How Pressure Systems Control Climate Part 3

HOW THE SUN AND INTERTROPICAL CONVERGENCE ZONE (ITCZ) CONTROLLED CLIMATE AND CIVILIZATION COLLAPSES

Jim Steele

To ensure we properly adapt to future devastating weather events, we must correctly understand natural climate change. Natural weather disasters, much worse than those in recent times, have happened throughout history and will continue to happen regardless of any changes in human CO2 emissions.

The sun’s orbital cycles (the Milankovitch cycles) shift the ITCZ and Hadley circulation. Driven by the sun’s Milankovitch cycles, a steady 6000-year migration of the ITCZ towards it last glacial maximum southern extent ensued, coinciding with a cooling trend known as the neo-glaciation. That ITCZ migration and its linked high-pressure systems also changed the locations of the earth’s deserts and droughts and civilization collapses.

For a transcript visit:

https://perhapsallnatural.blogspot.com/2022/01/how-sun-and-intertropical-convergence.html

Jim Steele is Director emeritus of San Francisco State University’s Sierra Nevada Field Campus, authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism, and proud member of the CO2 Coalition.

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January 9, 2022 11:16 pm

Jim,

Very interesting discussion of the links of climate to history.

Thanks.

Reply to  Philip Mulholland.
January 10, 2022 12:58 am

All good stuff and consistent with the work of myself and Philip Mulholland which proposes changes in atmospheric circulation as the climate control knob rather than radiative gases.
The effect of those shifts in the climate zones is to adjust the rate at which energy radiates to space so as to maintain the hydrostatic equilibrium of the atmosphere.
To achieve that the surface temperature must always remain at a level consistent with the weight of the atmosphere, the strength of the gravitational field and incoming radiation from the sun.
Nothing can be allowed to disrupt that equilibrium.
The changes required to adjust for changes in the amount of radiative material within an atmosphere are minuscule compared to natural variability especially for an ocean world where the thermal inertia of the oceans and the speed of the water cycle help to make the adjustment process more efficient.

commieBob
January 10, 2022 1:33 am

Two things:

Thing 1: CO2 induced warming is different than solar-variability induced warming. Visible wavelengths (most of solar energy) penetrate the ocean deeply. Long Wave InfraRed (LWIR) produced by greenhouse gas back radiation does not penetrate the ocean and will mostly produce evaporation. In other words, if the oceans are warming, it isn’t due to CO2.

Thing 2: The correlation between Sahel droughts and sunspot minima is pretty convincing.

Ben Vorlich
Reply to  commieBob
January 10, 2022 5:34 am

Do you have a link for Thing 2?

I like having things like 2 to throw into a climate change discussion

commieBob
Reply to  Ben Vorlich
January 10, 2022 8:17 am

Thing 2 is a comment on the evidence presented by Jim starting at 13:14 in the above video.

MarkW
Reply to  commieBob
January 10, 2022 8:16 am

If the atmosphere warms, then the oceans will warm. It has nothing to do with CO2.
It has to do with the how quickly the warmth being added by the sun, is able to escape the oceans.

Reply to  MarkW
January 11, 2022 8:05 am

Correction, if the oceans warm the atmosphere will warm, hence the issue with CO2 being the cause.

dh-mtl
Reply to  commieBob
January 10, 2022 8:17 am

re: Thing 1: In other words, if the oceans are warming, it isn’t due to CO2.

Yes! And ocean temperatures drive global atmospheric temperatures. Not only are oceans 75% of the surface, but they greatly influence all coastal areas.

One most also take into account:

  1. For the solar energy that penetrates deep into the ocean, there is a significant time lag, between the time the energy enters the ocean and the time it shows up as surface temperature, – of the order of decades.
  2. There is a natural ocean temperature cycle, with a periodicity of ~ 70 years (for example AMO and Willis Eschenbach (Adding it Up – 2021-04-09) shows that all of the ocean cycles are connected). There are no external forces at this particular periodicity, so it is internal to the ocean circulation patterns.

The above two points are usually not accounted for in theories of climate change.

fretslider
January 10, 2022 1:56 am

This was most informative. – earlier on the radio Roger Harrabin gave us the latest doom watch – thank god for WUWT

Ben Vorlich
Reply to  fretslider
January 10, 2022 5:37 am

Justin Rowlatt on the 7 warmest years since records began on BBC lunchtime News

auto
Reply to  Ben Vorlich
January 10, 2022 1:28 pm

Ben,
You know, of course, that the Beeb’s records ‘begin; in 2013 . . .

Auto

Alexander Vissers
January 10, 2022 2:24 am

This contributes to the intuïtive conviction that relatively smal changes in solar irradiation can have a significant impact on climate. As for the current era, if solar irradiation is increased by 1.5 W/m2 in the past decades (CERES) ocean heat content increase by 0.6 W/m2 should not be surprising nor should changes in weather patterns.

Ron Long
January 10, 2022 2:39 am

Fascinating review by Jim, especially as regards climate induced cultural collapse. It looks like the Green Energy funding would be better spent in building infrastructure to allow civilizations to adapt to changing climate during natural climate cycles, than pursuing costly and inefficient energy alternatives. Nuclear? Great for dependable power and desalinization of sea water. Will the population of the Los Angeles Metroplex collapse when there is no more water to rob from their neighbors?

Beta Blocker
Reply to  Ron Long
January 10, 2022 5:03 am

In the late 1970’s and early 1980’s, the oil companies which were then exploring the economics of developing the Colorado oil shales understood that considerable volumes of process water would be needed to convert the extracted kerogen into a proto-petroleum material suitable for further refining.

The kerogen to proto-petroleum conversion process was best performed at the mine sites in Colorado, but with one major issue to be resolved. Where does all that process water come from? (Certainly not from the Colorado River.)

Two major solutions were proposed. One solution was to divert a portion of the Columbia River’s flow and pipe it from the US Northwest to Colorado. The other was to use a fleet of nuclear reactors located along the California coast to desalinate sea water and to pipe it to Colorado.

The benefit of the latter proposal was that water for all of California’s civil and agricultural needs could also be produced from these nuclear powered desalination plants, if enough of them could be constructed. And the oil companies would be paying a portion of the construction and operating costs for these desalination plants.

The oil shale mines in Colorado would have been the largest surface excavations ever attempted on earth. Looking at these proposals from my perch inside the nuclear industry, it was my opinion at the time that if the citizens of Colorado ever came to realize just how much environmental damage these oil shale mines were going to inflict, anyone working on these mining projects would have been tarred and feathered and run out of the state on a rail.

Last edited 4 months ago by Beta Blocker
Ron Long
Reply to  Beta Blocker
January 10, 2022 5:55 am

Beta Blocker, I worked for Gulf in Denver in 1975/76, and then for CONOCO 1976 to 1984. I was on a Technical Advisory Committee for both, and the issue of these oil shales came up. Oil shale has the kerogen locked in place, it is a different geology than fracking shales, which give up the oil when fractured with open spaces. One other potential source of water for the oil shale process was the basin waters regularly encountered during drilling for oil. These basin waters were salty, sulfurous, noxious, and stinky, and it was quickly realized they were an environmental disaster waiting to happen.

bonbon
Reply to  Ron Long
January 10, 2022 9:35 am

My colleagues, with clients all over the oil world, knew shale was a looser. So what changed all that was the sudden availability of FED liquidity after the 2007 crash. These companies took on huge debt, interest free and fracking suddenly took off.
The liquidity here is not salty water but $trillions pumped out by the FED at astronomical volumes.
A financial disaster is waiting to happen…

Ron Long
January 10, 2022 4:07 am

Sorry, a little off topic, but I just watched a filler series of photos and short video clips on CNN. One shows children in about 6 to 10 inches of snow building a snow man and playing. The caption reads (paraphrase) “Children enjoying playing in the snow in Kabul, Afghanistan.” The reality is that Afghanistan is undergoing an economic collapse and brutal treatment under the Biden-enabled Taliban. Children are being sold as sex slaves and are starving, all during an unusually severe and brutal winter. Here, playing out before us, is the terrible consequence of cultural dysfunction and very cold cycles.

Tom Abbott
Reply to  Ron Long
January 10, 2022 5:21 am

It’s a disaster unfolding before our eyes. It didn’t have to happen.

bonbon
Reply to  Ron Long
January 10, 2022 5:50 am

Biden basically stole $9 billion from Afghanistan, which must immediately be released, or watch genocide enfold. 40 years of war and now looted.
London stole Venezuela’s gold.
This is Grand Theft on a massive scale.

MarkW
Reply to  bonbon
January 10, 2022 8:19 am

Got any evidence for either of those claims, or should the voices in your head be sufficient for all of us?

bonbon
Reply to  MarkW
January 10, 2022 9:27 am

Even the Poodle can find that :

https://www.bloomberg.com/news/articles/2021-08-17/u-s-freezes-nearly-9-5-billion-afghanistan-central-bank-assets

https://www.ft.com/content/6b401c73-88c6-4e7e-a064-877e357aa0df

When they asked Dillinger why he robbed banks, he answered that was where the money is. Here we have the banks robbing countries, because that is where the loot is.

pochas94
January 10, 2022 5:14 am

I read this as saying that 13,000 years from now when the north pole points to the sun when the earth is at perigee in its orbit, the ITCZ will move northward and the desert zones along with it.

MarkW
Reply to  pochas94
January 10, 2022 8:20 am

As long as we have a moon, the north pole will never face the sun.

Tom Abbott
January 10, 2022 5:28 am

From the transcript: “Climate scientists from NOAA also tested for effects from greenhouse gases but reported that the IPCC’s climate models failed to simulate those contrasting ocean temperatures or the ITCZ ‘s southern shift suggesting the droughts were “likely of natural origin”

The models failed to simulate. . .

I like Jim’s explanation for how the Earth’s weather works. NOAA is missing the boat, being fixated on CO2, as they are.

Peta of Newark
January 10, 2022 6:28 am

Sorry Jim but this is yet another of your intricate ventures into a mountain of minutiae.

The efc tsof Milankovitcch et ets are far too small and would chewed up and swallowed down bu a healthy and properly/normally working Earth System

All those lovely advanced and settled civilisations, chock full of ‘butter wouldn’t melt’ humans, exactly as we are now, destroyed themselves.
They did it by the very fact that they were ‘settled’
So they ploughed and tilled and grazed and grazed and fertilised all the land around until they had removed, Naature helped with winf and rain, removed all the vital ad essential trace elements and nutrients from their lands where they got their food.

On top of which, all the bare soil left behind ploughs and hoes and rakes and whatever tools they had, removed the soil organic matter that previously held it all together and very importantly, retained moisture within the soils.

When all those things were gone (bare soil being the Real Killer) they found themselves ‘settled in the middle of a desert and all those prevuios nicely settled sugar babes simply gathered up their stuff and wandered off in whichever direction took their fancy.

They created the desert and the Climate changed to reflect that. No soil organics means no soil water mean very high temps when the sun shines and no possibility of clouds forming to shade it and those rapidly convectiong columns of hot air changed the circlation paterns for hundreds if not thousands of miles around.

Sorry peeps and I repeat myself (for the nth time where n is now a large positive integer) – that process of desert creation is exactly what we as a world-wide human collective are now doing – it is exactly CO2 levels and temps are rising.
But for us, the CO2 is skyrocketing because we have 250HP tractors to do the ploughing, we have chainsaws to destroy the forest even before grotesgue and monstrous tree-eating machines arrive on the scene.
And simply because there are soooooo many of us asking for that ploughing and tillage to be done. And 6 new Londons every year are surely going have and epic heating effect – have can they not – why are they so studiously ignored exactly as in dissertations as we have here?
6 new Londons annually is NOT= Natural Variation
Now at the state that if it all stooped tomorrow, inside 3 months 80% of world population would have died.

wrap up warm people

edit to add:
Basicaly Jim, you have got Cause & Effect reversed.
You are effectively studying the goings on in an empty stable – the horse is long gone.
What you should be doing is chasing after the horse and catching it so as to enquire why it bolted in the first place

Last edited 4 months ago by Peta of Newark
Jim Steele
Reply to  Peta of Newark
January 10, 2022 7:13 am

Basically Peta, You. are cherry picking and seem to have big blinkers on regards anything you disagree with .

Although I too believe that landscape deterioration has played a part in some regional desertification, you cannot blame an even larger Sahara desert during the last glacial maximum on human disturbances. Not the greening of the Sahara during the Holocene maximum which is the opposite of what suggest

MarkW
Reply to  Jim Steele
January 10, 2022 8:22 am

Peta has claimed that deserts are caused by too many fires destroying the soil, and have nothing to do with how much rainfalls.

Duane
Reply to  MarkW
January 10, 2022 9:11 am

Deserts are created by lack of rainfall, period. Soils cannot be “destroyed”.

The wettest places on earth – tropical rain forests – have relatively little soil cover, rather the abundance of rain creates a huge biomass that over time contributes to “forest duff”, which is essentially mostly organic material with little geologica material. Which is why when tropical rain forests are cleared and burned, they remain productive only a few years before the “soil” is exhausted of nutrients. Much of the “soil” in the Florida Everglades is actually “muck”, which is mostly organic material that, when exposed to air and sunlight oxidizes away, such that over time eventually most of that muck will be gone leaving little agricultural productivity in the “Everglades Agricultural Area” that was reclaimed by draining the Everglades in the 20th century. It’s not really “soil”, just as “forest duff” is not really soil. Soil will continue to exist as long as it does not erode away.

Duane
Reply to  Peta of Newark
January 10, 2022 9:05 am

Except, uhh … deserts are retreating world wide. Blows our theories all to hell and back.

Deserts come and go all the time. Five thousand years ago the Sahara was not a desert, but was a moderately watered savannah. No cities then, no SUVs, no Londons. It happened totally naturally with zero human influence .. and someday, the weather patterns will continue to evolve and turn the Sahara into a savannah yet again.

Here in the US, we’ve seen such changes occur throughout human history, such as in the desert southwest which supported a large civilization of prehistoric peoples until the 13th century, when over just a few years the southwest turned into a much drier desert, agriculture failed, and those peoples migrated into the Rio Grande river valley where they could continue to practice their irrigated agriculture because the flows in the Rio Grande continued due to annual snowpack in the southern Colorado Rockies, whereas the four corners area emptied out.

bonbon
Reply to  Peta of Newark
January 10, 2022 9:46 am

What, pray tell, is a ¨healthy and properly/normally working Earth System¨?
Maybe the Pope’s Gaia?

pochas94
Reply to  Peta of Newark
January 10, 2022 10:22 am

As Dr Steele explained, deserts form under the descending dry air from the Hadley cells. But like all Greenies working tirelessly to invert reality, you pretend (or actually) do not know this.

Gary Pearse
Reply to  Peta of Newark
January 10, 2022 6:53 pm

Peta, it won’t be news to you that pop today is closing on 8B, in 1960 it was ~3B, in 1760s it was ~0.8B, in 100AD it was 0.2-0.3B, in 1000BC it was some 50million, in 5000BC it was 5-20 million.

Surely the ‘damage’ done 5000 years ago by such a small population was inconsequential. Populations living for 10,000yrs in
The Americas hardly scratched the surface in terms of denuding the land. The low level of tech in farming and the availability of livestock and even wild grasslands animals (think 10 million buffalo on the Great Plains) kept the land fertile, as did flooding rivers, etc.

I’ve been trying to make the point re our ability to destroy the planet, that the energy level we can generate is vanishingly puny even if willfully applied, compared to the planet’s weather might, ocean currents’ might, solar irradiation, lightning, river flows and sediment transport. An estimate that global warming is equivalent to 4 Hiroshima bombs a second (since proven to be a 200-300% overestimate in failed warming rates from models) of which, even if we grant to climateers are caused by CO2, humans supplied only 4% of this – the rest is natural carbon cycle. Meanwhile our benevolent sun delivers the equivalent of 2700 Hiroshima bombs a second to the top of the atmosphere!

Coach Springer
January 10, 2022 8:00 am

To ensure we properly adapt to future devastating weather events” Not high on my list of musts. We seem to be thriviing with what we have. But … meteors.

pochas94
Reply to  Coach Springer
January 10, 2022 10:13 am

True, but if we can spot them in time, we can deal with them too.

RickWill
January 10, 2022 1:35 pm

In the Southern Hemisphere, the summer is from December to March inclusive.

An image that is showing predominantly South America, indicating summer September and March winter is not particularly precise.

RickWill
January 10, 2022 1:38 pm

The precession cycle in combination with eccentricity dominate the seasonal variation in solar input. Obliquity is important but its variation is negligible.

Jim Steele
Reply to  RickWill
January 10, 2022 3:20 pm

Obliquity is important because the further north the direct rays, the further the ITCZ’s position which draws warm cross-equatorial ocean currents further northward. The warming of the Arctic and subsequent cooling correlates with Obliquity. Read Huybers & Wunsch 2004 “Obliquity pacing of the late Pleistocene glacial terminations”

RickWill
Reply to  Jim Steele
January 10, 2022 5:30 pm

That Huybers paper is attempting to show that recovery from glaciation is linked to obliquity. It is not suggesting obliquity is the cause of glaciation. Others have determined that recovery from glaciation is related to the loss of vegetation and high dust levels that increases snow absorption.

Glaciation begins when the eccentricity is reducing and perihelion is later than the austral summer solstice. Recovery from glaciation requires increasing eccentricity and begins after perihelion is later in the year than the boreal summer solstice. Earth is currently in a glaciation phase.

Obliquity CHANGE is a bit player compared with precession in combination with eccentricity and the nominal obliquity:
https://futureofenergyinitiative.org/Pubs/Ellis.pdf

Obliquity describes the angle of the Earth’s axial inclination, which varies from 22.1 to 24.5 over an approximate 41 kyr cycle. The obliquity cycle can vary the insolation received in high northern latitudes by up to 25 W/m2, or about a quarter of the variation normally produced by the precessionary cycle. 

The linked paper also makes a case for loss of vegetation and dust as the recovery from glaciation rather than obliquity.

Jim Steele
Reply to  RickWill
January 10, 2022 7:08 pm

As I stated. in the video, the combination of obliquity and precession, but Rick says “bit player”???

From Huybers & Wunsch

“The null hypothesis that glacial terminations are independent of obliquity is rejected at the 5% significance level. In contrast, for eccentricity and precession, the corresponding null-hypotheses are not rejected. The simplest inference, consistent with the observations, is that ice-sheets terminate every second (80ky) or third (120ky) obliquity cycle—at times of high obliquity—and similar to the original Milankovitch assumption”

One can infer if high obliquity provides enough heat to terminate a glacial period, then low obliquity does not provide enough heat to stop initiation of glaciation.

Obliquity is only half way through its cooling phase, headed towards 22 degrees tilt. Precession has roughly finished its cooling phase and is now headed back towards its warmest phase. If precession is the driver then we would expect 26,000 year glacial periods. But we dont.

First there were ~40,000 year cycles then as the earth continued to cool, multiples of obliquity with glaciations terminating “every second (80ky) or third (120ky) obliquity cycle”, but those cycles have been misleadingly averaged into 100,000 year cycles to incriminate eccentricity. Bad averaging, just like average global temperatures.

And Rick you completely side-stepped the issue of obliquity’s effect on increased warm ocean transport into and out of the Arctic, instead pivoting to speculation about effects from vegetation and dust.

RickWill
Reply to  Jim Steele
January 10, 2022 10:52 pm

Precession has roughly finished its cooling phase and is now headed back towards its warmest phase.

There are two hemispheres and one is dominated by water. The precession cycle is now past its peak over the Southern Hemisphere and its extensive oceans. The water cycle is slowing down and more heat is being left in the oceans as the difference in insolation over land and water reduces; slowing deep ocean upwelling.

In the current era, ocean insolation is 398W/sq.m in January and land has its maximum of 337W/sq.m in May. As the precession cycle moves perihelion closer to the boreal summer solstice, the difference in insolation between oceans and land will reduce slightly. That reduces advection of moist air from oceans to land, most notably in December and January.

However the winters of the Northern Hemisphere are in a cooling phase and that will lead to more snow deposit and eventual accumulation. Glaciation begins with snow fall. Aphelion is now getting closer to the boreal winter solstice.

The maximum rainfall over land occurs in December and January when the difference between insolation over land and water is at its maximum 398w/sq.m and land 258W/sq.m or 140W/sq.m. When perihelion aligns with the boreal summer solstice the January difference will be 370W/sq.m and 241W/sq.m. or 129W/sq.m. The important fact here is that the January insolation over land will be 18W/sq.m less than now. And the colder land will be all in the Northern Hemisphere. Slightly reduced transfer of water to land but an increasing proportion will fall as snow. The current glaciation cycle started in 1585, the last time perihelion occurred before the austral summer solstice in 1585. Winter cooling is responsible for snow fall leading to glaciation.

RickWill
Reply to  Jim Steele
January 10, 2022 11:07 pm

instead pivoting to speculation about effects from vegetation and dust.

What I know for certain is that obliquity CHANGES are a bit player in the insolation. There is proxy evidence that shows dust increases dramatically during the depth of glaciation. It is far more plausible that dust changing ice/snow albedo is more significant than tiny insolation changes from obliquity changing:
comment image

https://www.sciencedirect.com/science/article/pii/S1674987116300305

Last edited 4 months ago by RickWill
Jim Steele
Reply to  RickWill
January 11, 2022 1:03 am

Rick, again you ignored my argument and only quoted half of what I said. “you completely side-stepped the issue of obliquity’s effect on increased warm ocean transport into and out of the Arctic, instead pivoting to speculation….”

RickWill
Reply to  Jim Steele
January 11, 2022 4:25 am

 obliquity’s effect on increased warm ocean transport into and out of the Arctic,

No I didn’t. I said the CHANGE in obliquity is negligible.

Here is the data:
In the present era North Pole gets an average insolation of 529W/sq.m in June. In 10,000 years the insolation will increase to 539W/sq.m. That is despite a reduction in obliquity from 23.08 to 22.25 and eccentricity from 0.0167 to 0.0114.

Precession dominates changes in insolation across the entire globe and more than offsets any changes in obliquity. The change would be greater if it was not partially offset by obliquity and eccentricity changes occurring as well.

The big change in the next 10,000 years will be the December insolation at the South Pole. Now 564W/sq.m. It will reduce to 517W/sq.m in 10kyr.

Ulric Lyons
January 10, 2022 2:01 pm

Jim, you have the most important part completely backwards. The AMO is always warmer during centennial solar minima, making the Sahel wetter. Stronger solar wind states in the 1970-1980’s drove a colder AMO (via the NAO/AO), causing Sahel drought, as in the early 1900’s. Weaker solar wind states since 1995 have driven a warmer AMO, causing a generally wetter Sahel.

The 1830’s were not during the Dalton Minimum.

Jim Steele
Reply to  Ulric Lyons
January 10, 2022 3:39 pm

Ulric you have an annoying habit of irrelevantly quibbling then arrogantly stating others got it all wrong as if you are the only authority

The dates I used are approximates because different authors commonly suggest different dates and definitions.

Regards the Dalton Minimum I often read it lasted from 1790-1830

In relation to the Sahel droughts many authors point to drying beginning in 1790 with 12-15 year drought from the 1820s and 1830s. So I will firmly repeat that the droughts at that time are closely associated with the Dalton Minimum.

Your boastful claim that I have it “backwards” when I suggest the cooling in the north Atlantic moved the ITCZ southwards, needs more evidence and clarification.

Are you arguing that Hoerling et al’s map of sea surface temperature trends from 1950-1999 is not showing cooling in the north Atlantic?

Ulric Lyons
Reply to  Jim Steele
January 10, 2022 8:45 pm

You do have it backwards, the AMO is always warmer during centennial solar minima, causing a wetter Sahel.

The Dalton Minimum was all done by 1820. Most of 1822-1835 is clearly back to a positive NAO regime, giving higher temperatures in Central England, and a colder AMO causing the Sahel drought.
https://www.metoffice.gov.uk/hadobs/hadcet/cetml1659on.dat

Your ad hominem does not win any scientific argument, and it is all self projections.

Ulric Lyons
January 10, 2022 2:22 pm

The 1610’s to the mid 1660’s had lots of remarkably warm and hot weather for Northwest Europe. That period is the very worst proxy for Little Ice Age conditions with increased El Nino conditions and a warmer AMO.

https://wattsupwiththat.files.wordpress.com/2011/09/weather1.pdf

The Maunder Minimum begins to impact English temperatures from the mid 1660’s, and then is notably cooler for most of 1672 to 1705.

https://www.metoffice.gov.uk/hadobs/hadcet/cetml1659on.dat

Jim Steele
Reply to  Ulric Lyons
January 10, 2022 3:48 pm

Again your arguments are quite irrelevant. The video is stating that the Maunder Minimum brought the ITCZ southward. That shift brought droughts to the Sahel. So you reply what??? That Maunder Minimum brought warm weather to northwest Europe???

To be more relevant to the issues at hand, why dont you present where the pressure systems were located over northwest Europe and how they shifted

Ulric Lyons
Reply to  Jim Steele
January 10, 2022 9:11 pm

Not so, my argument is critical. During the actual cold decades of the Maunder Minimum for Northern Europe, the AMO was warmer and the Sahel would have been wetter.

JS
“So you reply what??? That Maunder Minimum brought warm weather to northwest Europe???”

So you believe those weather chronicles of all that hot European weather before the mid 1660’s are false?

Jim Steele
Reply to  Ulric Lyons
January 11, 2022 12:57 am

 
 
Ulric, Let me expand on why I find you sooo annoying when trying to have a scientific discussion.
 
This video discusses the southward migrations of the ITCZ and subtropical
high-pressure systems and the effects on climates from the Mediterranean to the Sahel. Southward migrations of ITCZ brings winter drought to the Sahel. But as the linked high-pressure systems move south they allow the westerlies to bring winter rains to the Mediterranean region, while the. Sahara remains arid
 
But you want to make arguments using England’s weather, as if it should
inform me on.  What’s happening in the Sahel. That shows you really do not understand how the different pressure systems affect different latitudes, but that does not stop you from persisting in your irrelevant criticisms
 
Now some date the Maunder minimum to 1645 to 1715. Because the ITCZ seems sensitive to low sunspot numbers, as well as other dynamics that affect latitudinal temperatures, I am only concerned about the approximate time of low sunspots, and self righteous quibbling over exact dates is senseless.  A period of low solar energy output still seems to affect the ITCZ whether it is labeled a “minimum” or not.
 
You also seem to deny all the data sets that report Sahel drought during low sunspots
 
“Senegambia suffered droughts in each decade from the 1710s to the
1750s”
 
“Lake Chad experienced rapid falls in lake levels around
1680-1690,… attesting to desiccation in the area of northern Nigeria.”
 
“major droughts, persisting from 12-15 years, evidently occurred in the
1680s, the mid-1700s, the 1820s and 1830s
 
But you argue, “During the actual cold decades of the Maunder Minimum for Northern Europe, the AMO was warmer and the Sahel would have been wetter
 
Apparently, you latch on to northern Europe’s climate to deny the
reported Sahel droughts claiming “Sahel would have been wetter”. Then you weirdly ask me if I believe northern Europe temperature data is false,  when it is totally irrelevant.
 
I presented the graphic by Hoerling et al of a cooling north Atlantic and
warming south Atlantic that I referred to as an expression of the AMO. Again, I
am not concerned with a. precise AMO index cause there are a few indexes trying to detrend certain causes like CO2 warming. Nonetheless the hemispheric difference was obvious, and however you want to call it, would move the ITCZ southward and increase Sahel drought. So I asked you if you thought those SST were accurate, you did not reply, but you continue to deflect. Annoying!

sahel and AMO.jpg
Ulric Lyons
Reply to  Jim Steele
January 11, 2022 12:04 pm

JS:
“But you want to make arguments using England’s weather, as if it should inform me on. What’s happening in the Sahel. That shows you really do not understand how the different pressure systems affect different latitudes, but that does not stop you from persisting in your irrelevant criticisms”

You should stop associating lower solar activity with Sahel drought as the reverse is true. Positive North Atlantic Oscillation regimes drive a colder AMO causing Sahel drought. England weather is greatly dependent on the NAO so it’s a great proxy. That’s how Hurrell developed an NAO index back to 1659.
I understand but you don’t even want to, due to your confirmation bias of which decades were lower solar or not.

JS:
“Now some date the Maunder minimum to 1645 to 1715. Because the ITCZ seems sensitive to low sunspot numbers, as well as other dynamics that affect latitudinal temperatures, I am only concerned about the approximate time of low sunspots, and self righteous quibbling over exact dates is senseless.”

No it is critical which decades you refer to, and you have chosen drought episodes which occurred before the negative NAO regime of the Maunder Minimum, and after the negative NAO regime of the Dalton Minimum. Which has made you get the whole plot backwards and be self righteous about it.

“You also seem to deny all the data sets that report Sahel drought during low sunspots”

Senegambia and Lake Chad are on the southern margins of the Sahel, that’s not the best proxies.

“I presented the graphic by Hoerling et al of a cooling north Atlantic and warming south Atlantic that I referred to as an expression of the AMO.”

Which is the reverse of what occurs during the lowest solar periods.

“So I asked you if you thought those SST were accurate, you did not reply, but you continue to deflect.”

The trend from 1950-1999 is not much use, the AMO has since warmed during this Centennial Minimum, driving a warmer AMO, causing a generally wetter Sahel.

Jim Steele
Reply to  Ulric Lyons
January 11, 2022 1:17 pm

Ulric, You should stop with your BS. You just keep making things up. You have yet to provide any published evidence that a positive NAO causes Sahel Drought.You simply try to win an argument by obsessively repeating your BS ad nauseum.

The Sahel had 3 droughts between 2002 and 2012 when the NAO was negative, the complete opposite of what you have been spamming!!!

North Atlantic Oscillation NAO 2015.png
Ulric Lyons
Reply to  Jim Steele
January 11, 2022 7:43 pm

Positive NAO conditions drive a colder AMO, and which is associated with Sahel drought, as in the 1970-1980’s.
No BS there.

The AMO has been generally in a wetter phase since 1995 associated with the warmer AMO since then.
No BS there either.

Of course we can find some wetter years during the 1970-1980’s, and some drier years since 1995, but the exceptions are not the general rule.

Ulric Lyons
Reply to  Ulric Lyons
January 12, 2022 8:29 am

Correction, the Sahel has been in a wetter phase since 1995….

Ulric Lyons
Reply to  Jim Steele
January 13, 2022 10:13 am

Before reading this paper I predicted that 1969 and 1979 were wetter Sahel years within the dry period from 1965. On the basis that weaker solar wind states drove warmer AMO anomalies around those two sunspot cycle maximums.

Following the drought period of the ‘Red Sahel’ in the 1970s and 1980s and the
‘Greening of the Sahel’ in the 1990s and early 2000, the conception of a ‘Blue Sahel’
can only be seen as a euphemism for the devastating floods that have battered the
region since the 1990s. These floods have essentially occurred on an annual basis,
albeit in varying magnitude.”

https://www.zef.de/fileadmin/user_upload/40a1_FloodsinSahel.pdf

Jim Steele
Reply to  Ulric Lyons
January 13, 2022 8:14 pm

LOL. First you argue irrelevantly using England’s temperatures far to the. north of the Sahel, now you give me a paper on floods in Ghana south of the Sahel. Sahel’s rainfall is driven by the ITCZ period. when the ITCZ fails to reach the Sahel there’s winter drought and longer droughts. The ITCZ reaches typically Ghana and brings heavy rains. The weather station used in the paper you rely on are all below 8 N. The Sahel rainfall index measures rainfall between 10 & 20N. The “proper.” latitudes to define the. Sahel are

“Sahel” more properly applies to a smaller region (Figure 2) between the latitudes of roughly 14° N and 18° N. It includes much of the countries of Mauritania, Senegal, Mali, Niger, Chad, the Sudan, and the northern fringes of Burkina Faso and Nigeria.”

https://www.hindawi.com/journals/isrn/2013/453521/

Ulric Lyons
Reply to  Jim Steele
January 14, 2022 8:06 am

CET is not irrelevant through the LIA, it’s a relevant NAO proxy, and that paper discusses the wider Sahel region, as I had quoted.

John
January 10, 2022 10:04 pm

This is fantastic information and well worth a read

shame the AGW crowd are illiterate deaf and dumb

Tom Abbott
Reply to  John
January 11, 2022 2:56 am

Many in the AGW crowd are willfully deaf and dumb.

Martin Mason
January 11, 2022 9:25 am

A very good thoughtful analysis Jim. It is obvious now that the CO2 only climate control knob concept is a pile of pony. Look forward very much to part 4.

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