Why there is so much disagreement about the Holocene Climatic Optimum

[Lagom]

The climate reconstruction for the Northern Hemisphere is so different from the rest of the world that estimates of global surface temperature can easily be manipulated by choosing and weighting different studies.

 

[super rat]

Anyone who has been paying attention knows its ALL bullshit. All designed to get the biggest bedwetters amongst up whipped up into a froth. Tell the lunatics to calm the fuck down or go do something useful like throw a can of tomato soup on some old shitty art but don't pay any attention to thier hysteria.

 

[Solera2012]

Tony Heller has been on these con-artists for years. You would think after Al Gore invented the internet, he could of at least told the truth on climate. Or was becoming a millionaire the incentive!

 

[autostaretx]

@Lagom, pray tell, what/where is the source of that graph?

thanks
--dick

 

[erik.wahlstrom]

Andy May “petrophysicist”. https://andymaypetrophysicist.com/

 

[autostaretx]

Just for the heck of it, i asked ChatGPT:
why is there a wide variation in the temperate anomalies for the different latitudes during the holocene climate optimum ?

and it answered:
The Holocene Climate Optimum (HCO) was a period of relatively warm temperatures that occurred between about 9,000 and 5,000 years ago. During this time, the Earth's temperature was on average about 0.5-1.0°C warmer than it is today, with some regions experiencing even greater warming.

One of the main reasons for the wide variation in temperature anomalies during the HCO is the uneven distribution of solar radiation across the Earth's surface. Solar radiation varies depending on latitude, with areas closer to the equator receiving more intense sunlight than areas closer to the poles. As a result, temperatures at different latitudes are affected differently by changes in solar radiation.

Another factor that contributes to the variation in temperature anomalies is the complex interactions between the Earth's atmosphere, oceans, and land surface. For example, ocean currents can transport heat from one region to another, and changes in atmospheric circulation patterns can affect the distribution of heat and moisture across the planet.

Additionally, factors such as topography, vegetation cover, and ice cover can also influence local temperatures. For example, regions with more vegetation tend to have cooler temperatures than regions with less vegetation, because plants release water vapor through a process called transpiration, which cools the surrounding air.

Overall, the variation in temperature anomalies during the HCO can be attributed to a combination of factors, including differences in solar radiation, atmospheric and oceanic circulation patterns, and local environmental conditions.
-----end quote----------

Not mentioned in the above is that the Earth was 1/3rd to 1/4 of the way around our precession circle/wobble ... the north star wasn't Polaris. If anything, it was probably Thuban (Alpha Draconis) (8000 years ago). That wobble would also have shifted how close we were to the sun (location of perihelion as mapped against "calendar day-of-year") . Currently we're closest to the sun on January 3rd or 4th (leading to warmer northern hemisphere winters).

--dick

 

[autostaretx]

Andy May “petrophysicist”. https://andymaypetrophysicist.com/

The figure's caption said "May 2018 Chap 4" and "here"
Can you supply where "here" is/was (i.e. the link)
I'm starting to plow through andymaypetrophysicist site, but the "here" may help me find the background faster.

thanks
--dick

 

[super rat]

The sun is where the heat comes from,.. don't make me say it,... dipshit.

 

[erik.wahlstrom]

I suspect OP got it from here. https://wattsupwiththat.com/2023/02/24/holocene-co2-and-the-earlier-ipcc-reports/
That blog post references chapter 4 of here. https://andymaypetrophysicist.com/climate-catastrophe-science-or-science-fiction/?amp=1

But I’m not going to pay the $9 on Amazon for the kindle version to find the underlying references, if any.

 

[autostaretx]

The climate reconstruction for the Northern Hemisphere is so different from the rest of the world that estimates of global surface temperature can easily be manipulated by choosing and weighting different studies.

Since the studies about the NH HCO number in the thousands from all over the planet (the Chinese are recently doing a lot of work in the area, as well as the Scandinavian countries) it's no longer "only a few studies" to (cherry-)pick and choose from to "bend the curve".
European and Chinese studies overlap at their respective borders, so that would tend to expose one side "cooking the books" compared to the other.

Picking a Chinese study at random (it was "above the fold" in Google Scholar), the abstract says " the Holocene optimum, as defined by peak East Asian summer monsoon precipitation, was asynchronous in central and eastern China, reaching a maximum at different times in different regions, e.g., ca. 10,000–8000 yr ago in northeastern China, 10,000–7000 yr ago in north-central and northern east-central China, ca. 7000–5000 yr ago in the middle and lower reaches of the Yangtze River, and ca. 3000 yr ago in southern China. In southwestern China the maximum appeared ca. 11,000 yr ago, but probably was related to the maximum landward extension of the Indian summer monsoon. The regional shift in the maximum precipitation belt from northwest to southeast over the past 10,000 yr is interpreted as a response to changing seasonality related to orbital forcing of the climate."

That study looked at Lake growth and shrinkage, the pollen found at various depths of drilled cores (type and populations of plants with known climate-tolerance characteristics), soil and dust types in the cores (and lake deposits), plus:
"About 11,000–10,000 cal yr BP, summer (July) solar radiation in the Northern Hemisphere reached a maximum (8% more than the present value; Prell and Kutzbach, 1987), thereby amplifying the seasonal contrast expressed in the summer monsoon index "
Part of their results is showing the path of the Indian Monsoon moving northward during that chunk of time.

Thus (echoing @super rat) they see the sun as a primary driver for the HCO:


Fig. 15. Solar radiation anomaly (departure from present) (ΔS) compared with the East Asian monsoon index (the difference of sea-level pressure between 160° and 110°E Longitude along 25–50°N Latitude) and the tropical Indian monsoon index (the difference of sea-level pressure between ocean and land within the region 45° to 120°E Longitude and 45°N to 15°S Latitude (ΔM(hPa); Prell and Kutzbach, 1987) at 3000-yr intervals since 15,000 astronomical yr BP. Positive values of the ΔM index indicate generally lower pressure over land compared to the ocean. The monsoon indices are calculated from the climate-model simulations for July using CCM0.
---------------
The "Prell and Kutbach" reference is:
W.L. Prell, J.E. Kutzbach; Monsoon variability over the past 150,000 years,
Journal of Geophysical Research, 92 (1987), pp. 8411-8425

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JD092iD07p08411

---------------------------

The black NH curve in Lagrom's chart doesn't have error bars or a surrounding gray area to show the "confidence" of the curve.
As the Chinese abstract exemplifies, variations where laterally as well longitudinally spaced.

--dick

 

[autostaretx]

... but (reading a bit further on) the Chinese went on to say:
Orbital forcing, however, is not the only control on the Chinese summer monsoon climate, for solar radiation in the Northern Hemisphere began to increase before 15,000 cal yr BP, whereas the precipitation in most parts of eastern China did not increase until 9000 cal yr BP, and in some places it even decreased. This discrepancy likely is related to glacial boundary conditions (i.e., the remnant ice sheets and the lowered concentration of carbon dioxide in the atmosphere during the last glaciation that delayed the development and advance of the East Asian summer monsoon; the associated low air temperature also decreased the water-vapor content of the atmosphere, both factors being unfavourable to an increase in East Asian monsoon precipitation).

So 8% more sun that we have now is an *input*, but not the whole story (gotta get rid of those glaciers up north first).

21,000 years ago, CO2 was down around 200 ppmv (that's off to the left in the WattsUp chart).

--dick (dropping off line for the night)

 

[Lagom]

it's no longer "only a few studies" to (cherry-)pick and choose from to "bend the curve".

Sorry, Dick, but I'm going to call Bullshit on you again. The phrases you put in quotes in your reply to me are not my words, and you know as well as I that calculating a global surface temperature indeed involves selecting and weighting the results of multiple studies. Obviously this creates an opportunity for disagreement (hence the title for the post).

I am a little suspicious of May's northern hemisphere curve. Other reconstructions I have seen had distinct signals for the Medieval Warm Period and the Roman Warm Period, and his doesn't. There are historical data for these events that don't rely on proxy measures, and I think most reasonable people accept that something was going on at those times in the NH, climate-wise.

I'm just pointing out the difficulty in using proxy data to prove or disprove the magnitude of the Holocene Climatic Optimum. We're making a lot of expensive decisions based on modeling, and any model that doesn't predict the HCO should have us asking why not.

 

[autostaretx]

. The phrases you put in quotes in your reply to me are not my words,

They weren't intended to be .. i was quoting them to have them viewed as typical idioms.
(quoting idioms is a writing style i frequently use)

and you know as well as I that calculating a global surface temperature indeed involves selecting and weighting the results of multiple studies. Obviously this creates an opportunity for disagreement (hence the title for the post).

Yup... and continual delving into the HCO makes a narrow selection of data sources less and less accepted.
(the provided graph wasn't "global", it was regional)

I am a little suspicious of May's northern hemisphere curve. Other reconstructions I have seen had distinct signals for the Medieval Warm Period and the Roman Warm Period, and his doesn't. There are historical data for these events that don't rely on proxy measures, and I think most reasonable people accept that something was going on at those times in the NH, climate-wise.

The lack of an obvious MWP may just be seeing it averaged out around the planet.
I don't "do" (<-- idiom) the Holocene curve very often or very much .. i usually just see the MWP in pieces in passing when reading abstracts that mention how it played out in the American southwest. Like the Chinese study, the "hot spots" (and droughts) were not simultaneous.
Something i hadn't run across before was that blatant presentation of an 8% swing in insolation to the NH.
I'll have to go back to typical Milankovitch curves/papers to see if shows up there.
As the Chinese curve (sourced from another reference) hints, the solar output was still dropping as we got to "now". One reason i'm in the "warmist" camp is that the current trend in insolation has (after a small hump) been fairly steadily dropping since the late 1970s ,,, yet the global temperature (either by direct measurement, or by its effects on proxies like animal migrations and vegetation changes) has been still rising.
Which kind'a mitigates a staunch "it's the sun" position.
Yes, the sun can overwhelm CO2's (and other GHGs) forcing, but at the moment it's not.

I'm just pointing out the difficulty in using proxy data to prove or disprove the magnitude of the Holocene Climatic Optimum. We're making a lot of expensive decisions based on modeling, and any model that doesn't predict the HCO should have us asking why not.

One thing that the May curve shows (cited simply because i only have to scroll up to see it) is that its bouncy line did not change more than half a degree from its long-term fully-smoothed curve. Eyeballing it does not show a full degree upswing in (say) 150 years (unlike what we're living through (see final sentence)).
Downswings are shorter and steeper (hello, asteroid? (such as the Greenland impactor?) ... and volcanos giving the planet "shade")

May's full curve is a multi-thousand-year example of "the climate is always changing" ... to which i'll add "slowly".
... and that sudden spike at the "now" end of it is what i'm concerned with.

--dick

 

[autostaretx]

The climate reconstruction for the Northern Hemisphere is so different from the rest of the world that estimates of global surface temperature can easily be manipulated by choosing and weighting different studies.

You may actually be quite surprised that i agree that the "putative HCO" curves have "issues".

I just use different terminology ... instead of a purely emotive "bullshit", i tend to use the (far more damning in the proper circles) phrase "the data is inconsistent".

--dick

 

[Solera2012]

Not surprised at all. Always stay with topics where there is no answer.

Is there a God?

What came first, the chicken or the egg?

When facts emerge, subsequent to the original argument, and begin to cloud a previous position, refrain from further assertion, and move to the next topic.

Pfizer used the "data was inconsistent ". But they chose to hide it, and injure many.

When the whistleblower reported her known facts during drug trials, to the corrupt FDA, within a day Pfizer knew, and she was fired. Now, her suit for damages is in a federal court in TX, where Pfizer is arguing for dismissal.

Ah, the regulators are regulating.

 

[ECU]

Randal Carlson.

 

[autostaretx]

What came first, the chicken or the egg?

That's actually easy ... the egg.

Whatever evolutionary progenitor laid that egg was not a chicken ... it took the specific genetic mix (and mutations) of that specific egg's single cell to create/become "a chicken".
(ref: biochemist Nick Lane's excellent book: Oxygen, the Molecule that made the World )

--dick

 

[autostaretx]

I am a little suspicious of May's northern hemisphere curve. Other reconstructions I have seen had distinct signals for the Medieval Warm Period and the Roman Warm Period, and his doesn't. There are historical data for these events that don't rely on proxy measures, and I think most reasonable people accept that something was going on at those times in the NH, climate-wise.

I'm just pointing out the difficulty in using proxy data to prove or disprove the magnitude of the Holocene Climatic Optimum. We're making a lot of expensive decisions based on modeling, and any model that doesn't predict the HCO should have us asking why not.

So i went and read a bit of the paper (Markott et al) where May got his latitude curves.
Marrkott et al spend their paper describing the methods and statistics they used, and they compare their curve to two "famous" ones: Mann's tree-ring-to-data -based "hockey stick", and another tree ring study.

Here's a sliced-and-diced-and-annotated (by me, such as adding the MWP pointers) selection from their first figure (the A,C,E etc described in the quote text below):



They write:
----
We took the 5° × 5° area-weighted mean of the 73 records to develop a global temperature stack for the Holocene (referred to as the Standard5×5 reconstruction) (Fig. 1, A and B). To compare our Standard5×5 reconstruction with modern climatology, we aligned the stack's mean for the interval 510 to 1450 yr B.P. (where yr B.P. is years before 1950 CE) with the same interval's mean of the global Climate Research Unit error-in-variables (CRU-EIV) composite temperature record (2), which is, in turn, referenced to the 1961–1990 CE instrumental mean (Fig. 1A). We then assessed the sensitivity of the temperature reconstruction to several averaging schemes, including an arithmetic mean of the data sets, a 30° × 30° area-weighted mean, a 10° latitudinal weighted mean, and a calculation of 1000 jackknifed stacks that randomly exclude 50% of the records in each realization (Fig. 1, C and D, and fig. S4). Although some differences exist at the centennial scale among the various methods (Fig. 1, C and D), they are small (<0.2°C) for most of the reconstructions, well within the uncertainties of our Standard5x5 reconstruction, and do not affect the long-term trend in the reconstruction.
In addition to the previously mentioned averaging schemes, we also implemented the RegEM algorithm (11) to statistically infill data gaps in records not spanning the entire Holocene, which is particularly important over the past several centuries (Fig. 1G). Without filling data gaps, our Standard5×5 reconstruction (Fig. 1A) exhibits 0.6°C greater warming over the past ~60 yr B.P. (1890 to 1950 CE) than our equivalent infilled 5° × 5° area-weighted mean stack (Fig. 1, C and D). However, considering the temporal resolution of our data set and the small number of records that cover this interval (Fig. 1G), this difference is probably not robust. Before this interval, the gap-filled and unfilled methods of calculating the stacks are nearly identical (Fig. 1D).
-----
and
---------
Our global temperature reconstruction for the past 1500 years is indistinguishable within uncertainty from the Mann et al. (2) reconstruction; both reconstructions document a cooling trend from a warm interval (~1500 to 1000 yr B.P.) to a cold interval (~500 to 100 yr B.P.), which is approximately equivalent to the Little Ice Age (Fig. 1A). This similarity confirms that published temperature reconstructions of the past two millennia capture long-term variability, despite their short time span (3, 12, 13). Our median estimate of this long-term cooling trend is somewhat smaller than in Mann et al. (2) though, which may reflect our bias toward marine and lower-latitude records.
-----------

So Markott's "more global" (since they included marine sampling) approach diluted Mann's land-only tree-ring spikes and bumps.
Markott also gridded the planet to 5 degree "squares"(not uncommon in climate modeling) and use long averages. The "formal" definition for the MWP is only 300 years (roughly 950 to 1250) ... which is only a "pixel or two" in the longer time-span that Markott was profiling.
Mann only cared about a 1500-year look-back, Markott was going longer (their 11,000 year curves were the B,D,F, etc set).

May (etc) didn't include the error bars (which is only a "one sigma" band), but it's the error range that lets Markott say (as he does) that his curve is "indistinguishable within uncertainty" to Mann's.

I'm not saying either (Mann's or Markott's) is "more correct", but they do describe how they got to where they got, and their papers include access to their background data ... so anyone "serious about the subject" can make use of it.
People doing serious research read the papers ... and then they chase down the references cited by those papers ... and then they chase down those references references AND they get copies of the data along the way (in my old job i'd prepare the data tapes and disks for such requests, and deal with ingesting to our system the tapes/disks from other sites (pre-internet)).

Us, as the "general public" on the outside looking in rarely go to the lengths that the people in the field of study do. But they do (in any scientific field) so that they won't make absurd (in their colleagues' view) errors from lack of chasing down the fine details.
That's how the system works, and it's how simple errors, systemic errors or downright falsifications get rooted out.

--dick

 

[Solera2012]

That's actually easy ... the egg.

Whatever evolutionary progenitor laid that egg was not a chicken ... it took the specific genetic mix (and mutations) of that specific egg's single cell to create/become "a chicken".
(ref: biochemist Nick Lane's excellent book: Oxygen, the Molecule that made the World )

--dick

Did Anthony Fauci lie on the origins of the Wuhan virus?

Did the US Taxpayers fund gain of function research, at the lab in Wuhan China?

Are you up to date on all your boosters, that are EUA status, even to this day?

 

[flman]

Some here will trust anything that is totally bogus. How many red flags until you stop being useful idiots to the boy that cries wolf? Did the government not lie to you enough yet, that you have to still be their lackey's? Not sure when they will actually wake up?