The Detection of Climate Regime Transitions in the Upper Colorado River Basin

 Guest essay by Samuel I Outcalt

Introduction: Several global climate regime transitions are well documented. These transitions are listed in Table 1.

outcalt-table1 The Treeflow Records at Lees Ferry, Arizona and Cisco Utah: Treeflow records are constructed using the parameters derived by the regression analysis of modern tree ring and stream discharge data. Lees Ferry is located just downstream from the Glen Canyon Dam, which formed Lake Powell. Dam construction began in 1960. The Treeflow parameters were calculated to allow for the altered flow produced by the dam. The Treeflow record at Lees Ferry is displayed as Figure 1.



Figure 1. The Normalized Treeflow Data at Lees Ferry, Arizona.

In Figure 1 regime transitions are detected by inflections in the integral trace (cumulative deviations from the record mean). Note that all of the regime transitions listed in Table 1 were detected. This method is described in a recent paper (Outcalt The latter part of this record is presented as Figure 2.



Figure 2. The Treeflow Record from 1800 to 2002.

Note that all of the modern regime transitions from Table 1 were detected. To validate the transitions detected in Figure 2 the modern discharge record on the Colorado River near Cisco, Utah is displayed as Figure 3.



Figure 3. The modern Treeflow record and integral trace near Cisco, Utah (185 miles North East of Lees Ferry, Arizona).


In Figure 3 all the modern regime transitions from Lees Ferry were detected.

Conclusion: All of the major climate regime transitions from the Onset of the Medieval Warm Period to the End of the Modern Warm Regime are detectable in the Treeflow and Modern Discharge Data for the Upper Colorado Basin using the Hurst ReScaleing technique.



Outcalt,S.I., Hinkel, K.M.,Meyer,E . and Brazel,A.J.(1997) The application of Hurst Rescaling to serial geophysical data. Geographical Analysis 29, 72-87.

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April 13, 2015 3:18 pm

lt looks like the Medieval warm period was not quite so warm around 1190.

Joel O’Bryan
Reply to  taxed
April 13, 2015 3:51 pm

Around 1120-1150 AD, the Anasazi Pueblo indians at Mesa Verde National Park (MVNP) moved their partially buried Kiva-type dwellings off the mesa top and built the hundreds of large south-facing pueblo cliffside structures that are still preserved to this day at MVNP.
It has been suggested by several archaeologists that the likely reason they moved down from the mesa top were the winters were getting too cold on the mesa top itself, and the south facing pueblos offered better warmth and protection, while they also moved their fields to the lowest parts of the mesa.
There are still hundreds of these cliff side dwellings along the canyon walls at MVNP, but the Anasazi only occupied them for about 150 years before they were all abandoned around 1275 AD and the Anasazi culture completely collapsed and the people dispersed to the south to lower elevations.

Reply to  Joel O’Bryan
April 13, 2015 5:51 pm

I thought it was the increasing frequency and duration of drought.

Reply to  Joel O’Bryan
April 14, 2015 12:24 am

Trafamadore – there are now considerably more than three times as many people in England compared to 1000 AD. English sparkling wines are among the best in the world, bar none; look at recent competition results. Modern English vineyards are almost all in the south of the country. What you say is, as usual, uninformed.

Reply to  Joel O’Bryan
April 14, 2015 1:59 pm

I’ve visited the Chaco Canyon sites more than once (The Mesa Verde structures were built by Chacoan satellite populations) and have always been struck by how their signature construction was the large, “D” shaped apartment structure, with the flat side of the “D” and its open plaza always facing due south. The obvious logical reason is that they were trying to maximize whatever winter light and warmth they could capture in their public spaces, and the fact that they organized all of their important constructions around this principle tells us it was something they put a great deal of thought and effort into.

Patrick Bols
Reply to  taxed
April 13, 2015 3:54 pm

Not so warm? Maybe. And yet there were vineyards in England.

Reply to  Patrick Bols
April 13, 2015 5:43 pm

Maybe Oceanic oscillation had something to do with that?

Reply to  Patrick Bols
April 13, 2015 5:48 pm

There are vineyards now in England, about 3 times as many as in 1000 AD England. England’s biggest problem is that for the most part they don’t drink wine as much as beer.
What I say is, when in England don’t drink the wine; when in France don’t drink the beer, and when in Mexico don’t drink the water.

Reply to  Patrick Bols
April 13, 2015 6:06 pm

I think the data tell us that it was cold and/or dry during the minimum, if I understand tree ring analysis as well as I (interested but uninformed) think I do.

Reply to  Patrick Bols
April 14, 2015 12:10 am

Trafamadore – there are considerably more than three times as many people in England than there were in 1000 AD. English sparkling wines are rated among the best in the world, bar none, but AFAIK they’re all produced in the south of the country. I’m told there were vineyards as far north as York 1000 years ago.

Reply to  Patrick Bols
April 14, 2015 10:41 am

trafamadore: You are comparing apples and grapes.
Modern grape vines have been bred over the last 1000 years to be more tolerant of climate extremes.

Reply to  taxed
April 14, 2015 1:39 pm

Dam construction began in 1960. The Treeflow parameters were calculated to allow for the altered flow produced by the dam.
A model.
I didn’t see access to the calculations of Treeflow parameters, allowing for the altered flow.
All may be well.
I like the model output – but that bit of it is most certainly a model.
I emphasise – the last fifty years are built on calculations from a model.
…. It may be correct in every detail.

Joel O’Bryan
April 13, 2015 3:28 pm

In Figure 1, the end of the MWP, at 1250 AD, and onset of the LIA, at 1300 AD, both fit in perfectly with the previously dated onset of collapse and final collapse of the Ansazi Pueblo Indians at Mesa Verde, Colorado (MV National Park , MVNP) about 120 miles to the east of Lee’s Ferry.
The National Park Service at MVNP began in 2010 trying to simply play it as likely drought and societal tensions for the collapse. The point is COLD is bad. Cold is drier (drought). The maize they grew on the slopes of the mesa and mesa top require about 73 frost free days-nights to mature, today there are about 83 days on average See photo from one of the placards at Far View reserviour on the mesa top from MVNP
The Anasazi began to occupy and expand on the mesa top around 750-850 CE, and developed more and more complex, interdependent society centered around farming. They expanded from a few hundred to tens of thousands in the 400 years of development. In the final 150 years they occupied mostly south facing large complex multi-story cliff dwellings just down off the higher 8500-7500′ plateau where they farmed their crops of maize with a cistern and irrigation system. It all came crashing down suddenly though. heir society apparently disintegrated in just several years around ~1270-75 CE, with the population dispersing throughout New Mexico, Utah, and Arizona.
However, the current (2013) NPS Mesa Verde NP paper hand-out literature to park visitors says this:

“We know that the last quarter of the A.D. 1200s saw drought and crop failures—but these people had survived earlier droughts. Maybe after hundreds of years of intensive use the land and its resources—soils, forests, and animals—were depleted.”

Note: there is NO mention of a cooling climate now in the MVNP literature. Only of drought , intensive land use, resource depletion. References to a colder climate has been removed in recent years from the paper Mesa Verde NP literature hand-outs.
Climate Change is indeed man-made.

Reply to  Joel O’Bryan
April 14, 2015 1:52 pm

The drought I’ve seen referenced for the southwest in the mid to late 1200’s is based on tree ring data, and supposedly lasted for at least 25 years. One theory is that not only was it hard to live, but the generation long lack of rain destroyed the culture’s faith in its leadership and social systems, and the entire thing just fell apart. Some good evidence suggests they moved on down into New Mexico, with some of their descendants eventually ending up in the Rio Grande Valley.
I think the real point of this is that it is very possible for the Southwest to see a 25 – 30 year drought, since it’s happened several times in the past, and it’s just a part of the cyclical weather cycle. Southern California, anyone?

April 13, 2015 3:33 pm

Are these charts upside down?

Mac the Knife
Reply to  Tom Trevor
April 13, 2015 8:23 pm

Are you suggesting another mann made invention?

April 13, 2015 3:54 pm

So river flow is correlated with…
Well humidity is correlated with air temperature…
Look, is this a meaningful correlation because heat transfer in this region is always predominately due to heat of evaporation or is this just plain luck.
Somewhere the heat transfer will be predominately due to heat of evaporation.
This may be insignificant.

April 13, 2015 3:56 pm

Thanks, Samuel I Outcalt.
I have been comparing this global temperature reconstruction to the other I’ve found:
Always learning.

Reply to  Andres Valencia
April 14, 2015 12:01 am

I compared the same Loehle’s data to changes in the strength of the Arctic geomagnetic field.
The 2000 year long correlation is surprisingly good except for period 1400-1500 (amounts for 5% of the total time) when it flips to negative. After 1650 with the ‘instrumental’ records R2=0.84

April 13, 2015 4:00 pm

According to the source of the Spencer graphic:
This graph shows the average of 18 non-tree ring proxies of temperature from 12 locations around the Northern Hemisphere, published by Craig Loehle in 2007, and later revised in 2008. It clearly shows that natural climate variability happens, and these proxies coincide with known events in human history.
Loehle also published in 2008 a paper that described why tree rings can not be trusted as a proxy for past temperature variations. Tree ring data have what is called a “divergence problem” in the late 20th Century where the tree ring data data suggests cooling, when in fact there has been warming. This, by itself, should cast serious doubt on whether tree ring reconstructions (such as Michael Mann’s famous “hockey stick” curve) can be used to estimate past global temperature variability.

April 13, 2015 4:36 pm

This essay has nothing of value to contribute to anything:
– What of all the other peaks and troughs in Figure 1, that go counter to specified Warm Periods and Ice Ages?
– You CAN NOT pick and choose the specific times on the charts to fit explanations like Warm Period and Ice Age, when MOST of the chart is inconsistent with your chosen points of reference.
This is well backed up with the poor understanding that people have with statistical analysis and physical system analysis. Most if not all people in the dendroclimatic research area, use linear models or understand for complex systems, and that is a big mistake, as I quite clearly point out in my two points above. But if you want a more technical argument I’ll give you one.
The problem is that tree rings or any other dendroclimatic variable is fundamentally nonlinear. This has been well shown in the Divergence Problem in the past 50 years. Now because there is such a possible Divergence between Temperature and “Tree Variable” (specifically, it is shown that tree ring width has shown to trend with higher temperature before 1960 – with hard data correlations of temperature and width – but after 1960, there are large swathes of trees that show no correlation, or worse a negative correlation), thus, it is now IMPOSSIBLE to use calibration curves for temperature vs tree variables, from any period since data has been being collected on temperature and tree ring widths, to give temperatures for the last 1,000 years. In addition, there are many other issues which I will not go into for they are mute cause of this divergence problem, like accounting for tree age and incoming radiation effects.
Tree ring analysis, or any dendroclimatic preoccupation is pure nonsense. This “interest”, its not a science, it has so many analytical and physical problems that it is absolutely pointless to even consider this “interest” that people have in tree data. This is just another example where Science has gone bad, there is NO means to apply the Scientific Method here, absolutely none.
A nice paper to illustrate the basics of what I outlined is illustrated by Loehle, which you can find <a href="; here .
The real problem once again is that so many people poorly understand what they are doing. Loehle, and there are many others, appear to be continually ignored. Well what do you expect, when the only outcome is that Loehle’s arguments will put out of work a lot of people in climatology.
I’m sick of this nonsense. Theoretical Science Fiction (TSF) seems to be the norm these days…you can add this above essay by Outcalt along with all of climatology.

Reply to  Dorian
April 13, 2015 4:42 pm

I was going to ask the same thing. Why are some dips and peaks significant while others that look
larger or just as sharp are not?

Reply to  Dorian
April 13, 2015 6:45 pm

Thanks for the link.

Stephen Wilde
April 13, 2015 4:37 pm

Good to see that the end of the Modern Warm Regime is indicated for 2000.
For the past 8 years I’ve been telling everyone that 2000 was when I first noticed that the jet stream tracks were becoming more meridional again as in the period before 1976.
Obviously nothing whatever to do with our emissions and far more likely to be a result of solar variations affecting the gradient of tropopause height between equator and poles via changes in the stratospheric ozone creation / destruction balance.
Also around 2000:
Stratospheric cooling stopped and warming may be in progress.
Global cloudiness stopped falling and began to increase again.
El Nino events started to lose power relative to La Nina events.
Troposphere warming ceased and cooling may now be in progress.
The ozone hole began a rather fitful decline in size.
The Arctic Oscillation started to become more negative.
Climate zones stopped moving poleward.
Solar activity began its decline towards recent very low levels.
Sea rise rate has slowed.
Looks good for my New Climate Model.

Reply to  Stephen Wilde
April 13, 2015 6:14 pm

Irritating records in the last few years, pass on by, don’t look…

April 13, 2015 4:39 pm

I would put the onset of the modern warming period in 1908 rather than 1975. You have an inflection there and physically it starts to define the grand maximum of current solar activity.

April 13, 2015 5:08 pm

Ummm. Please define “treeflow” and how describe how this data was acquired? How do tree rings correlate to stream discharge data? Or are tree rings used to estimate stream discharge data? A link to the original article would be nice. Or is this article off-line? The charts look interesting, but it’s difficult for me to know what the “normalized axis” is actually measuring.

April 13, 2015 5:16 pm

end of the little ice age….1870
….or around 1980

old construction worker
Reply to  Latitude
April 13, 2015 6:25 pm

I’m with you. Who gets to establish ‘the norm”? The Roman warm period was warmer than the MWP and this so called Modern warm period is cooler than the MWP. Folks, if this was a stock chart I would be shorting the stock.

April 13, 2015 5:30 pm

Wait a minute. The medieval warm period lasted 3+ centuries and our modern warm period lasted 24 years? Am I the only one who feels ripped off? I want at least another 100 years of warming please!

Reply to  TRM
April 13, 2015 6:30 pm

I know, right? I ordered a new mankini and the Amazon drone hasn’t even arrived yet.

Reply to  Max Photon
April 13, 2015 8:12 pm

It would be a tough delivery in this:

Stephen Richards
Reply to  Max Photon
April 14, 2015 12:54 am

April 13, 2015 at 8:12 pm
It would be a tough delivery in this:
Yes but what a great way to be able to maintain the lines. I spent years of my youth repairing those insulators and lines from laccer and safety belt.

April 13, 2015 5:31 pm

Seems that proxy determinations may have some use for determine degree of variability and rates of change. But pretty speculative with respect to temperature-estimates.
Interesting nonetheless.

April 13, 2015 6:01 pm

That sharp dip in the graph around the late 1100’s is interesting. Does it show up in other records dating back this far in other parts of the USA.Or is it just a case of a local weather event, because it looks like the USA was struck by some very cold weather at that time.

James at 48
April 13, 2015 6:31 pm

I’m not quite ready to say the Modern Warm Regime is done, done. But it is definitely shaky.

April 13, 2015 6:32 pm

Why such a wimpy warm period?

April 13, 2015 6:50 pm

I was wondering what ‘treeflow’ means, and found this site: — Streamflow reconstruction from tree rings
(Is there anything tree rings can’t do?)

April 13, 2015 9:56 pm

First, Mr. Outcalt, thank you for your work.
However, you have not published or linked to the data used for the analysis. As a result, what you have presented is not science—it is merely an advertisement for science.
Nor have you detailed the method used to construct the “treeflow” data. And finally, you’ve not detailed how you decided that certain changes in the “integral trace” are important but others are not.
Until all of that is done, it is not possible to assess the strength of the hypothesis you put forward.

April 13, 2015 10:11 pm

Google Search “Treeflow”

April 13, 2015 10:40 pm

Figure 3. Should caption error. This is a modern discharge record.

April 14, 2015 12:08 am

Again the Caption on Figure 3. should read “Modern Stream Discharge”.
WE’s comment is correct as there are other inflections on tree rings and discharge are influenced by factors other than Global Regime Shifts. However, the modern Treeflow transitions in Fig 2 are also present in the upstream modern discharge record at Cisco. The fact that the onset and end of the modern warm regime are detectable in stream discharge data is significant. As the USHCN data has recently been “adjusted” these transitions are no longer detectable in that data. Treeflow and modern stream flow data therefore a valuable resource.
From the author on this note !

April 14, 2015 12:15 am

No data, no method, not even link to a paywalled abstract of his own paper.
A few cherry-picked spikes are arbitrarily attributed to various periods, while other much larger peaks go ignored.
Data has been “corrected” for the construction of a dam?!
If this paper article was signed by M.Mann it be ( rightly ) being ripped to bits.
Standards are dropping at WUWT if this sort of non-scientific rubbish is getting air-time.
Willis says:

…what you have presented is not science—it is merely an advertisement for science.

No, it’s a paradoy of science. A travesty !
Very disappointing.

randy Julander
April 14, 2015 6:21 am

would just like to comment on the last 50 years of flow data on the colorado river. the official adjusted flow for the river includes adjustments for – 17 large reservoirs and 17 large diversions. the reality of the flow is that on the Utah side of the colorado river, there are 485 diversions and 2,220 reservoirs of all size. on the colorado side there are 11,000 reservoirs, lakes and ponds that store water for consumption in some fashion, 33,000 water rights/diversions and 7,000 wells. there are a substantial number in wyoming as well, likley similar to utah. the trend in streamflow is likley correct but i would be very suspicious of the magnitude due to these consumptive uses that are not included in the official adjusted record.

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