From The Earth Institute at Columbia University comes another tree ring hockey stick. I have to laugh though at the choice of graphic for the press release, which shows a weather event (Euro heat wave) in 2003, rather than showing us the science, like maybe a reconstruction. I wonder what absurd assumptions or tricks (like Zombie proxies) Mr. McIntyre will find in this one that he hasn’t already – Anthony
Earth’s current warmth not seen in the last 1,400 years or more, says study
Fueled by industrial greenhouse gas emissions, Earth’s climate warmed more between 1971 and 2000 than during any other three-decade interval in the last 1,400 years, according to new regional temperature reconstructions covering all seven continents. This period of manmade global warming, which continues today, reversed a natural cooling trend that lasted several hundred years, according to results published in the journal Nature Geoscience by more than 80 scientists from 24 nations analyzing climate data from tree rings, pollen, cave formations, ice cores, lake and ocean sediments, and historical records from around the world.
“This paper tells us what we already knew, except in a better, more comprehensive fashion,” said study co-author Edward Cook, a tree-ring scientist at Lamont-Doherty Earth Observatory who led the Asia reconstruction.
The study also found that Europe’s 2003 heat wave and drought, which killed an estimated 70,000 people, happened during Europe’s hottest summer of the last 2,000 years. “Summer temperatures were intense that year and accompanied by a lack of rain and very dry soil conditions over much of Europe,” said study co-author Jason Smerdon, a climate scientist at Lamont-Doherty and one of the lead contributors to the Europe reconstruction. Though summer 2003 set a record for Europe, global warming was only one of the factors that contributed to the temperature conditions that summer, he said.
The study is the latest to show that the Medieval Warm Period, from about 950 to 1250, may not have been global, and may not have happened at the same time in places that did grow warmer. While parts of Europe and North America were fairly warm between 950 and 1250, South America stayed relatively cold, the study says. Some people have argued that the natural warming that occurred during the medieval ages is happening today, and that humans are not responsible for modern day global warming. Scientists are nearly unanimous in their disagreement “If we went into another Medieval Warm Period again that extra warmth would be added on top of warming from greenhouse gases,” said Cook.
Temperatures varied less between continents in the same hemisphere than between hemispheres. “Distinctive periods, such as the Medieval Warm Period or the Little Ice Age stand out, but do not show a globally uniform pattern,” said co-author Heinz Wanner, a scientist at the University of Bern, in a press release. By 1500, temperatures dropped below the long-term average everywhere, though colder temperatures emerged several decades earlier in the Arctic, Europe and Asia.
The most consistent trend across all regions in the last 2,000 years was a long-term cooling, likely caused by a rise in volcanic activity, decrease in solar irradiance, changes in land-surface vegetation, and slow variations in Earth’s orbit. With the exception of Antarctica, cooling tapered off at the end of the 19th century, with the onset of industrialization. Cooler 30-year periods between 830 and 1910 were particularly pronounced during weak solar activity and strong tropical volcanic eruptions. Both phenomena often occurred simultaneously and led to a drop in the average temperature during five distinct 30- to 90-year intervals between 1251 and 1820. Warming in the 20th century was on average twice as large in the northern continents as it was in the Southern Hemisphere. During the past 2000 years, some regions experienced warmer 30-year intervals than during the late 20th century. For example, in Europe the years between 21 and 80 AD were likely warmer than the period 1971-2000.
The study involved the collaboration of researchers in China, Pakistan, India, Russia and the U.S., among others, under the auspices of the International Geosphere-Biosphere Programme. The project, Past Global Changes 2k Network, or PAGES 2k Network, was funded by the U.S. and Swiss National Science Foundations and the National Oceanic and Atmospheric Administration. The data compiled in the study will be made public and incorporated into the 2013-2014 climate report by the Intergovernmental Panel on Climate Change.
==============================================================
Source: http://www.earth.columbia.edu/articles/view/3081
But there’s no Title, no DOI, no citation to the paper of any kind. And the graphic is absurd.
Sloppy really. A press release should at least NAME THE PAPER.
UPDATE: After prodding the press release writers, they provided a link to the paper.
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1797.html
Continental-scale temperature variability during the past two millennia
Nature Geoscience (2013) doi:10.1038/ngeo1797 Received 09 December 2012 Accepted 11 March 2013Published online 21 April 2013
Abstract
Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
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“Fueled by industrial greenhouse gas emissions, Earth’s climate warmed more between 1971 and 2000 than during any other three-decade interval in the last 1,400 years”
Fail in the first sentence. Global average went up by 0.8 deg C between 1910-1945 according to HadCRUT4: http://www.woodfortrees.org/plot/hadcrut3vgl/from:1910/to:1945
It went up by half during the three decades 1975-2005 (per RSS/UAH)
http://www.woodfortrees.org/plot/rss/to:2003/plot/uah/to:2003
How is it possible, that a scientific article is started with an open lie? Utterly unbelievable. Tar and feather!
Citation number 52 in their Supplementary Information is … wait for it …
the withdrawn Gergis et al paper!
http://www.nature.com/ngeo/journal/vaop/ncurrent/extref/ngeo1797-s1.pdf
Note to authors – if you don’t pay attention to detail, others will.
Slightly O/T
Many readers will recall that warmists have of late been suggesting that the reduced Arctic Ice coverage has played a role in Northern Europe (particularly the UK) experiencing colder than usual winters and snowier than usual winters these past few years. Indeed, one of the regular WUWT commentators (I think it is Steven Mosher) often puts forward this as an explanation as to why more snow is to be expected In Northern Europe whereas previously warmists (in particular Viner) were suggesting that winters would become milder and children would not know what snow is.
The UK Met Office has been looking into this and now considers that there is insufficient evidence to suggest that reducedArctic ice coverage was responsible for the UK’s cold and snowy winter this year. In fact it appears that the Met Office do not consider reduced Arctic ice coverage to be responsible.See http://www.thegwpf.org/met-office-admits-arctic-sea-ice-cold-winter/
MattN,
Could you cite some reputable sources for this claim? My immediate questions are;
1) Are the ice core records homogenous?
2) How do they overcome the difference between regional and global? Regional rates of change/temperature amplitudes are always faster/greater than global.
Thanks in advance.
I guess if everyone agreed on past temps this might not be necessary, but there’s a clamour from certain quarters that the proxy reconstructions are unreliable. Perhaps if you got these people to pipe down, the question could be swept under the carpet and less money spent on it.
But seriously, this study furthers understanding on regional climate, regardless of it not overturning understanding of global climate changes.
Chuck Nolan,
No, Chuck. The bolded bit is what you said. The non-bolded bit is what the article said.
barry,
The entire debate is over global warming. Regional fluctuations are, well… regional.
Because global warming has stopped, the warmists have lost the argument. Mother Earth is the final arbiter.
dbstealey,
The ‘debate’ between some people is about global warming, but that is no reason to reject regional studies. Just because some people don’t get the distinction, doesn’t mean one component should be abandoned. Bob Tisadale, for example, has no problem examining regional climate variation/fluctuation.
wattsupwiththat.com/2013/04/23/a-quick-comment-about-the-pages-continental-temperature-reconstructions/
By ‘global’, do you mean only surface temperatures? Because the oceans have been warming in the time surface temperatures appear to have been flatlining (since 1996, 1998, or 2000).
http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
The full ‘global’ temperature budget goes much further than surface temps.
barry:
By “global”, I mean that global temperatures have stopped rising. Thus, the Warmist crowd has ipso facto lost the debate.
As anyone can see, “carbon” does not cause global warming!
If you give me the opportunity, I can hit you over the head with that fact every day. But wouldn’t it be easier on you to simply admit that CO2≠AGW??
So please, don’t be hypocritical; the science is every bit as settled as the warmist crowd would eagerly claim, if the situation were reversed. CO2 does not cause any measurable global warming. Case closed. As Algore would say: the science is settled. ☺
dbstealey,
I see from your chart that you think that temperatures have flattened since 1997.
That is the case using one metric from only one source. All the other surface/lower troposphere data sets show warming, albeit moderate.
But your chart is not global at all. It doesn’t include the oceans beneath the surface, it does not include heat energy gone into ice melt, and it does not include some of the North and South pole.
By my reckoning, the oceans have heated up since 1997, Greenland has lost ice, 85% of glaciers worldwide have retreated (which would absorb some of the surface heat energy), and Arctic sea ice decline has been much greater than Aantarctic growth.
Adding up, it sure doesn’t look like global warming has stopped since 1997. You can only claim that by isolating one data set representing one portion of the global energy budget. Not remotely convincing, sorry.
barry sez:
“That is the case using one metric from only one source. All the other surface/lower troposphere data sets show warming, albeit moderate.”
barry is delusional. Eight trend lines — all showing the same lack of global warming.
barry has totally lost the argument, but his incurable cognitive dissonance does not allow him to recognize that obvious fact.
dbstealey says:
April 23, 2013 at 9:47 pm
/////////////////////////////////////////
When responding to barry, you could have pointed out the following::
There is no first order correlation between CO2 levels and temperature in the thermometer record, viz
1852 to 1862 cooling, no significant change in CO2 levels (certainlyCO2 was not falling)
1862 to 1878 warming, no significant change in CO2 levels
1978 to 1894 cooling, no significant change in CO2 levels (certainly CO2 was not falling)
1994 to 1902 warming, no significant change in CO2 levels
1902 to 1912 cooling, no significant change in CO2 levels (certainly CO2 not falling)
1912 to 1942 warming, only slight change in CO2 levels, which IPCC acknowledges is not sufficient to explain the warming.
1942 to 1956 cooling, significant rise in CO2 levels yet temperatures fell, ie., anti-correlation.
1956/7 El Nino spike
1957 to 1976/7 cooling, significant rise in CO2 levels yet temperatures fell, ie., anti-correlation.
1956/7
1977 to 1998 warming.significant rise in CO2 lebvels and the only period in the thermometer record where temperatures and CO2 rise in tandem. Howver rate of change is not significantly different to the 1912 to 1942 warming, which suggests that CO2 did not add to the natural variation that was responsible for the 1912 to 1942 warming..
1998 to date, no significant change in temperature although significant rise in CO2.
In summary, there is only one period of about 20 years when temperature anomaly and CO2 levels rise in tandem. However, warmist would have one believe that a 20 year period is too short to be of significance! And in any event, the rate of warming was not significantly different to the 30 year warming between 1912 and 1942 which warming was not caused by CO2 (as acknowledged by the IPCC).
Further, it is not clear whether there was any real warming between 1979 and 1997 since according tom satellite data the temperature was flat, The most obvious explanation for the difference between the thermometer record and that of the satellite measurements is that the thermometer record became polluted by UHI (or local heat island) and/or corrupted by inappropriate adjustments. I emphasise that it may well be the case that there was little if any real warming post 1977 and the observed warming in the thermometer record may (or may largely) be nothing more than poor data collection and/or management.
If one looks at the satellite data there is no first order correlation between CO2 and temperature for the entire 33 year period of the data set, ie., as from 1979 to date. The temperatures are flat between 1979 and about 1997/8, and falt between 1999 to date. There is merely a step change in and around the super El Nino of 1998 and unless that El Nino was caused by CO2, there is no first order correlation and CO2 levels in the satellite data set. As far as I am aware, no one suggests that the super El Nino was the product oof increased CO2 levels in the atmosphere.
Not only is there no first order correlation between CO2 and temperatures in the thermometer record, I would suggest that the same is so of the paleo record. In that record, there are periods not simply when CO2 levels are low but temperatures are high, and periods when temperatures are high when CO2 levels are low (which raises inconsistencies with the GHE conjecture), but more importanatly there are a number of periods when there is anti-correlation, ie., CO2 levels are falling but temperature is increasing, or CO2 levels are rising but temperatures are falling. Whilst correlation does not mean causation, anti-correlation is potentally fatal to a claim of causation. Of course, there are a number of periods where there are similarities between CO2 levels and temperatures, but it appears that temperature lead CO2 and that CO2 is levels (during such periods) is a response not a driver. Of course, one has to view paleo records with a degree of caution since all proxy reconstructions contain significant uncertainties and error bars.
i would suggest that it is one of the greatest PR coups of all time that the public have been led to believe that there is some correlation between CO2 levels and temperature. There is no firsst order correlation, and one needs fudge factors to build any case that there may be some relationship.
Presently, the evidence is strongly suggesting that the climate sensitivity at this period of the Holocene to CO2 is zero or so close to zero that we cannot measure any signal within the tolerance of the data sets that we possess. We cannot weed out the signal to CO2 (if any) from the noise of natural variation.
As regards the oceans, there is no reliable evidence of a change in heat content: we simply do not have the required coverage to make any reasonable assessment in that regard. We would need to increase ARGO coverage well over a million fold. We would need ARGO buoys no more than 50 miles apart and we would need that data set spanning a period of at least 60 years and preferrably 150 years before we could ascertain trends and seperate temperature fluctuations from natural ocean cycles. Any assertion that ocean heat content is increasing is not a scientific assertion, quite simply because we do not possess the data to make any scientific assessment in that regard.
You changed the time period for most of those to give you the result you want. Here are the eight data sets with the same common period that you first introduced – from 1997. As I said, only one fails to show warming, the others are moderate increases.
Tsk tsk. Why did you cherry-pick your start dates instead of comparing apples with apples. Could it be to create a certain impression? Two can play at that game.
Wow, warming has resumed at an incredible rate since 2008!
No cherry-picking here. All the data sets begin at the same time! :-p
(Note: I wouldn’t be so daft as to claim anything about global climate change based on such a short period. Neither should you)
But it doesn’t matter if you start at 1997 or 2000 or in between: Global ocean heat content has risen markedly in these time periods, so global warming has not stopped, just the surface warming has slowed down/stalled.
Roger Pielke Snr vouches that the oceans are the best thermometer for global temps. You think he’s wrong?
Or do you think the global oceans are not a part of the globe?
richard verney,
Did someone say that CO2 was the only climate driver, or that short-term fluctuations would not occur under CO2 warming?
That is your tacit assumption. It is a straw man.
Here are some statistical analyses of CO2/temp correlation, which more properly look at the long-term.
http://residualanalysis.blogspot.com.au/2009/12/statistical-proof-of-anthropogenic.html
http://moregrumbinescience.blogspot.com.au/2009/03/does-co2-correlate-with-temperature.html
Of course we don’t expect a monotonic, lock-strep increase in temps with CO2 forcing. That argument is a fabricated construct. What, the weather, ENSO and other forcings will magically cease to operate while human industry emits CO2 into the atmosphere? Pshaw!
richard verney,
I plotted the two periods either side of 1998, using the amalgamated WFT data set and notice that both periods show moderate warming, not flat trends. I ommitted 1998 data, as you rightly point out that it is a super el Nino, and as it lies at the ends of the time periods, would skew the results based on one year’s major fluctuation.
Now, the super el Nino can’t be responsible for the higher temperatures 1999 to 2013, as el Nino effects fade within months. El Nino is an internal, fluctuating part of the climate system, not a forcing, so something else is responsible for the period 1999 – 2013 being warmer than 1979 – 1997 (Dec).
Oooh, Columbia. Did they get unrepentant terrorist and adjuct professor Kathy Boudin as a co-author?
Sorry, my previous post was Weathermen, not climate. Mea culpa. Also, let me clear up something else: as far as I know, there is no truth to the scurrilous rumor Columbia University has requested Dzokhar Tsarnaev’s transcripts and curriculum vitae
“Fueled by industrial greenhouse gas emissions, Earth’s climate warmed more between 1971 and 2000 than during any other three-decade interval in the last 1,400 years,”
Is the 1971 – 2000 warming based on proxies, raw temperature data, or Hansen’s adjustments? (Hide the decline!)
barry:
At April 24, 2013 at 12:02 am you write
I shall ignore the blatant cherry pick of excluding the El Nino but not the La Ninas on either side of it. But I point out to you that this exclusion alone invalidates your method. ENSO is part of reality: all of it is, not only El Nino. However, instead of rubbishing the method of your “analysis” (OK, I know, but I don’t know what else to call it), I have a question.
Data, dear boy, data. What was it? To be precise, please state the following
Which of the several data sets you used; i.e. RSS, UAH, HadCRUTx, GISS.
The magnitude of “moderate warming” in each period.
The significance of the “moderate warming” in each period; i.e. its discernible difference from zero at what confidence.
Until you can explain these matters your post will remain as being meaningless nonsense only fit for posting on SkS.
Richard