From the LOUISIANA STATE UNIVERSITY and the department of tilt-a-whirl, comes this Milankovitch moment.
![milankovitch[1]](https://wattsupwiththat.files.wordpress.com/2015/03/milankovitch1.jpg?resize=720%2C405&quality=83)
LSU paleoclimatologist Kristine DeLong contributed to an international research breakthrough that sheds new light on how the tilt of the Earth affects the world’s heaviest rainbelt. DeLong analyzed data from the past 282,000 years that shows, for the first time, a connection between the Earth’s tilt called obliquity that shifts every 41,000 years, and the movement of a low pressure band of clouds that is the Earth’s largest source of heat and moisture — the Intertropical Convergence Zone, or ITCZ.
“I took the data and put it through a mathematical prism so I could look at the patterns and that’s where we see the obliquity cycle, that 41,000-year cycle. From that, we can go in and look at how it compares to other records,” said DeLong, who is an associate professor in the LSU Department Geography & Anthropology.
With research collaborators at the University of Science and Technology of China and National Taiwan University, DeLong looked at sediment cores from off the coast of Papua New Guinea and stalagtite samples from ancient caves in China. DeLong’s data analysis revealed obliquity in both the paleontological record and computer model data. This research was published inNature Communications on Nov. 25.
The standard assumptions about how the variations in the Earth’s orbit influences changes in climate are called Milankovitch cycles. According to these principles, the Earth’s tilt influenced ice sheet formation during the Ice Ages, the slow wobble that occurs on a 23,000-year cycle as the Earth rotates around the sun called precession affects the Tropics and the shape of the Earth’s orbit that occurs on a 100,000-year cycle controls how much energy the Earth receives.
“This study was interesting in that when we started doing the spectral analysis, the 41,000-year tilt cycle started showing up in the Tropics. That’s not supposed to be there. That’s not what the textbooks tell us,” DeLong said.
This finding shows that the tilt of the Earth plays a much larger part in ITCZ migration than previously thought, which will enable climate scientists to better predict extreme weather events. Historically, the collapse of the Mayan civilization and several Chinese dynasties have been linked to persistent droughts associated with the ITCZ. This new information is critical to understanding global climate and sustainable human socioeconomic development, the researchers said.
Additionally, climate scientists have begun to recognize that rather than shifting north and south, the ITCZ expands and contracts, based on this information.
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“Additionally, climate scientists have begun to recognize that rather than shifting north and south, the ITCZ expands and contracts, based on this information.”
Have begun???
The shrinking or extending of the meteorological equator was demonstrated by Prof. Marcel Leroux in his seminal 1993 paper!!!!
http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf
Figure 11 and Figure 13.
In fact, I think it would be a perfect footnote link to this post.
Thank you.
Here is a much more interesting article and evidence that scientists still have so much more to learn and explore; hopefully no one will be accused of genocide by commenting on it.
http://www.bbc.com/earth/story/20151215-the-most-violent-events-since-the-big-bang-itself
DeLong’s data analysis revealed obliquity in both the paleontological record and computer model data.
How in h*ll did it get programmed into the models before it was discovered?
They have a MODEL for that !! LOL
I thought this stuff died.
Spectral analysis was all the rage in geology at that time. My adviser was one of the big cheerleaders for this research. His opinion changed once he visited Belize to study modern sedimentation in relationship to what he was doing. His research there crushed every assumption he had used in the previous 10 years and destroyed his own dissertation. Around the middle of the last decade, everyone realized what a load of crap it was, and spectral analysis was abandoned because none of the assumptions held up in the real world.
Everyone still believes Milankovitch Cycles has some effect on climate, and that the geological record has some signal in it that shows this. I don’t think anyone knows, however, how to tease it out without unrealistic assumptions.
It sounds like the researchers used spectral analysis. If you all knew some of the insane assumptions behind this, you would be banging your head against a table.
Dear,oh dear ,oh dear !. Throwing around so many assertions with free abandon is not going to solve any of this even when there is an opportunity to model effects by altering the main component behind planetary climate.
Everyone listening –
All planets possess a climate and therefore common traits are used to distinguish one planet from another.
There is a climate spectrum between 0° inclination and a maximum 90° inclination.
0° inclination represents a totally equatorial climate much like the planet Jupiter.
90° inclination is at the other end of the spectrum and represents a totally polar climate much like Uranus.
The Earth,with its 23 1/2° inclination has a largely equatorial climate with a sizable polar input. An increase in inclination towards 90° would introduce polar conditions over a greater surface area of the planet with the same heat budget . The idea of ‘polar’ doesn’t mean colder but rather greater swings between summer and winter with less Spring and Fall conditions.
There is no audience for this measured approach at the moment but eventually observers will come around to the narrative which re-introduces climate to a wider audience by expanding perspectives to include all planets.
I tried to follow the analysis, but their seemingly deliberate obfuscations lost me. For example:
Neodymium isotopic compositions were measured by a multi-collector ICP-MS, Thermo Fisher Neptune, in the HISPEC. The measured 143Nd/144Nd ratios were normalized to 146Nd/144Nd=0.7219 using an exponential law. La Jolla standard was measured at 0.511811±0.000014 (or ±0.27 ε; 2σ, n=13). All 143Nd/144Nd ratios were calibrated to the reported value relative to the La Jolla standard value of 0.511858 (ref. 57). Sample 143Nd/144Nd ratios [(143Nd/144Nd)sample] are expressed as ε notation defined by an equation of εNd=[(143Nd/144Nd)sample/(143Nd/144Nd)CHUR−1] × 104, where the 143Nd/144Nd ratio of CHUR standard for Chondritic Uniform Reservoir [(143Nd/144Nd)CHUR] is 0.512638
They claim accuracy of 0.511811±0.000014, which I find questionable. And looking at their images of before and after artist drawings…
http://www.nature.com/ncomms/2015/151125/ncomms10018/images_article/ncomms10018-f4.jpg
…makes me wonder what the big deal is.
And:
At low obliquity, the ‘pressure-push’ forcing, strengthened by the capacious Asian landmass, is weak and the northerly wind intensity and ITCZ shift tends to follow precession-dominated insolation. The peak northerly wind and Australian low occur at high precession (~20, 70, 115, 185 and 230 kyr BP; Supplementary Fig. 8). However, these precession-induced changes are not more vigorous than ones at intervals with high obliquity…
The forcing is the same at both high and low obliquity? I wonder how much time they spent finding that out?
If I were a peer review referee, I’d probably pass this because while it seems pretty pointless, maybe there’s a grain of value in it. Or not. But who can really tell?
The way to find out is with predictions. If they’re repeatable and correct, there is value. But I don’t see any predictions here.
I predict that in 10,000 years this study will be just as meaningless as it is today !!
” mathematical prism ” is as concise and elegant a description of a Fourier analysis as I have ever seen!
To me, this seems to be something intuitive. Or am I misreading something here? I would think that if the earth’s axis tilt changed, weather patterns would change also. And therefore, over time, so would the climate.
The latitudinal shifting or changes in size, shape or intensity of the main high and low pressure cells (including the ITCZ) is actually the negative system response to changes in the proportion of solar energy that reaches the surface and/or gets into the oceans.
If that proportion changes for whatever reason then global temperature will change but the shifts in the atmospheric circulation minimise the thermal effect for the system as a whole.
The temperature of the system will always be controlled by atmospheric mass, gravity and the proportion of solar input that gets absorbed whilst passing through the system. Conduction from surface to the air above is the overwhelmimg process of absorption for Earth.
Radiative capability within an atmosphere only alters certain characteristics of the global air circulation pattern and not average surface temperature simply because the thermal effect of GHGs occurs off the surface rather than at the surface as per the new work of David Evans and as per my work here:
http://joannenova.com.au/2015/10/for-discussion-can-convection-neutralize-the-effect-of-greenhouse-gases/
Simply put, the effects of GHGs in distorting lapse rate slopes cause convective adjustments that neutralise the net thermal effect of those GHGs.
Really?
I seem to recollect the effect of the Earth’s tilt and orbital eccentricity on climate was taught at school in the 1950/60s…
I think this is a great site, of enormous value in educating on climate matters. Having said that, one thing that bugs me here quite often is the implicit acceptance of the practice of lumping of unmeasured/inferred “numbers” and measured observations.
Uncritical reproduction of a phrase like “data from the past 282,000 years” falls into this category. What’s being referred to here is “measurements from the last 30-300 years (in the case of supernovae dates and suchlike, maybe a little longer)” and “guesses, extrapolations, or other estimates for the previous 281,700+ years”.
I apologize if this point has already been made above or elsewhere. I do think it’s important to keep in mind.
Interesting article. As I read it, and addressing some other points, all it points out is that apparently the ITCZ doesn’t move north or south as was thought, it expands or contracts depending on where we are in the cycle. With regards to droughts in Central America and China and a connection to the cycle, it seemly means that at that point in the cycle, the ITCZ has shifted in a direction that resulted in drought at a particular latitude. I don’t see why that is inconsistent with a 41,000 year cycle. Theoretically at least, the ITCZ today is the same as it was 41,000 years ago. 4,000 years from now, it will have contracted or expanded and it’s effects on climate at particular latitudes will be different than it is today. However, I think leaving out the other Milankovich cycles is an error as the 23,000 year precession cycle should alter the changing tilt effects. It isn’t hard to create a chart that shows the combined affects of the three different cycles at a particular latitude. Depending on how they line up, you could get some really nasty winters at one pole or the other when you get a conjunction of an extreme aphelion, maximum tilt away from the sun, and a wobble that makes that tilt even more. Brrrr. And a blazing summer when the opposite occurs.
For a lot of the time, hot/cold effects will have some cancellation, but I’d like to see if the peak effects are reflected in the glacial record and temps in the northern and southern hemispheres. I’ve done some searching to see if anyone has tried to find a correlation but I’ve been unsuccessful.
“New research shows Earth’s tilt influences climate change” Not any more. With the conclusion of the Paris climate agreement, all climate change has suddenly ended for now and all time. Physics no longer matters. Milankovitch cycles nor anything else, including a super nova of the sun, can possibly affect our climate because of the Paris climate agreement. The agreement fixes all of our current climate and weather problems for now and for all time and we here in the USA do not have to pay anything for it because we are a very poor nation with a huge national debt, huge trade deficit, and huge unfunded liabilities.
Promise?
Keith Minto December 15, 2015 at 1:31 am
Thanks, Keith. I can’t say that I was impressed by the correlations shown in the paper. I’m taking a deeper look now … at least they archived their data.
w.
Difficulty. They’ve used a strange program called “redfit” to estimate the spectra of the unevenly sampled data. It’s a bizarre method. The method I use gives the spectra of unevenly sampled data directly.
I do NOT find the peaks that they find in the MD05-2925 G. ruber δ18O (‰, VPDB) data. I also do not find any adjustment for autocorrelation, nor any Bonferroni correction.
Onwards,
w.
And it is open access.
The paper intrigues me, the drill studies off New Guinea and in Australia, but linking Siberia / Australian weather is a stretch.There are too many other weather factors going on here to be clear about this study but good on them for the attempt. Look forward to your analysis.
So. How are we going to blame human flatulence for the variability of the tilt, not to mention changes in perigee and apogee and orbital parameters….that will, of course, result in billions of research grants to support the whole AGW religion searching for an impossible solution?
From the article above: Word and punctuation are unchanged, only paragraph structure is modified.
I could not find any reference to Fourier analysis nor even to any mathematical prism. The only reference to ‘spectral’ was an oblique reference to spectroscopic analysis.
Searching the actual research ‘Obliquity pacing of the western Pacific Intertropical Convergence Zone over the past 282,000 years’ for the above referenced author’s name ‘DeLong’ finds her down under affiliations.
The main authors are
‘Yi Liu’, High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University and
‘Li Lo’, Department of Earth Sciences, University of Cambridge
Kristine L. DeLong’s contributions are not specifically identified or quantified that I could locate. That mathematical prism type analysis is still unidentified.
Nor could I find out what a stalagtite is. The cave formation used are stalagmites. Normally in a typo, one can quickly see the error, but ‘t’ is not near ‘m’ on a keyboard. Confusion and/or comprehension are likely; Thinking stalactite while copying stalagmite and ending with with stalagtite is possible (confusion)…
Bringing up a next problem, DeLong’s reference to ‘paleontological’. Paleontological is valid when referring to studying dead critters in sediment cores, but not when studying stalagmites which would fall under geological studies.
More confusion, blame confusion on the press release authors, not poor ms. DeLong.
It’s nice that Willis is planning to learn new things while studying the archived data; but with the frequent mention of ‘models, simulated and simulation through the linked research, Willis may not enjoy much beyond the High-Precision Mass Spectrometry approach, I don’t hold much hopes for the data.
ATheoK December 15, 2015 at 7:30 pm
I always learn new things, and since I just learned about complete ensemble empirical mode decomposition (CEEMD) I thought I might as well apply it to their data. Not to their model of precipitation 250,000 years ago, but to the long-term g. ruber ∂18O records from the drill site MD05-2925.
?w=640
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Now, this is a fascinating decomposition. Note the large differences in the spacing of the observations, with recent observations being much more frequent.
Now, their claim is that there is a signal at ~41,000 years, congruent with the obliquity changes. However, I don’t see anything like that. Here are the spectra of the intrinsic modes 1-8;
As you can see, the majority of the signal strength is in the longer-period intrinsic modes, with little strength in the shorter-period modes. I see no significant 41,000 year cycles.
w.
+2
Very quick and very cool use of the CEEMD method Willis.
Those spectra periodograms showing some frequency signals in the 150K-500K years section of the core. Those signals appear to accelerate in frequency as age decreases.
I have to wonder about their sampling techniques, for it appears that as compaction and density increased, their samples, while defined as one age, represent a much longer interval as age increases.
The complete ensemble decomposition is very intriguing. What 41,000 period? What cycles?
Trying, just trying to find any excuse for a cycle, the C1 and C3 ensemble members show what appears to be a cardiac murmur of a very rough 20K year basis. It is not sinusoidal, especially in the original data where it appears the increase in g. ruber ∂18O causes the murmurs in C1 and the echoes in C3.
Yes, very cool Willis! Thank you.
It has always been my understanding that the obliquity cycle goes from 24.5 to 21.5 not 22.1 as depicted in the graphic . Has this been verified as an official change? Or are they using the 22.1 because it fits their narrative better? Using 21.5 means that there is one degree of change every 6,833 years. Using 22.1 takes that out to 10,250 years and I have never seen that number before.
This may well be an important scientific paper. But sadly, under the new world order belief system, carbon dioxide emissions from human activity is the key driver of climate change and nothing else matters.
In 1992, 350 years after Galileo’s death, the Roman Catholic Church finally repealed the ruling of the Inquisition against Galileo, and admitted the heliocentric theory of Copernicus was correct.
It remains to be seen whether it will take 350 years for the United Nations to acknowledges its IPCC mantra was false.