From the University of Hawai’i’s International Pacific Research Center at Mānoa, comes this proxy reconstruction that does some similar things the infamous hockey stick reconstruction, but doesn’t need to pull any statistical “tricks” to make the case. Our old friend the Bristlecone pine in the southwest USA is the test subject again. Like Mann et al, they combined the recent instrumental record of ENSO variation with the proxy reconstruction record, except they didn’t need to delete any data, nor cover up any curves that didn’t behave as they wished. “Mike’s nature trick” wasn’t needed.
Why? Well it has to do with the Bristlecone pine being a better proxy for precipitation than temperature, and as we know, El Niño gives some significant precipitation impacts to the desert southwest. I’ve covered the issue of “treemometers” here and here previously, and they are worth a read as a refresher for this new paper.
They write:
During El Niño, the unusually warm surface temperatures in the eastern Pacific lead to changes in the atmospheric circulation, causing unusually wetter winters in the US Southwest, and thus wider tree rings; unusually cold eastern Pacific temperatures during La Niña lead to drought and narrower rings.
Liebig’s Law in a nutshell. In a desert, water is the limiting factor for growth, temperature, not so much. So I’m inclined to trust this reconstruction a bit more than I’d trust Mann’s. The test will be when somebody asks for the data for replication purposes.
Tree Rings Tell a 1100-Year History of El Niño
El Niño and its partner La Niña, the warm and cold phases in the eastern half of the tropical Pacific, play havoc with climate worldwide. Predicting El Niño events more than several months ahead is now routine, but predicting how it will change in a warming world has been hampered by the short instrumental record. An international team of climate scientists has now shown that annually resolved tree-ring records from North America, particularly from the US Southwest, give a continuous representation of the intensity of El Niño events over the past 1100 years and can be used to improve El Niño prediction in climate models. The study, spearheaded by Jinbao Li, International Pacific Research Center, University of Hawai’i at Manoa, is published in the May 6 issue of Nature Climate Change.
Tree rings in the US Southwest, the team found, agree well with the 150-year instrumental sea surface temperature records in the tropical Pacific. During El Niño, the unusually warm surface temperatures in the eastern Pacific lead to changes in the atmospheric circulation, causing unusually wetter winters in the US Southwest, and thus wider tree rings; unusually cold eastern Pacific temperatures during La Niña lead to drought and narrower rings. The tree-ring records, furthermore, match well existing reconstructions of the El Niño-Southern Oscillation and correlate highly, for instance, with δ18O isotope concentrations of both living corals and corals that lived hundreds of years ago around Palmyra in the central Pacific.
“Our work revealed that the towering trees on the mountain slopes of the US Southwest and the colorful corals in the tropical Pacific both listen to the music of El Niño, which shows its signature in their yearly growth rings,” explains Li. “The coral records, however, are brief, whereas the tree-ring records from North America supply us with a continuous El Niño record reaching back 1100 years.”
The tree rings reveal that the intensity of El Niño has been highly variable, with decades of strong El Niño events and decades of little activity. The weakest El Niño activity happened during the Medieval Climate Anomaly in the 11th century, whereas the strongest activity has been since the 18th century.
These different periods of El Niño activity are related to long-term changes in Pacific climate. Cores taken from lake sediments in the Galapagos Islands, northern Yucatan, and the Pacific Northwest reveal that the eastern–central tropical Pacific climate swings between warm and cool phases, each lasting from 50 to 90 years. During warm phases, El Niño and La Niña events were more intense than usual. During cool phases, they deviated little from the long-term average as, for instance, during the Medieval Climate Anomaly when the eastern tropical Pacific was cool.
“Since El Niño causes climate extremes around the world, it is important to know how it will change with global warming,” says co-author Shang-Ping Xie. “Current models diverge in their projections of its future behavior, with some showing an increase in amplitude, some no change, and some even a decrease. Our tree-ring data offer key observational benchmarks for evaluating and perfecting climate models and their predictions of the El Niño-Southern Oscillation under global warming.”
This research was funded by the National Science Foundation, National Oceanic and Atmospheric Administration, Japan Agency for Marine-Earth Science and Technology, National Basic Research Program of China, and the National Natural Science Foundation of China.
Citation: Jinbao Li, Shang-Ping Xie, Edward R. Cook, Gang Huang, Rosanne D’Arrigo, Fei Liu, Jian Ma, and Xiao-Tong Zheng, 2011: Interdecadal modulation of El Niño amplitude during the past millennium. Nature Climate Change.
Source here (PDF)
“No, as the sunspot number is overestimated since 1945.”
Enough to wipe out any further upward trend in the averaged slope since 1780? Due to all the ‘revisions’ of solar science that are going on you will need to forgive me if I keep an open mind.
“The particles [unvarying chemistry] follow the radiation except deliver six orders of magnitude less energy, so radiation is the driver, if anything.”
The delivery of energy is not the issue. The number of chemical reactions they cause is so it is particle numbers that matter not particle chemistry or energy levels. Furthermore the variations in UV and EUV appear to be a larger factor. We can agree that radiative physics does not account for the observations but it is looking very likely that chemical processes do.
Hmmm, there’s something Belousov-Zhabotinskii about all this, not so much in the propagation of chemical reactions, but in the alternating albedo.
Leif, I don’t see the circularity as lethal; a stable system may have circular excursions, and I still think a workaround for the hypersensitivity is suggested.
Also, moshe, there may well be more mechanisms involved than I or anyone can imagine.
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OK, even I don’t know what ‘a stable system may have circular excursions’ means.
Oh well there’s always haiku:
Erl Happenstances,
Behold the bright and fair child.
Mysterious blonde.
And my fave:
The sun is very sultry and we must avoid its ultry-violet rays.
H/t to Plum & NC.
======================
People love simple answers. That is, people who aren’t looking for anything except a simple answer love simple answers.
Bob Tisdale:
I haven’t ignored your other graphs. I know that there are multidecadal swings between El Nino and La Nina but if one smooths the anomaly over the whole period as you did then the flat line shows that on average over the entire period the size of the anomaly in favour of El Nino has been the same.
Perhaps it is my use of the word ‘constant’ that you found to be unclear. Obviously there is no constancy on the shorter timescale but constancy does seem to be present on the longer timescale hence the flat line.
Stephen Wilde says: “I know that there are multidecadal swings between El Nino and La Nina but if one smooths the anomaly over the whole period as you did then the flat line shows that on average over the entire period the size of the anomaly in favour of El Nino has been the same.”
If you are averaging over the whole term of the data, then the answer would depend on the period of your base years for anomalies. If your base years were the entire term of the data (from 1900 to present), then the average would be zero.
Pascvaks says:
May 8, 2011 at 7:24 am
People love simple answers. That is, people who aren’t looking for anything except a simple answer love simple answers.
Every complicated problem has a simple solution, that is wrong.
Bob,
The average anomaly is not zero because El Nino clearly dominates over La Nina.
http://i43.tinypic.com/33agh3c.jpg
However the size of the anomaly does not change when averaged over the period:
http://i56.tinypic.com/2ag0u2u.jpg”
I consider this to be important because it shows that the cause of the 20th century warming of the troposphere is oceanic and the rate of change has not varied since at least 1900 which is before the proposed impact of human sourced CO2.
So the next sep is to then ascertain why the 20th century El Nino dominance arose in the first place and at that point I would introduce my proposition that the level of solar activity had been increasing thereby shifting the jets to decrease cloudiness and albedo thereby providing more fuel for the 20th century bias in favour of El Nino.
In fact I think the 20th century scenario is just an extension of what has been happening since the Maunder Minimum.
Stephen Wilde says:
May 8, 2011 at 10:39 am
I would introduce my proposition that the level of solar activity had been increasing thereby shifting the jets to decrease cloudiness and albedo thereby providing more fuel for the 20th century bias in favour of El Nino.
Figures 10 and 14 of http://www.leif.org/research/2009JA015069.pdf show that there has been no increase in solar activity the past 300 years.
Leif,
There have been changes in the mix of wavelengths and particles have there not?
Also the assertion that there has been NO increase in solar activity the past 300 years seems somewhat surprising. Do you completely discount the apparently high activity levels of the late 20th century?
Anyway you said:
“Solar activity in the 1780s was probably higher than in the latter part of the 20th century.”
That is only 230 years ago. Do you say there was no increase during the 70 years up to the 1780s?
Is it your contention that by 1700 there was a full recovery from the Maunder Minimum with no further increase in solar activity since then?
Stephen Wilde says: “The average anomaly is not zero because El Nino clearly dominates over La Nina.”
Again, it depends on the base years.
1950 to 1979 as base years:
http://i53.tinypic.com/scfkmb.jpg
1900 to 2010 as base years:
http://i51.tinypic.com/2mnizhk.jpg
Stephen Wilde says:
May 8, 2011 at 3:31 pm
There have been changes in the mix of wavelengths and particles have there not?
There are changes from day to day. Tiny and involving very little energy.
Also the assertion that there has been NO increase in solar activity the past 300 years seems somewhat surprising. Do you completely discount the apparently high activity levels of the late 20th century?
Educate yourself. Start by studying Figures 10 and 14 of http://www.leif.org/research/2009JA015069.pdf that show that there has been no increase in solar activity the past 300 years. Also read the last eight lines of paragraph [28]. Tell us what you get out of this.
As a Californian, I’m pleased that the noble Bristlecone Pines in our Eastern mountains, and in other parts of the Basin and Range Region, are once again being used for legitimate scientific purposes.
sceptical says:
May 7, 2011 at 10:02 pm
If a man comes in trolling, he’s not interested in debating the science. I was pointing that out.
w.
Chladni patterns from Climate Audit:
http://climateaudit.org/2011/05/08/nature-publishes-another-chladni-pattern/
See also CA: buell castles in the clouds, which references On the physical interpretation of Empirical Orthogonal Functions by C. Eugene Buell
From a comment by Michael J:
From a comment by Steve McIntyre quoting on offline comment:
Like I said boys. Avoid the BCP
funny to watch people exercise selective skepticism
Wilde is the silliest of all.
The results are Chladni patterns.
ha. the sun predicts chladni patterns.
thats rich.
nostradamus strikes again
Leif Svalgaard said:
“Educate yourself. Start by studying Figures 10 and 14 of http://www.leif.org/research/2009JA015069.pdf that show that there has been no increase in solar activity the past 300 years. Also read the last eight lines of paragraph [28]. Tell us what you get out of this.”
What I get out of the entire paper (and many others) is that the proper interpretation of many aspects of the effects of solar variability on the components of the Earth system is very much an ongoing and so far inconclusive work with many disagreements and discrepancies.
In so far as there is some convergence occurring between the differing interpretations it is hard to tell whether that represents a real truth or just a wider sharing of similar initial assumptions.
The trouble is that the closer you all get to discounting any significant solar variability the more troubling is the apparent discrepancy between that finding and observed events out in the real world. Those observations suggest to the rest of us that some hithero underappreciated component of solar variability has an effect on the Earth’s energy budget.
So please forgive me for relegating all your work to an interesting but inconclusive set of solar data which appears to be largely off the target as regards solar involvement in climate.
Bob Tisdale says:
May 8, 2011 at 6:12 pm
Ok, I can see that the size of the anomaly averaged over the whole period varies a bit depending on the base period.
So my observation that the anomaly remains constant throughout the period was somewhat trite.
However what I can draw from it is the absence of a negative anomaly whatever base period you select.
Thus for the whole of the period from 1900 to 2010 the anomaly was positive to some degree or another depending on the base periods chosen and that provides a cause of troposheric warming over the period leaving the cause of that persistent positive anomaly open to debate.
What would be most interesting would be to see whether the anomaly was ever negative for any significant period of time going back to the Maunder Minmum.
Can your data help with that?
steven mosher says:
May 9, 2011 at 12:33 am
Like I said boys. Avoid the BCP
funny to watch people exercise selective skepticism
Wilde is the silliest of all.
That seems a bit harsh.
Bob Tisdale:
Of course you could produce a negative anomaly for portions of the 1900 to 2010 time period but as you know my interest is in the average net anomalies over long time periods such MWP to LIA and LIA to date.
Just a note: Li et al 2011 is not the only ENSO reconstruction. It is, however, longer than Stahl et al (1998) and Mann et al (2000). Refer to the post:
http://bobtisdale.wordpress.com/2009/03/13/low-frequency-enso-oscillations/
Tree rings are a laugh. They are sensitive to temperature like this:
winter temps never go below freezing – tropical plants flourish (as they do in the south coast of the UK)
winter temps go slightly below freezing – deciduous trees flourish (as they do in England)
winter temps go a long way below freezing – coniferous trees flourish (as they do in Scotland and Germany and mountainous regions of the Southern Med as well as Scandinavia).
I don’t see them being any more sensitive than that. Its just about whether they are adapted to cope with the water in their cells freezing and little more. After that its the rain and the sun that matters. Most plants in the UK grow like crazy in the Spring when its sunny and wet and the chlorophyll can work its wonders. Its not particularly warm though.
steven mosher says:
May 9, 2011 at 12:33 am
Steve, I think you have misread my contribution here. I have no particular brief in favour of BCP data. I just took what was presented and pointed out a specific feature of the data supplied.
Subsequently I have been engaged with Bob and Leif on separate (though related) issues because they are highly expert on solar and ENSO issues and if I am to develop my own (non BCP) ideas then I have to deal with their objections first.
I am often wrong on specific points and have accepted corrections but I don’t think my general overview is wrong (so far).
Is that ‘silly’ ?
“Bob Tisdale says:
May 9, 2011 at 1:53 am
Just a note: Li et al 2011 is not the only ENSO reconstruction. It is, however, longer than Stahl et al (1998) and Mann et al (2000). Refer to the post:
http://bobtisdale.wordpress.com/2009/03/13/low-frequency-enso-oscillations/”
Thank you Bob. That is interesting.
Li’s paper shows about 400 years of stronger El Nino since 1600 whereas Stahl and Mann show 350 years of weaker El Nino since about 1650.
Any idea how to resolve that ?
For AGW purposes Stahl and Mann’s decline would be preferred so as to minimise oceanic effects as the cause of tropospheric warming since the industrial revolution.
If we go by Li’s reconstruction (whatever we think of BCP data) oceanic effects remain a prime candidate as the cause of the observed tropospheric warming.