/working-925-what-a-way-to-make-a-livin-at-agw/
I estimated the total raw CO2 warming to be around 9,25 times the warming effect of one CO2-doubling:
Fig 1
Heat from one CO2-doubling (the “CO2-sensitivity”) has been estimated by IPCC and J. Hansen to be 3K or even 6K, including feedbacks. The 9,25 CO2 “doublings” cannot all have such a huge effect including feedbacks, so present day conditions on Earth must be extraordinarily heat sensitive (at least according to the IPCC).
Claim: Just a tiny temperature increase under present day conditions (like raw effect of one single CO2 doubling) should result in temperature jumps of up to 3 – 6 K.
Is this claim supported by evidence?
Fig 2
I have examined high quality Vostok temperature ice core data from the interglacial periods of the last half million years. These warm periods are the best evidence we have from Earth to examine the dynamics of present day climate on Earth.
We are looking for other huge temperature rises of 3K – 6 K that should result from just minor temperature rises.
Below I have identified all temperature rises of the Vostok data fulfilling the following criterion: “Temperature at the beginning of temperature rise must be at most 1 K below today’s temperatures indicated by -1K anomaly in the Vostok data. Next, the examined periods must be at most 300 years in length (we want to focus on the warming effect of one century time intervals) and finally, the initial temperature increase from glacial to interglacial is not included”:
Fig 3
96% of all temperature increases are between approx 0 and 1,4 K, only in one situation (approx 1 %) we find an interglacial temperature increase of almost 3 K.
That is: Under present day like conditions, temperature rises of 3K are very rare indeed, while smaller temperature rises of around 1 K are abundant and normal.
The interglacial periods shows no temperature peaks of the size interval larger than 3K. If in theory a minor warming of 0,5 – 1 K should lead to a 4-5-6 K warming including feedbacks, why are there no such peaks in the previous interglacial periods? There are plenty of 1K warming peaks (resulting of from all kinds of natural mechanisms) to induce the massive positive feedbacks that IPCC and Hansen expects.
Fig 4
The average interglacial temperature rise (from these data criteria) shows a warming of 0,65 K and lasts 113 years. In average they begin at –0,17K and end at +0,48K. (These averages are only to some degree dependent of my definition of interglacial periods – unless my definition of interglacial periods are totally wrong.)
The average temperature increase for these data of 0,65 K over 113 years – does not exactly make the modern temperature increase 1900 – 2010 of around 0,6-0,7K appear that special, does it?
Fig 5
The data tell us more: When the time intervals exceed around 100 years, the average magnitude of the recorded temperature increase does not increase. This is interesting and surprising because a longer interval should give time for a larger temperature increase. But on average the time intervals in data longer than around 100 years shows smaller net temperature rises indicating – unless this is a coincidence – that temperature peaks of the interglacial periods in average lasts around roughly 100 years.
Via Joanne Nova, I got a feedback to this result from George White:
“The analysis is consistent with long term averages changing more slowly than short term averages. The correlation drop at 100 years is because of a periodic effect of about 180 years. After 90-100 years, the direction of the temperature change reverses and the deltaT drops. If the analysis is continued, a second peak should appear between 250 and 300 years as a result of the second cycle of this period showing up with a minimum centered between the peaks. ”
Interesting, and thanks to George White.
When nature has warmed the planet over 100 years, this warming seems to END rather systematically. If positive feedbacks were strong why do temperature rises end so systematically? At least this warming-turn-off suggest that:
Natural forces or perhaps negative feedbacks are stronger than positive feedbacks after just a limited warming over 100 years
In addition, we see very few small temperature increases (of the order of 0 – 0,15K) for time intervals less than 150 years. On the other hand, the longer time intervals shows several of these tiny temperature increases. This indicates – unless it’s a coincidence – that if at first, temperature is on the rise, it often continues to rise until a significant temperature rise is reached. In other words: Temperature variability is the norm and constant temperature seems unusual.
Conclusion
Nature has provided us with data telling a simple story: For periods on earth comparable with today, we see many examples of temperature increases in the magnitude of 1 K for all kinds of natural reasons. Very rarely does any temperature rise (via supposed positive feedbacks) reach 3 K within 100 years.
It is thus surprising that IPCC and others with big confidence can claim large temperature rises of up to 3 – 6 K as most likely result from just a minor temperature increase, for example induced by CO2 warming.
More, it appears (fig 4.) that the temperature rise of 0,7K from 1900 to 2010 is as normal as can be when comparing with other temperature rises during other warm periods.
***
Comments
1) I have defined “interglacial temperature rises beginning at -1K compared to modern temperatures, no lower. On this definition I found that the temperature increase 1900-2010 was normal. If I had defined interglacial periods as starting at -2K, then there would have been a few more temperature increases in the area 1-2K which would make the present temperature rise appear smaller in comparison. However, the limit -1K for interglacial periods mostly is in compliance with the nature of the interglacial periods. When first we have interglacial period its not often we find temperature in the area under – 1K. Therefore I found -1K to be the best choice to limit interglacial tendencies. Also, temperatures should resemble today’s temperature range as close as possible.
2) I have used 0,7K for the temperature increase 1900-2010. This is obviously highly questionable due to significant UHI measuring problems and adjustment issue that is likely to have exaggerated the temperature increase 1900-2010. On the other hand, temperature variations at Vostok are likely to be larger than global temperature changes, so perhaps a qualitative compare is somewhat fair after all. At least, if you claim that the present temperature increase is extraordinarily large, I think one should show data that supports it. And, as I showed, Vostok data does not really support the claim.
3) By Joanne Nova: “In the past natural temperature rises we should also see the positive feedbacks at work. But it is very difficult to isolate the exact amount of warming due to the natural forces vs that due to the natural feedbacks. Where does one stop and the other start? In any 3 degree rise, how much was due to the forcing, and how much to the feedback? If positive feedback was strong we would expect to see examples of it occurring in the past ice cores.”
Frank: This is very true and makes this topic a little fluffy to deal with. However, the absence of 3K – 6K temperature rises in the interglacial periods means that there should not have been any natural warming excl feedbacks of just 0,5 K or so (matching the raw CO2-sensitivity warming). And we still can see that the temperature rise 1900 – 2010 is just a normal interglacial variation.
4) Hereafter it could be interesting to do analysis using Dome C core temperature data that has twice a many data points for temperatures which may refine the results to some degree.
Source used for Vostok data:
http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_data.html
See also:
http://joannenova.com.au/2010/08/ice-core-evidence-no-endorsement-of-carbons-major-effect/
http://hidethedecline.eu/pages/posts/925—a-factor-that-could-close-the-global-warming-debate-193.php
http://wattsupwiththat.com/2009/01/30/co2-temperatures-and-ice-ages/
mrpkw says:
December 9, 2010 at 4:17 am
Actually, we should all be cognizant of typos and willing to point them out and have them corrected. Wasn’t it supposedly a “typo” that was used as an excuse by some regarding glaciers that were to disappear in the Alps prematurely? Don’t let critics jump on any of these fine articles and distort the content because of typos.
Stand by for the predictable argument from the advocates of Catastrophic Anthropogenic Global Warming. It will come in the form along these lines:
“But by analysis the Earth should be in a cooling phase of 1° per century and we have unprecedented warming of over 1° per century yielding a true rise of over 2°.” Blaw, blaw, blaw … and it is all caused by human activity and carbon pollution from burning dangerous fossil fuels.
So essentially the accused of being oil sponsored by coal inflated conniving heinous evilly grand manipulator of cheating skeptics are essentially right, and the Great Poobah believers are, as always has been, wrong.
Bloody hell that’s what I’ve been writing when I wrote what I had writ.
The fact that some 4.5 billion years after the creation of the Earth, we are here able to debate this issue in itself establishes that the Earth’s climate is self regulating and that if there are any tipping points, they are almost impossible to achieve. If all the violent forces of nature have not led to a tipping point, there is nothing that man can realisticic do to create one. Just think of the past climatic and geological history of the Earth and what she has been through to realise that the present scaremongering is simply ridiculous.
@Lanser
“We are looking for other huge temperature rises of 3K – 6 K that should result from just minor temperature rises.”
While you’re doing that please also look for huge snowfalls that result from just minor snowfalls and huge floods that result from just minor floods.
Like duh.
Now publish it in a scientific journal … let is stand the critique of people more experienced than us. Of course some would claim the peer review process is corrupted (I strongly disagree), but if that were the case, on what grounds do non-scientists know which plausible person to take seriously.
RockyRoad says:
December 9, 2010 at 6:04 am
mrpkw says:
December 9, 2010 at 4:17 am
I know you don’t like nit pickers pointing out typos, but should it be “19th” not “29th” century?
Actually, we should all be cognizant of typos and willing to point them out and have them corrected. Wasn’t it supposedly a “typo” that was used as an excuse by some regarding glaciers that were to disappear in the Alps prematurely? Don’t let critics jump on any of these fine articles and distort the content because of typos.
========================================================
I kind of agree, but Anthony made the (good) point sometime back that he does an incredible amount of work running this blog and it is tiresome to see a lot of nit picking
Keep up the great work Anthony !!!.
Excellent analysis …
I think about the only sure thing anyone can say about climate, is ever since plate tectonics closed the Isthmus of Panama, some 3 million years ago, the next glaciation epoc is right around the corner. And nothing we can do about that. If we were smart, we would prepare for that inevitable eventuality.
BUT — The fact that we try and measure things with the instrument precision we have today, with instrument precision of yesterday, means we have at best a guesstimate. And therefore, most of the deviation what we see would fall within the measurement errors of yesterday’s precision. It’s the dreaded consequence of advancing technology.
Look at it this way, not too long ago, people thought the Earth was the center of the universe — Just a minor error. BTW, nothing I say here faults the analysis, only adds caution and context.
Very well done article, it will take some time to digest and research….. but none the less very well done
The standard response to this very cogent post is that CO2 heating is hiding in natural variation just waiting to bite us in the ars when we least expect it. What was that seriously funny statement? Climate change has (or will) worked its way into weather and once there you can’t get rid of it? Or something like that. These pro-AGW pseudo-sciency arguments are beginning to compete with that very funny scene in Monty Python’s “The Life of Brian” in the courtyard filled with “The end times are coming” preachers.
The effect of Co2 is COMPLETELY drowned out by other natural processes (i.e. water vapor to name just one of many). I cannot see how anyone can make an issue of Co2.
Anyone trying to claim long droughts, harsh 5 month winters, fierce tempests, devastating floods, or whatever else weather phenomena are “unprecedented” or “extraordinary” they need to read this.
“Weather has been documented by early meteorologist and historians for many centuries. A Chronological Listing of Early Weather Events provides a weather resource for years 0 A.D. to 1900 A.D. ” by James A. Marusek.
http://www.breadandbutterscience.com/Weather.pdf
Fascinating and revealing.
kzb says: The criticism of this will be that we are now in special times, that is, there is an anthropogenic input of CO2. Therefore there is no reason to expect this warming trend to behave like past warming trends.
The article is saying that all past warming trends have been self-limiting. The warmists will say (with justification) “but it’s different this time !”.
These are probably the most-feared words on Wall Street: TTID. This Time It’s Different. So many big, bad mistakes there start with thinking that this time is special, and we can blithely ignore all the history. And of course you, the awe-struck customer, can only get that vital insight from little old me, the salesman with the bright idea.
This approach should always set off loud alarm bells. Always.
First, let me say that I’m firmly in the “skeptical” camp, but one thing concerns me here:
you’ve looked at the past when natural occurrences, whatever they may be, caused the ebbs and flows of the temperatures.
The addition of CO2 into the atmosphere by humanity is, arguably, not a natural occurrence, is it not? Does this unnatural act then operate outside of anything we’ve seen in the past?
According to the first graph, I suspect that if antropogenic contributions were adding to an atmospheric CO2 level of say, 40 ppm, the argument could be made that the additional CO2 might make a noticeable difference, but at the 300 + ppm level the contribution doesn’t seem to be significant.
Perhaps I’ve answered my own question?
Thanks, Frank. I’ve always wanted to plot the rises in temperature during those earlier warming periods.
Using the exact same data that is used to prove global warming,
a person could make a more solid argument that CO2 drives cooling.
And the CO2/temp data would support it…………
NASA/NOAA Climate Sensitivity is below 1.65 degree Celsius.
http://motls.blogspot.com/2010/12/nasa-noaa-climate-sensitivity-is-below.html#more
“unless my definition of interglacial periods is totally wrong.”
more grammar police..sorry.
Very nice analysis. Yet again it’s up to the CAGW crowd to prove the current warming is unusual, and that their models are realistic.
An excellent and interesting article technically. I was bothered, though, by a number of subjects and verbs disagreeing in number (plural verb with singular subject or vice versa). I would guess that English is not the first language of the author, and I would count myself lucky if I could write even a fraction as well in his language, but having a competent English editor would have helped with the article.
IanM
Another blow to the modern Puritanical (AGW) belief system….
Time for another “Sinners in the hands of an angry Gaea ”
speech by Algore-in the middle of a blizzard.
Thank you, Frank.
As I understand the graph depicted in your Figure 2 (Petit et al) was produced by applying a 70-year smoothing to the original data. Did you use the raw data before smoothing for your analysis? The one thing the atmospheric CO2 measures from stomata and the 19th century instrumental readings analyzed by Georg Ernst Beck show is higher average levels and considerable variation from year to year.
Antarctic air temperature derived from ice core temperature can’t be used as a proxy for global average temperature with fine granularity. Supposedly these past two decades are the warmest in at least 1000 years but Vostok actually got a little colder. The oxygen balance in snowfall (one method of determining air temperature in the past) at Vostok, which gets about a 2 millimeters snowfall per year, is going to be the average of many years. It takes 500 years to accumulate a meter of snow while fierce winds have been pushing it around relentlessly drifting back and forth keeping it well mixed. The same mixing will also keep absolute ice temperature at best an average over a similar amount of time. So all you can really say from Vostok core data is that there weren’t any lengths of time where average temperature over a period of centuries didn’t exceed this or that and only really at the south pole which may or may not have tracked the northern hemisphere or even much of the southern hemisphere.
I think the main point is that CO2 is higher now than can be seen in the core data for past periods and while that is also subject to averaging over decades it at least appears to track global CO2 partial pressure (well mixed atmosphere). So assuming the CO2 spike from 280 to 390ppm (and growing) is something novel, which it appears to be at least as far back as ice cores go, then we are in unexplored interglacial territory.
Personally I hope this unexplored territory is an indefinite and perhaps very long lived end to the ice age of the past few million years but I tend to doubt anthropogenic greenhouse contribution is enough to prevent the return of the glaciers more or less right on schedule.
The false claim about 10th century warming is based SOLELY on Mann’s hockey stick. Neither CET, nor Greenland/Antarctic ice cores suggest anything extraordinary has been happening. Btw, the “anthropogenic” warming is only the post-1975 one according to the IPCC, do not forget.
Humbug, Baa : Yes! Scrutiny is what it takes to take this futher 🙂
Thanks.
posted by JohnWho
>> The addition of CO2 into the atmosphere by humanity is, arguably, not a natural occurrence, is it not? Does this unnatural act then operate outside of anything we’ve seen in the past? <<
My response to your question is that CO2 levels have been much higher in the past than they are now and yet temperatures obviously didn't go off the charts. In fact, from what I have read, there appears to be very little correlation between historic CO2 levels and temperature. Since the natural CO2 molecule is the same as the anthropogenic CO2 molecule (in fact they are all natural) I see no reason why current (and historically low) levels of CO2 should be any concern at all. I believe most AGW modellers tacitly admit this when they introduce mythical "forcings" into their models to achieve the desired temperature increases.