Normally, I don’t bother to discuss paleoclimatological reconstructions. The reason: most try, some through questionable methods, to illustrate that the recent warming is unusual and could only be explained by the increased emissions of manmade greenhouse gases. And that’s the same claim being made for the instrument temperature record by proponents of the hypothesis of human-induced global warming. But as I’ve been illustrating and discussing for 4 years, ocean heat content data and satellite-era sea surface temperature indicate Mother Nature is responsible for the warming of the global oceans, see here [42MB], so I don’t find claims of unprecedented, human-induced global warming to be realistic. However, I noticed something that’s very obvious in an illustration from a recent paper that’s getting some press, and I wanted to make it easier to see, for those who’ve overlooked it.
There have been numerous discussions about the Kaufman et al (2013) paper “Continental-scale temperature variability during the past two millennia”, also known as the PAGES (PAst Global changES) reconstruction. ClimateAudit has been reporting on it for a number of days. See Steve McIntyre’s posts here, here and especially here. WattsUpWithThat has discussed the paper here and here. SkepticalScience responded to the paper as could be expected here. RealClimate’s post includes an interesting illustration, which drew my attention to the paper. It’s a modified version of Figure 2 from Kaufman et al (2013). I’ve included the original version from the paper as my Figure 1. The source of the illustration is here.
Figure 1
The illustration presents their color-coded temperature anomaly reconstruction as 30-year mean temperature anomalies for the individual regions, which are further identified in the map (Figure 1) from the Kaufman et al (2013). Clearly, there has been, as the title of the paper states, “Continental-scale temperature variability during the past two millenia”. In some of the regions, recent temperatures are warmer than they have been in the past, but in others, the recent temperatures have been exceeded in the past or are comparable. Here, let me make it easier to see.
I’ve modified Figure 2 from Kaufman et al (2013) to show only the regions where recent temperatures are warmest in my Figure 2. Those 3 regions include only the Arctic, Asia and Australasia. In my Figure 3, I’ve modified their illustration to show the regions where recent temperatures are cooler than or comparable to past temperatures. Those 4 regions are Europe, North America, South America and Antarctica.
Figure 2
####
Figure 3
Something else also stands out in the 3 regions where current temperatures are warmest, my Figure 2. Only one of the reconstructions extends back the full 2000 years. Would Asia and Australasia have warmer temperatures than those we’ve experienced recently if their reconstructions could be extended farther back in time? Dunno.
CLOSING
Clearly, the claims of unprecedented recent temperatures are not supported by the regional reconstructions. Four of the seven regions presented by Kaufman et al (2013) clearly show that recent temperatures are comparable to past temperatures or they have been exceeded in the past. This can also be seen in the individual graphs presented in Steve McIntyre’s post here. Now, hasn’t this been one of the arguments by climate skeptics since the hockey stick was introduced—that the hockey-stick appearance is a regional phenomenon? That regional reconstructions show current temperatures have been exceeded in the past in many parts of the globe?
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Thanks Bob. It is hard to believe unprecidented claims that do not even look at areas, eg. Asia and Australia, and where are Africa and S. America? Looks like they only looked where they wanted, and ignored most of the landmass.
We had a bunch of volcanoes going off between 1200 and 1850 and none between 0 AD and 1000 AD? Interesting (yet unbelievable).
Which is more frightening, North Korea with nukes, or that a branch of influential scientists continue to mercilessly torture data into confessing a climate change disaster that is clearly not happening?
@DirkH – Pompeii and Herculaneum never happened?
Shame on those Romans for exaggerating!
”hasn’t this been one of the arguments by climate skeptics”
I suspect we’ll be seeing more and more “skeptic arguments” being slipped into the peer-reviewed literature, rebranded of course without any acknowledgement that there was ever anything going on here but the normal progress of science. It’s becoming more and more obvious to more and more people that not only did “climastrologists” jump to the CAGW conclusion before sufficient evidence accumulated but that the conclusion has little hope of being proven right at this point. It now appears to all but the true believers that natural climate “forcings” overwhelm any tiny influence of burning fossil fuels, but climate science has to climb down a pretty tall ladder they’ve ascended and start building a new ladder that doesn’t exclude evidence that doesn’t fit the CAGW narrative. This could take decades, perhaps generations, but in the age of the internet who knows perhaps the rate of descent will be unprecedented.
John West, you write “This could take decades, perhaps generations, but in the age of the internet who knows perhaps the rate of descent will be unprecedented.”
As I have noted many times, future empirical data on such things as global temperatures and Arctic sea ice extent, hang over CAGW like a Sword of Damocles. The warmists have no influence over future empirical data. What this data will be, we do not know. But it is not difficult to think up scenarios where this data could cast so much doubt on the validity of CAGW in the very near future, this year for example with Arctic sea ice, that the whole house of cards that is CAGW could come crashing down.
Good points Bob, and yes, it’s a pity about lack of the full time range in most of the data sets.
The pattern that my eyes fancied they saw in the original figure was that those data sets that showed higher temperatures in the past had lower ones in the present, and vice versa, which looked to me as though there was a similar sort of periodicity in each data set, but the timing of this was staggered betweeen different regions.
I therefore expected your post to point this out as well, and to conclude that this was a demonstration of the differential influence of oceanic circulation between the various regions.
Damned neural pattern-recognition software!
@ur momisugly tisdale
3 out of 4 not warmer than past are on the SH, there is a lot of sea and ocean there, warming goes slower;
I must sound a bit like a broken record, but every time I see a reconstruction which states it is warmer now, in the Arctic, than it was a thousand years ago, I point out the Vikings of Greenland could not have lived as they did, at current temperatures. (They are trying to raise livestock in Greenland once again, but it require some imports (which Vikings didn’t have,) and at nowhere near the levels Vikings achieved.)
The following paper is great reading, about Vikings in Greenland in general, and the excavation of the “Garden Under Sand” settlement in particular:
http://www.collectionscanada.gc.ca/obj/s4/f2/dsk2/ftp04/mq22551.pdf
The following quote from that paper ought send farmers hustling up to Greenland, if it is truly warmer now.
“For the Vatnaverfi district of the Eastern Settlement it is estimated that 100.000 sheep and goats may have been pastured at the height of the Norse period (Jacobsen 1987). The resources these animals required included about 700.000.000 kg of hay and between 36.500.000 to 73.000.000 litres of water annualy or 1.917.808 kg of fodder and 100.000 to 200.000 litres of water daily.”
(And that quote doesn’t even mention the 2000 cows, which are not as tough as sheep from Iceland.)
Jim Cripwell says:
April 23, 2013 at 6:08 am
But of course they do. The warmists are in control of all the data-collection systems. They can report any numbers they like. There can be icicles hanging from your ceiling and they’ll report the warmest season on record. Even Anthony’s nemesis, BEST, which is an honest attempt to grade weather stations for quality, is using someone else’s numbers.
Pardon me for being a cynic but if I were one of the bad guys, that’s exactly how I would “hide the decline.”
What really will be irksome is that, when the scientists finally admit that there has been no anthropogenic warming, they will do so in a way that gives them all the credit for “discovering” that and none to the people who’ve fought to expose the lie for decades. It’s like the explanation that Soviet Communism fell because Gorbachev, you know, was a nice guy and wanted to disassemble it and give his people more freedom, and not because the US was so successful that the Soviet Union went broke trying to keep up. Nope, no Ronnie Reagan, no “Star Wars,” just that it was time for that nice Mr. Marx and Mr. Lenin to step off the world stage after 75 years of murderous dictatorship. Thus it will be with the warmists.
maarten says: “3 out of 4 not warmer than past are on the SH, there is a lot of sea and ocean there, warming goes slower…”
But that does not explain the very obvious cooling in Antarctica, which should reflect sea surface temperatures of the Southern Ocean.
oldfossil writes “But of course they do.”
Sorry, I completely disagree. BEST is not original data. Thermometers in Stevenson screens, or remote sensing satellites meausure temperature. Satellite cameras measure sea ice extent. The warmists have no control of the raw data that is actually measured.
from a recent study…
“The summer ice melt in parts of Antarctica is at its highest level in 1,000 years, Australian and British researchers reported on Monday, adding new evidence of the impact of global warming on sensitive Antarctic glaciers and ice shelves.”
Seems that the regional temps above would not support such a claim, and may explain why they only went back 1000 years. Of course they cherry picked a location.
Bob Tisdale:
“Normally, I don’t bother to discuss paleoclimatological reconstructions. The reason: most try, some through questionable methods, to illustrate that the recent warming is unusual and could only be explained by the increased emissions of manmade greenhouse gases.”
One test of intellectual honesty is this: “Can you present your opponents argument fairly, or do you rely on distortion?”
Lets see what the author of this study said.
Kaufman:
“The pre-industrial trend was likely caused by natural factors that continued to operate through the 20th century, making 20th century warming more difficult to explain if not for the likely impact of increased greenhouse gasses,” Kaufman said.
According to Bob his opponents argument is this : recent warming could ONLY be explained by GHGs.
According to the author his argument is: 20th century warming is MORE DIFFICULT to explain if not for GHGs.
You see how easy it is to defeat what Kaufman never argued?
A minor point, but I find it interesting that the North American pollen data doesn’t entirely agree with the tree rings. The most recent data seems to show tree rings see it is warmer than normal, while pollen says, “Ho hum. Normal.”
“Those dirty rings! You try soaking them out. You try scrubbing them out. But still you have…”
(From an incredibly annoying old TV commercial in the United States.)
“Would Asia and Australasia have warmer temperatures than those we’ve experienced recently if their reconstructions could be extended farther back in time? Dunno.”
Recently, some scientists published a study showing that there was a medieval warm period on the “great Chinese plateau,” also known as the “top of the world.” I think that article was discussed in a post on WUWT.
Mosher,
“MORE DIFFICULT” Does that mean 95% certainty, robust, or what? These studies always have these types of weasel words (could, should, might, and now more difficult). Of course they are not claiming 100% certainty. Nor do we think those debunking these AGW studies claim 100% certainty.
Maybe you can show where the study ‘presents your opponents argument fairly’.
“Now, hasn’t this been one of the arguments by climate skeptics since the hockey stick was introduced—that the hockey-stick appearance is a regional phenomenon?”
I missed that one. Mann and other Alarmists have argued that the Medieval Warm Period is a regional phenomenon. They have done so in the face of powerful evidence to the contrary. The article under discussion here provides more evidence that the Medieval Warm Period is not a regional phenomenon.
What’s happening to Climate Audit format? is it me or something’s being worked on?
Steven Mosher says: “You see how easy it is to defeat what Kaufman never argued?”
Did I mention Kaufman in the sentence you quoted? Nope. I wrote and you quoted: “Normally, I don’t bother to discuss paleoclimatological reconstructions. The reason: most try, some through questionable methods, to illustrate that the recent warming is unusual and could only be explained by the increased emissions of manmade greenhouse gases.”
I made a general statement and you, Steven, applied it to Kaufman et al.
Regards
Bob,
Touché!
One recent study showing a Chinese medieval warm period is:
http://notrickszone.com/2013/04/15/back-to-the-penalty-box-chinese-paleo-climatolgists-slap-down-high-sticking-michael-mann/
A survey article on studies showing the MWP in China is:
http://www.co2science.org/subject/m/summaries/mwpchina.php
RE: Theo Goodwin
Thanks for those links.
The first link makes me wonder what sort of data Mann used, to create his map that shows Tibet as abnormally cold during the MWP, when it was in fact warmer than today.
The second link makes me wonder more, for those studies date from before Mann came up with his map, and they also suggest it was above normal where Mann states it was below normal.
Has Climate Audit gone over the data for Mann’s map?