Is the Current Global Warming a Natural Cycle?

Wow.

The obvious question is how to distinguish these events from red-noise. And if they are not just red noise, do they represent a local signal, or a regional signal. It would be a mistake to compare the expected regional trend with local variability, which is always expected to be greater. The simple check here is to demonstrate that the same events are found (at the same time) in the other Antarctic records. Are they?
Since you define HRWEs as being large than modern warming, it is inevitable that the modern warming will be the smallest of these.

Yes, it’s difficult to get accepted to the journals. For instance, Nature has an acceptance rate of about 1 in 15 papers submitted. You need not only a great story but also rock solid science.
Regarding the Mulvaney et al. study, you say, “The present global warming cycle lies within the range of these past natural warming cycles, suggesting that the present global warming cycle may be of natural origin and not caused by human activity–as climate skeptics have been arguing for some time.” This is a mischaracterization of their key finding. To quote the actual publication:
From the Figure 4 caption:
“Warming at JRI has been ongoing for several centuries, although the warming by 1.56 °C over the past 100 yr (red lines in a and b) is highly unusual in the context of natural variability. b, This is shown by a histogram analysis of temperature trends calculated in moving 100-yr windows of annual-resolution data from the JRI ice core starting at 2,000 yr BP.”
From the text:
“Over the past 100 yr, the JRI ice-core record shows that the mean temperature there has increased by 1.56 ± 0.42 °C (Fig. 4a). This ranks as one of the fastest (upper 0.3%) warming trends at JRI since 2,000 yr BP, according to the moving 100-yr analysis windows, demonstrating that rapid recent warming of the Antarctic Peninsula is highly unusual although not outside the bounds of natural variability in the pre-anthropogenic era (Fig. 4b). The JRI ice core shows that the recent phase of warming on the northern Antarctic Peninsula began in the mid 1920s and that over the past 50 yr the temperature has risen at a rate equivalent to 2.6 ± 1.2 °C per century. Repeating the temperature trend analysis using 50-yr windows confirms the finding that the rapidity of recent Antarctic Peninsula warming is unusual but not unprecedented.
The long-term climate history provided by the JRI ice core shows that natural millennial-scale climate variability has resulted in warming on the eastern Antarctic Peninsula that has been ongoing for a number of centuries and had left ice shelves in this area vulnerable to collapse during the recent phase of rapid warming. If warming continues in this region, as is suggested by its attribution in part to rising atmospheric greenhouse gas concentrations7, 23, then temperatures will soon exceed the stable conditions that persisted in the eastern Antarctic Peninsula for most of the Holocene. The association between atmospheric temperature and ice-shelf stability in the past demonstrates that as warming continues ice-shelf vulnerability is likely to progress farther southwards along the Antarctic Peninsula coast to affect ice shelves that have been stable throughout the Holocene, and may make them particularly susceptible to changes in oceanographic forcing24.”
Have a look at Figure 4b. If you don’t have access to the paper, you can see a thumbnail of the figure here: http://www.nature.com/nature/journal/v489/n7414/carousel/nature11391-f4.2.jpg . In the bottom panel the grey bars are a histogram of the number of times a given rate of warming is observed (degrees C per 100 years, X-axis). The peak of the histogram curve is at ~ 0. The red line is where we are at now.
Yes, the current warming “lies within the range of these past natural warming cycles”, but it is the is at the extreme limit, a fact which you neglect to mention. The authors’ conclusion is that we are getting close to exceeding the limits of stable conditions that have existed for >1500 years, and that the result may be an unprecedented collapse of ice sheets that have been stable over that period. And you think this is good news?

About what you would expect from an inherently chaotic system that is not near a bifurcation point.

“It appears to us that the current global warming signal lies well within natural limits. In this case, it seems to us difficult to argue that the current global warming signal is the result of human activity.”
It is wonderful to see this sort of thing in print. I have argued for some time that there is no CO2 signal in any temperature/time graph using data from the 20th and 21st centuries. Since there is no signal that is discernable above the noise of natural variations, it follows that the total climate sensitivity of the additional CO2 in the atmosphere is indistinguishable from zero. By “total climate sensitivity”, I mean the rise of global temperatures as a function of the change in concentration of CO2 in the atmosphere at current levels.

Profs. Davis and Taylor,
Your WUWT article is very good. I will be quickly reading the PDF that you link to.
This data is for the Antarctic (Vostok). Any thought on whether these are global events? Is there a way to tell from this data?
Events 37, 38, and 39 are of particular interest to me. I have found many papers using a variety of proxies that indicate the Arctic was warmer in that era (about 6000 years ago) than it is today.
You can see my list here…
http://climatesanity.wordpress.com/2008/10/15/dont-panic-the-arctic-has-survived-warmer-temperatures-in-the-past/
Tom Moriarty
ClimateSanity

Looks like the gatekeepers are still hard at it. Good thing this kind of censorship doesn’t extend to the blogosphere and these analyses are available for our consideration. Yet another strike against the peer review system that APOD commentators are so fond of.
It is frankly astonishing the ease with which the gate is slammed on submissions that don’t follow the alarmist agenda. What else are we missing out on?
It would probably be a popular thing to create a site that accepts science papers such as this. NotSeenAtNatureMag.com has a nice ring.

I have several problems with this paper. For example, dividing the data into “high” and “low” RWE’s on the basis of what is essentially an arbitrary number, and then applying mathematical analysis to the two data sets such as arithmetic means is pretty much meaningless. Change the arbitrary dividing line and the data sets change too. The same goes for the discussion regarding the events having common cause. The assumption seems to be a single common cause. Perhaps I’m reading this part of the explanation wrong, but it seems far more likely to me that 300+ events have more than one potential cause, and indeed, there are likely events that are “cooling causes” that could occur simultaneously with “warming causes” and cancel each other out, or produce a LRWE that otherwise would have been an HRWE and so on.
I think there’s a ton of good information in this paper that is important to understand and expand upon. There’s a lot of good info here, and a lot of potential for improving our understanding of climate. I just think there’s a lot of chaff mixed in with the wheat.

Of course the warming you noted was either spurious or noise!
They couldn’t replicate it with their models! /sarc (as if it’s needed.)
DaveE.

Poor peninsula, it is the only tiny piece of Antarctica which is warming /probably sea or air current changes/ so everyone is wanking on it, ignoring the cooling mainland of Antarctic.
Since CO2 is well mixed; the alleged increased downward IR should warm the surface uniformly and everywhere; it does not. Ice cores show the present is colder than thousands years of holocene, that recent warming was nothing different than previous events, that most of the recent warming started before CO2 has risen by few millionths. Never forget, that only the post-1975 warming is allegedly human-caused.

Doug H says:
September 5, 2012 at 11:31 am
My quote was from the published scientific article, not an analysis that was rejected by peer review and now is a blog post. Why was the data not published in a specialty journal, where virtually all papers are published?
================================
Because:
“The editor of Science Magazine replied that the results were not of sufficient general interest, suggested we submit the work to a specialty journal, and declined to proceed with external scientific review. Nature also rejected the paper without external scientific review, for reasons that we considered spurious.”
Thus a paper can be rejected by claiming “not sufficient general interest” if it in any way challenges the view that the 20th century rate of warming is extremely unusual. What they mean by “not sufficient general interest” is: “we don’t like what you found”. Or it can just be rejected offhand, or on the grounds that past warming events from the Vostok ice are “noise”, while current ones are pleasant music.
Since all contrary views are rejected one way or another, the peer review process in many sciences, but especially in cllimate science, functions effectively as a merry-go -ound of mutual flattery and validation, and also as collective gatekeeping of different views.
This makes the peer review process in climate science look particularly worthless, maybe even repulsive, and it makes those who invoke it as if it meant anything at all except cronism, look particularly silly.

Doug H says:
September 5, 2012 at 11:31 am
Tell us Doug H what you particularly disagree with about this article apart from the fact it’s been spuriously rejected by a journal having a reputation for readily accepting shoddy alarmist papers and rejecting papers that show opposing research?

Is the Current Global Warming a Natural Cycle? No.

WTF is an NWE

Is the Current Global Warming a Natural Cycle?
Ok, I’ll say it:
‘Well, duuuuh…”

[snip – I’m not interested in your denigrating opinions, especially when you haven’t the courage to put your name to them. Take a 48 hour time out. – Anthony]

What tjfolkerts said.
Seems like a lot of the warming events could be simply random variations in the measurement accuracy, given that the correlation of any individual measurement is not that close to temperature. But how does one find out?
This effect will diminish with a large quantity of data points, presumably; but the methodology in this paper does NOT demand large quantities of data points before declaring warming events.
So if there is indeed a significant +/- degrees-C error range for each measurement, requiring only 3 consecutive identical or increasing samples to declare a “warming event” would guarantee a lot of false positives over time, no? Think of flipping a coin hundreds of times, and counting every run of three or more heads as a significant event. Of course, in one’s own paper one can define as one pleases, but unless the temperature error range is lower than the temperature swings one is putatively measuring, especially with very short series (3 uncertainty-laden measurements, e.g.), it seems like there is a big risk of signal being swamped by noise.
Let me emphasize that I’m no expert on any of this, but I hope I’m a decently smart layman, and I’ve certainly no infatuation for CAGW theories and even less for the typical proposed “watermelon” solutions.

Considering the antarctic is cooling at the moment, I’m pretty sure the non existent warming would be within the bounds of previous warming events.
Of course the alarmist are quite happy to use the dubious uncalibrated ice core CO2 level proxy despite the data matching a decompression curve and having incorrect carbon dating while simultaneously disregarding other proxies and measurements that showed the CO2 level to be higher.

I imagine that you could even see this from the opposite side – instead of looking at the data to see if the current warming trend matches any prior HRWE’s, you could look at the DROPS in temperature. Kinda like a looking at low-rate cooling events (LRCEs; < -0.74C/century) and high rate cooling events (HRCEs; ≥ -0.74C/century).
Seeing how often they occurred in the history might help some people see just how damaging a rapid COOLING event might be (and compare them to events seen during the Maunder and Dalton Minimums).
Another thought – it's nice to see how long of a history we can get out of an Antarctic ice core (250,000 years). Pity that we can't get a comparable long-term ice core from the Arctic. That would sure clear up a lot about the history of GLOBAL sea ice.
Of course, lack of a long-term Arctic ice core could also mean that the ice hasn't been there very long.
Anybody know the OLDEST ice sample anyone has ever seen from the Arctic? I see stories about in the 50's, the age of the oldest circulating sea ice was upwards of about 10 years.

The only thing unprecedented about the current warming is that, for the first time, ecofanatics are claiming that the 47th similar period of warming in the last 235,000 years is ‘unprecedented’. Probably no such fanatics were around the other 46 times, or at least they werent taken so seriously. Perhaps we should all go back to our caves, if that is all we can achieve in 235,000 years.

Last night there was a very biased piece about the melting of the Arctic ices on BBC Newsnight, with a really balmy professor making out everything they predicted, but worse, was now happening. It was followed by a discussion between Peter Lilley MP and the new leader of the British Green Party who was quite potty, aggressive and incoherent (not an attractive advert for the ecowarriors)
Peter Lilley made a good fist of rubbishing the biased report, starting from the position of the underdog and with inadequate time to make his points. Like most public figures he had to concede global warming was happening, and accept IPCC science, in order to be allowed to be heard at all. I think this is tactical and he must be pretending on this score.
Being a “right wing” Conservative Peter Lilley will be dismissed without a hearing by the Guardian readers, but he is a good communicator with a good logical mind. We are missing having politicians from the left.
The new minister for the British minister of the Environment in the cabinet reshuffle is said to hate wind farms. Small indications that the playing field is less steep uphill struggle.

The paper’s Figure 4 shows the Roman Warm period (about 3.5C), the Medival Warm period (about 3.5C), and the Little Ice Age (about -1.8C) were truely global even reaching the Bellingshausen sea beside the Antarctic peninsula. That graph also shows that the warming near year 2000 (about 1.6C) has not shown the expected ‘bulk of the warming at the poles’ effect.
Interesting.
Link to the Nature paper:
http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html
John M Reynolds

Re: richardscourtney @ September 5, 2012 at 12:20 pm
Richard,
Unfortunately, I do not have the expertise to evaluate whether the results published in this blog mean anything or not. (Do you?) Thus, I am inclined, given the stated publication history, to agree with the experts who did review the work. I have chosen to not comment on an analysis that has in my opinion little weight because it has not only not been published, but has been rejected by referees as wrong. There is a huge amount of published data to get through…
And no, I do not have a crystal ball. Neither do you. But what I do know is that there is a ton of published evidence that suggests we may be at the beginning of a catastrophic change in climate that is at least being worsened by human activity. Even if this is more likely false than true, even if it has only a very small chance of being true, the potential harmful effects are massive. Therefore, it seems reasonable and humane to apply the precautionary principle. Sooner or later fossil fuels are going to run out, so why not just bite the bullet now, convert to other energy sources as fast as practical, and perhaps stop a catastrophe while we’re at it?
d

Re: Kasuha @ September 5, 2012 at 1:34 pm
I don’t know what you’re referring to about “sole proof”, but that’s not how science works. There is just evidence and the evaluation of evidence (so-called preponderance of evidence).

Re: D. J. Hawkins @ September 5, 2012 at 3:06 pm
Mulvaney et al. do not discuss high rate warming events (HRWEs). As I said, I’m no climate scientist, but I looked and can find no mention of HRWEs in searches of PubMed, Google Scholar, or even Google (other than this blog). I suspect that HRWEs are just an arbitrary analysis invented by Davis and Taylor, which they then applied to someone else’s data (“ice core data obtained from the Vostok site”). Based on their rejection by the referees, HRWEs may not be a particularly powerful analytical tool. (But again, they have not provided enough detail to determine if this is the case.)
It’s a real shame that you can’t access the Nature article. All scientific publications should be open access. Well, at least we are slowly moving in that direction. Maybe you can access it via your local community or university library?
In lieu, here’s a summary. (NB. You can see thumbnails of the figures at http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html .)
Mulvaney et al. drilled their own ice core in an region of particular interest because it is warming exceptionally quickly and because of recent ice sheet collapses (James Ross Island). The 363.9-m-long core “extends into the last glacial interval (Fig. 2, Methods Summary and Supplementary Fig. 1). Evidence of the glacial age ice is found in the final 5 m of the JRI ice core; initial estimates suggest the record may extend to ~50,000 yr BP (by convention, 0 yr BP means AD 1950).”
They did a temperature reconstruction to >14,000 yr BP. They found:
“The Holocene temperature history from the JRI ice core is characterized by an early-Holocene climatic optimum that was 1.3 ± 0.3 °C warmer than present (Fig. 3).”
(“Early-Holocene” appears to mean ~12,000 – 10,000 yr BP, based on Fig. 3.)
“Following this widespread early-Holocene climate optimum, temperature on the Antarctic Peninsula decreased and the JRI ice core documents a long interval of stable climate that persisted from ~9,200 to 2,500 yr BP (Fig. 3). During this interval, the mean temperature anomaly, of 0.2 ± 0.2 °C, indicates that conditions at JRI were comparable to the warm conditions observed at this site over recent decades. ”
“The late-Holocene development of ice shelves fed from the northeastern Antarctic Peninsula seems to be related to millennial-scale climate variability in the region (Figs 3 and 4a). After 2,500 yr BP, the JRI isotope record documents pronounced cooling to temperatures that were on average 0.7 ± 0.3 °C cooler than present between 800 and 400 yr BP (AD 1150–1550), and on a decadal timescale temperatures may have at times been more than 1.8 ± 0.3 °C cooler than present. ”
“Sustained warming at JRI began ~600 yr ago (Fig. 4a). Lake sediments from Beak Island in Prince Gustav Channel also indicate warming beginning at ~AD 141018, and together these records demonstrate the absence of a widespread Little Ice Age signal on the Antarctic Peninsula that was comparable to Northern Hemisphere climate22 (Fig. 4a). The overall rate of pre-anthropogenic temperature increase at JRI from AD 1400 to AD 1850 equates to 0.22 ± 0.06 °C per century. However, there are times in this interval when warming occurred much faster. Using annual-resolution data, trends were calculated for the JRI temperature record since 2,000 yr BP over moving 100-yr intervals stepped in 1-year increments (yielding 1,958 100-year analysis windows) (Fig. 4b). This analysis indicates that rapid warming trends exceeding 1.5 °C per century occurred at JRI during the intervals spanning AD 1518–1621 and AD 1671–1777, and that trends exceeding 1.25 °C per century occurred during the interval AD 296–415.
Over the past 100 yr, the JRI ice-core record shows that the mean temperature there has increased by 1.56 ± 0.42 °C (Fig. 4a). This ranks as one of the fastest (upper 0.3%) warming trends at JRI since 2,000 yr BP, according to the moving 100-yr analysis windows, demonstrating that rapid recent warming of the Antarctic Peninsula is highly unusual although not outside the bounds of natural variability in the pre-anthropogenic era (Fig. 4b). The JRI ice core shows that the recent phase of warming on the northern Antarctic Peninsula began in the mid 1920s and that over the past 50 yr the temperature has risen at a rate equivalent to 2.6 ± 1.2 °C per century. Repeating the temperature trend analysis using 50-yr windows confirms the finding that the rapidity of recent Antarctic Peninsula warming is unusual but not unprecedented.
The long-term climate history provided by the JRI ice core shows that natural millennial-scale climate variability has resulted in warming on the eastern Antarctic Peninsula that has been ongoing for a number of centuries and had left ice shelves in this area vulnerable to collapse during the recent phase of rapid warming. If warming continues in this region, as is suggested by its attribution in part to rising atmospheric greenhouse gas concentrations7, 23, then temperatures will soon exceed the stable conditions that persisted in the eastern Antarctic Peninsula for most of the Holocene. The association between atmospheric temperature and ice-shelf stability in the past demonstrates that as warming continues ice-shelf vulnerability is likely to progress farther southwards along the Antarctic Peninsula coast to affect ice shelves that have been stable throughout the Holocene, and may make them particularly susceptible to changes in oceanographic forcing24.”
Over and out, got work that needs doing. Best of luck,
d

Richard,
I did read the blog article. You missed my point entirely. If you had read the post I was replying to, maybe it would make more sense to you. (Also, if you had read my comments that Davis and Taylor don’t provide enough details to evaluate their work, you should have concluded that I read their blog article.)
I was responding to a question from D. J. Hawkins about whether Mulvaney et al. found similar HRWEs to Davis and Taylor. My answer was no, because they did not do the same type of analysis, which does not appear to be standard, does not appear to be used by anyone else, and which appears to have led the referees to reject the paper because due to statistical insufficiencies. That is why I chose not comment directly on their results but instead to point out that they may be meaningless and we have no way of judging whether or not they are based on what they have “published” here.
D. J. Hawkins’s confusion is quite understandable, because in the blog article, Davis and Taylor describe their analysis as “similar but more extensive” to Mulvaney et al, which is a bit of a stretch. But D. J. Hawkins and possibly others do not have access to the article, so cannot judge the differences between the two reports. To help, I went on to described the analysis of Mulvaney et al., including excerpts of a large portion of the report. (I wish I could post the whole thing.)
That was the point of my post. I’m terribly sorry if my arguments aren’t of help to you personally, or if you don’t like them. But perhaps other people in the thread will find them useful or interesting? Who do you think you are, to dictate who speaks and who does not?
In any case, you will have your wish because, as I said, I don’t have time to continue with this fruitless discussion. I hope that my previous posts may be of use to someone because this is an extremely serious issue that should understood based on the best available evidence.
Good luck and goodbye,
d

Is this a new AGW argument – that the Vostok – and other – ice core records, that have been the subject of substantial research into past climate variation, are now considered to show nothing more than “red noise”?
Are ice ages “red noise”? One can sense how, once the AGW team get to a suitable high of confidence, that ice ages will be their next target – some are already no doubt preparing narratives which question whether past ice ages were a measurement artefact.
The end goal is of course an inquisitorial imposition of belief in a totally uniform climate for all of earth’s history until the late 20th century.

richardscourtney says:
September 6, 2012 at 10:24 am

I really like your correct restatement of the precautionary principle, and would like to quote it to others (including the Republican primary winner from our town who will go up against the rabid warmist Rep. Ed Ma[la]rkey in November). However, I’m not sure what you intended by the “end of a wire” phrase in this sentence:

. . . the ONLY sources of the needed energy are fossil fuels and nuclear power. The major increase has to be in fossil fuel use because not everything can be powered from the end of a wire.

Do you mean that fossil fuel plants can be situated more locally than nuclear ones? Or am I missing something?
/Mr Lynn

No. our mistakes – concrete jungles, deforestation, and deserts formation have disturbed cooling system causing global warming.