New findings from the Neotropics suggest contraction of the ITCZ

News Release 14-Feb-2020

Warmer climate leads to current trends of social unrest and mass migration

University of New Mexico

The University of New Mexico research team was led by Professor Yemane Asmerom (3rd from left) and included (l. to r.): Valorie Aquino, Keith Prufer and Victor Polyak. The team found contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America. Credit: The University of New Mexico

The University of New Mexico research team was led by Professor Yemane Asmerom (3rd from left) and included (l. to r.): Valorie Aquino, Keith Prufer and Victor Polyak. The team found contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America. Credit: The University of New Mexico

Research by an international team of scientists led by University of New Mexico Professor Yemane Asmerom suggests contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America, and aggravating current trends of social unrest and mass migration.

Positioned near the equator where the trade winds of the northern and southern hemisphere converge, the ITCZ is the world’s most important rainfall belt affecting the livelihood of billions of people around the globe. Globally, seasonal shifts in the location of the ITCZ across the equator dictate the initiation and duration of the tropical rainy season. The behavior of the ITCZ in response to the warming of the Earth is of vital scientific and societal interest.

Previous work based on limited data suggested a southward migration of the ITCZ in response to global cooling, such as during the Little Ice Age a few hundred years ago. In contrast, modeling and limited observational data seemed to suggest the ITCZ expands and contracts in response to cooling and warming. Which of these scenarios is correct has a huge implication for understanding rainfall variability and its economic and social impacts across the tropics. In order to resolve these seemingly contradictory alternatives the authors undertook this paleoclimate reconstruction study from the margin of the ITCZ and combined that with existing data from across the full annual north-south excursion of the ITCZ.

The study titled, “Intertropical Convergence Zone Variability in the Neotropics During the Common Era,” was published today in Science Advances. In addition to UNM, the research also includes scientists from the University of Durham (UK), Northumbria University (UK) and the University of California, Santa Barbara.

“Much of our understanding of ITCZ variability was based on records from South America, especially the Cariaco Basin (Venezuela), which was the gold standard,” explained Asmerom. “But these studies were only able to present half of the picture. As a result, they suggested southward movement of the mean position of the ITCZ during cool periods of Earth, such as during the Little Ice Age, and by implication it shifts northward during warm periods.

“This would imply regions in the northern margin of the ITCZ, such as Central America would get wetter with warming climate. This contradicted modeling results suggesting drying as a consequence of warming.”

With two testable hypotheses, Asmerom and his colleagues used 1,600 years of new bimonthly-scale speleothem rainfall reconstruction data from a cave site located at the northern margin of the ITCZ in Central America, coupled with published data from the full transect of the ITCZ excursion in Central America and South America. The combined data elucidate ITCZ variability throughout the Common Era including the warmer Medieval Climate Anomaly and the cooler Little Ice Age. The results of this study are consistent with models suggesting ITCZ expansion and weakening during global periods of cold climate and contraction and intensifying during periods of global warmth.

“Stable isotopic data obtained at Durham University, and trace element data and a precise uranium-series chronology, with an average 7 year uncertainty, obtained at the University of New Mexico, provided us with a nearly bi-monthly record of past climate variability between 400 CE to 2006. This level of resolution is unprecedented for continental climate proxies”, said Polyak.

“What we found was that in fact during the Medieval Climate Anomaly Southern Belize was very dry, similar to modern central Mexico. In contrast, during the Little Ice Age cool period, when it should have been dry by the standard old model, it was the wettest interval over the last 2000 years,” said Asmerom. “The pattern that emerges when all the data across the full transect of ITCZ excursion is supportive of the expansion-contraction model.” The implication of this that regions currently in the margins of the ITCZ are likely to experience aridity with increased warming, consistent with modeling data from Central America. These data have important implications for rainfall-dependent agriculture system on which millions of people depend for food security.

Co-author and UNM Professor of Anthropology Keith Prufer is an environmental archaeologist, who has been conducting research in Belize for 25 years. “In the last five years there have been mass migrations of people in Guatemala and Honduras – partially driven by political instability, but also driven by drought-related conditions and changes in seasonality. This is creating enormous problems for agricultural production and feeding a growing population. There is growing evidence that these changes are a direct consequence of climate change.”

“This work highlights the convergence of good science with policy relevancy. It also illustrates the strength of cross-disciplinary collaborative work, in this case international,” said Asmerom.

###

Additional co-authors include James Baldini, Lisa Baldini, Colin Macpherson and Harriet Ridley (University of Durham), Valorie Aquino (UNM), Sebastian Breitenbach (Northumbria University) and Douglas Kennett (The University of California, Santa Barbara).

From EurekAlert!

Advertisements

67 thoughts on “New findings from the Neotropics suggest contraction of the ITCZ

  1. Another “what if”, and then …and we can tell you what will happen. B.S. Meter at full tilt here.

    • Current annual rainfall in Belize is 60-160″ per year.

      They calculated that an extremely wet tropical rainforest environment would have less rainfall in a warming world, then applied that to the marginal agricultural area within the ITCZ to come up with a crisis for feeding humans.

      If rainfall declines 20% in the wettest portions of the ITCZ, but increases 10% in the driest portions and in the farmed portions, then humans would probably be much better off. (Assuming we even trust their model.)

  2. Same data determined that eating eggs is good for you. Also that drinking coffee is d bad.

    Migration and unrest are caused by bad policies and better opportunities elsewhere.

    • Fossil fuel combustion and global warming also cause:
      * Corona virus
      * Hemorrhoids
      * Toenail fungus
      * Planters warts
      * Explosive diarrhea
      * The heartbreak of psoriasis
      * Wilder weather
      * Human sacrifice
      * Dogs and cats living together
      * Mass hysteria…

        • Nah, not buying it

          Previous work based on limited data suggested a southward migration of the ITCZ in response to global cooling, such as during the Little Ice Age a few hundred years ago. In contrast, modeling and limited observational data seemed to suggest the ITCZ expands and contracts in response to cooling and warming.

          Now everyone knows that there was no Global Cooling related to any so called Little Ice Age. Michael Mann told us so.

        • Michael Mann told us so –

          Michael Mann Lawsuit: Climate Scientist’s Plan to “Ruin” National Review

          A few days before launching his lawsuit against what he called “this filthy organization,” Michael Mann wrote that there “is a possibility that I can ruin National Review.” Nearly a decade later, we are still fighting his attempt to do precisely that.

          https://www.nationalreview.com/2020/02/no-michael-mann-you-arent-going-to-ruin-this-filthy-organization/

    • ALLAN MACRAE February 16, 2020 at 4:11 pm

      Fossil fuel combustion and global warming also cause:

      * Corona virus
      * Hemorrhoids
      * Toenail fungus
      * Planters warts
      * Explosive diarrhea
      * The heartbreak of psoriasis
      * Wilder weather
      * Human sacrifice
      * Dogs and cats living together
      * Mass hysteria…

      ____________________________________

      OMG – That forbidden mh-word again.

      Members of Germany’s Greens party pose behind a banner against hate speech in 2019 | John MacDougal/AFP via Getty Images

      Berlin moves ahead with tougher hate speech legislation – POLITICO:

      https://www.politico.eu/pro/berlin-moves-ahead-with-tougher-hate-speech-legislation/

      Mass hysteria – http://www.medicalnewstoday.com

      In sociology and psychology, mass hysteria (also known as mass psychogenic illness, collective hysteria, group hysteria, or collective obsessional behavior) is a phenomenon that transmits collective illusions of threats, whether real or imaginary, through a population in society as a result of rumors and fear (memory …

      https://en.m.wikipedia.org › wiki

      List of mass hysteria cases – Wikipedia

      https://www.google.com/search?q=Mass+hysteria%E2%80%A6&client=

  3. The idea that climate change, in this age of technological achievement, when food production is continually going up everywhere around the globe, is driving mass migration is laughable.

    It’s policy, period. Why is “science” providing political cover to thugs and dictators? Castro didn’t need to blame the climate to totally wreck Cuba and send it scrambling to the edges of civilization. He did that all on his own.

    This is unbelievable.

  4. “In the last five years there have been mass migrations of people in Guatemala and Honduras – partially driven by political instability, but also driven by drought-related conditions and changes in seasonality.”
    “Partially driven by political instability…..” Partially? Really???

    Stable and citizen beneficial governments act to ameliorate the damage to public infrastructure and citizens real property caused by adverse weather events. You don’t see mass migrations from countries with stable and citizen beneficial governments.

    Conversely, Guatemala and Honduras are characterized by civil war, corruption, disease, and political persecutions. Pretending ‘Climate Change’ has anything to do with their problems is ludicrous.

    • Guatemala El Salvador and Honduras are far north of the real tropics. There have been no mass migrations from Costa Rica, Panama or Columbia, which are tropical Central America. Or even from bad old Nicaragua for that matter. I live in the mountains of Panama right on the continental divide. There is no drought, our coffee estates are producing record crops (thanks also to CO2 I suppose) and rainfall is normal. Panama has a stable and prosperous democracy. People are buying cars and big screens and settling in for the long run.

      One cave in Venezuela? Horse exhaust. And “published records” of temperatures? I have searched long and hard for these records, and they either don’t exist or are at best sketchy. And Panama was relatively advanced compared to the other countries sited.

      Clickbait prostitutes and money grubbers have invaded the temples of science. Who will drive them out?

  5. Since warming is essentially zero or even really cooling, their model might need more tuning. It is not the climate that is urging immigration northward, it is globalists stirring up people and touting a porous border, as if the peasants deserve to go to the U.S. Venezuela being the wonderful place that it is, there is also impetus for people to move north.

  6. In the last five years there have been mass migrations of people in Guatemala and Honduras – partially driven by political instability, but also driven by drought-related conditions and changes in seasonality.

    Here we have the intersection between Climate Change and Political Change.
    What are the metrics? Where are the error bars?
    This is science?

    • Perhaps this could be modelled. Then we could study the results of our own assumptions. If you would just send money I will happily tell you what you want to hear.

  7. In the earliest days of my interest in climate and “global warming” I read a ClimateAudit post headed, “Possible ITCZ Influence” — a topic I knew nothing about. It pops up now and then but not as a big important subject of interest among climate researchers. I’ve often wondered why.

    Possible ITCZ Influence
    https://climateaudit.org/2007/02/13/possible-itcz-influence/

    Narrowing of the ITCZ in a warming climate: Physical mechanisms
    https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL070396

    Understanding the width of the ITCZ
    https://climate-dynamics.org/tag/itcz-dynamics/
    The intertropical convergence zone (ITCZ) is narrow, but why? Was the ITCZ narrower or wider in past climates? How will the width of the ITCZ respond to global warming? These questions challenge our understanding of climate dynamics, and have implications for the impact of climate change in the tropics.

    And so on.

    • The ITCZ is always rather narrow. The reason? It is a convergence zone. Not easy to converge over a wide area.

      The climatologically important thing is how far north and south it moves during the year since it is this that defines how far north and south the tropical rains extend. And where the deserts start.

      During really warm intervals like the previous interglacial it reaches so far north that the tropical summer rain zone meets the mediterranean winter rain zone. That is when the Sahara goes green. It only happens briefly at the peak of some interglacials in this icehouse climate era.

  8. Everybody with any knowledge of paleoclimate knows that the ITCZ and monsoonal climates expands away fom the Equator during warm periods.

    When is the Sahara green?
    When are there lakes in the Rub-al-Khali?
    When do the dry lakes in Australia fill?

    When the climate is warm

    When does the Nile cease to flow?
    When do the Thar and Gobi deserts grow?
    When do the Amazon forests fragment and are partly replaced by savannas?
    When does the Kalahari desert expand north into Kongo?

    When the climate is cold

    • “When is the Sahara green?
      “When are there lakes in the Rub-al-Khali?
      “When do the dry lakes in Australia fill?

      “When the climate is warm”

      Spot on! One might even suspect ocean evaporation increases with temperature. Monotonically! … to LOL

      The most alarming thing about Climate? That so many “scientists” are able to get away with (and get PAID for) this INCESSANT level of production … the product being CLAPTRAP. Ugh.

  9. Do these idiot know anything, I live in Mesa, AZ the last ice age this area was covered in ponderosa pine, you know to have that happen we would need more rain. So I would assume yes it might rain more in Central America during a cold period. Oh by the way at the same time a good chunk of Nebraska, Kansas, Colorado and Wyoming were covered in sand dunes. The mass migration is not cause by climate change its the rulers down there making life impossible due to the political climate, not what you experience outside. Add in the problem is the same type of political system most of the eggs heads here in the US university want for us, the question if I have to move do to life is unlivable what more likely a bunch of socialist took over and made live unlivable or would it be climate change. If you say climate change you are and idiot.

    • I once visited Mesa many years ago. I remember some kind of parade for the Red Mesa Redskins football team. They were quite proud of its achievements. Hope they are still doing fine.

    • No, suggestions aren’t meaningful results. There are a lot of weasel words in the climate science of today. Of course, all they can do is suggest, since they don’t have any hard evidence.

      • The word SUGGEST is used seven times.

        I suggest these scientist go and do proper research (including Africa) and only publish when they have moved on beyond mere suggestion! 🙂

  10. What are these “Medieval Climate Anomaly” and “Little Ice Age” thingies of which they speak. Are they saying that Michael Mann is full of sh!t?

    • I’m surprised they still call it the Little Ice Age. They hate the Medieval Warm Period and they sure aren’t going to call it the Medieval Optimum. At least they admit that the Medieval Warm Period was warmer than the Little Ice Age.

    • The “Medieval Climate Anomaly” is an anomaly because it was warmer than before and after, and probably also warmer than today. But CO2 was not elevated. Warming without the influence of CO2 cannot be explained by the settled science, so let’s just call it an anomaly and forget about it. Climate science! Where conclusions come first! Where data gets adjusted to conform! (and if it’s too inconsistent with the conclusions, it gets disappeared)!

      There was no link to the actual paper (typical of Eureka Alert) but it’s open-access and can be seen and downloaded here:

      https://advances.sciencemag.org/content/advances/6/7/eaax3644.full.pdf

      I didn’t know what “Neotropics” are, so I looked it up in Wiki. Neotropics means “Central and South America” and it extends from Southern Florida (the line is somewhere between Tampa and Miami) to Tierra del Fuego. The Neotropics don’t extend to Africa or Asia. So “neotropics” has nothing to do with the tropics. One of the most misleading terms I’ve seen lately. If not ever.

      The study presents data from a speleothem in a cave in Belize. It seems to be very good data. The objection that one can make is not the data quality, but the conclusions that they draw from it seem to go beyond what is reasonable. The paper is quite short and worth reading for anyone interested in paleoclimatology (which should be all of us).

      The “suggestion” that the ICTZ may disappear with increased global warming seems to be a bit of a reach. A warmer world, but with no tropical thunderstorms? If the oceans get hotter, where is all the water vapour from increased evaporation going to go?

      • The ITCZ lies north of the Equator. Why do the UN IPCC climate models continue to show it both north and south of the Equator?

  11. Their study explains why people are fleeing the oppressive climate and oppressive politics of Texas and fleeing to cooler and better governed New York. Oh wait …

  12. Brazil keeps producing record crops of soybeans every year so that must mean that the area is getting colder.

  13. From the article: “Research by an international team of scientists led by University of New Mexico Professor Yemane Asmerom suggests contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America, and aggravating current trends of social unrest and mass migration.”

    “Including Central America”, huh. That’s funny. The next thing you know these scientists are going to try to blame the thousands of illegal aliens trying to enter the U.S. on CAGW. I have a feeling that’s what they are building up to. I’ll continue reading.

    Build that Wall! Build that Wall! 🙂

  14. It used to be called the “Medieval Optimum”.
    At least these pigs at the public trough are recognizing that there was a warm period then.
    But Michael Mann “disappeared” it because CAGW theories could not and cannot explain that warming.
    But with his follies, which continue, he is working on one of the greatest acts of professional infamy in history.

  15. Contraction of the ITCZ ? Really ? The monster of all monsters, friendly known here as “pot au noir” contracts, eventually calms down?

    The scariest of all scary weather events meet there. A cumulus is already a bad encounter, envision hundreds of them appearing here and there, up and down to play real scale whack a (frozen) mole with those daring to join the party without invitation.

    And now finally good news, no more need to carry extra spare pants. Is there something global warming can’t do?

  16. From the article: “The behavior of the ITCZ in response to the warming of the Earth is of vital scientific and societal interest.”

    Well, in that case, these scientists should go study what the ITCZ was doing during the hot 1930’s.

    Hansen said that 1934 was 0.5C hotter than 1998, which makes 1934 0.4C hotter than 2016. The year 1934 was at the so-called “IPCC tipping point” of 1.5C above the global average from 1850 to the present. The globe is about 0.8C cooler today than in 1934.

    Yet there was no tipping point in 1934, although the weather was severe all around the globe. But we recovered and are doing just fine today. So what was the ITCZ doing during the time of the warm 1930’s?

    Oh, that’s right, you scientists have been hypnotized by that fraudulent, Modern-era Hockey Stick surface temperature chart so you don’t know that the 1930’s were a very hot period, do you.

    That would make sense since the fraudulent Hockey Stick turned the 1930’s into an insignificant time period. You see, the Climategate Charlatans and their spawn couldn’t promote the CAGW Lie without erasing the warmth of the 1930’s. So they did.

    It might be worth checking out what the ITCZ was doing during that 1930’s timeframe, just the same, if you want to study a time that was 1.5C warmer than the global average from 1850 to the present, including warmer than all of the 21st century.

    Here’s the fraudulent, Modern-era “hotter and hotter” Hockey Stick chart. Note the position of 1934 and 1998 on the chart. Both of those years should be shown to be just as warm as 2016, the so-called “hottest year evah!”. You could draw a straight line connecting all three dates, 1934, 1998, and 2016, and that would represent the true temperature profile of the globe. Actually, we are in a slight downtrend in temperatures from the 1930’s.

    https://bobtisdale.files.wordpress.com/2018/12/Reference-Figure-1.png

    All regional Tmax charts from both hemispheres show that the 1930’s were just as warm as today, yet we are plagued with this bogus, fraudulent Hockey Stick chart that has fooled millions of people into believing it actually is getting hotter and hotter and hotter. But nothing could be further from the truth. The Tmax charts tell the tale.

    Here’s the UAH satellite global temperature chart. Look at 1998. You will see that it shows to be just one-tenth of a degree cooler than 2016, the “Hottest year evah!”, and both dates temperatures are within the margin of error so they could be tied for the “hottest year evah”, except we know from Hansen that 1934 was even warmer.

    Does the UAH chart downgrade 1998? No, it doesn’t. It looks nothing like the fraudulent Hockey Stick chart, does it.

    The UAH chart is the only one you can trust. All the rest have been manipulated for political reasons to make it appear as though the Earth is at the hottest point in human history.

    UAH satellite chart:

    http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_January_2020_v6.jpg

    I saw Australia’s Turnbull on the 60 Minutes show tonight. He’s a real piece of work. He wants to blame the skeptics for everything.

    • Tom,
      I caught 60 Minutes tonight. I noted that the ‘climate expert’ claimed that 2019 was the hottest and driest in history. Somehow, she overlooked the 1930s, which Jo Nova has been documenting recently.

      • “I caught 60 Minutes tonight. I noted that the ‘climate expert’ claimed that 2019 was the hottest and driest in history. Somehow, she overlooked the 1930s”

        It sounds like that climate expert needs access to this Tmax chart of Australia which shows there is no unprecedented warmth in Australia today.

        https://bobtisdale.files.wordpress.com/2018/12/Figure-12-2.png

        That Turnbull fellow said Australia should continue to cut it’s carbon dioxide even though China and India’s carbon dioxide output would completely nullify any Australian efforts to cut CO2. Turnbull seemed to think that setting a good example for others was a good reason to continue cuttng Australian CO2. Even though noone else is doing so. I guess that qualifies as Virtue Signaling.

        That was the first time I ever heard Turnbull speak and I only heard a few sentences come out of his mouth but that was enough to tell me that Australia is lucky to be rid of this guy. He’s completely out to lunch and has no business running a country.

  17. ““This would imply regions in the northern margin of the ITCZ, such as Central America would get wetter with warming climate. This contradicted modeling results suggesting drying as a consequence of warming.””

    Good thing it isn’t warming then… right? I mean other than rising out of the horror conditions of the LIA – which I note at least these people are acknowledging as an actual event.

    Although they also call the MWP the “Medieval Climate Anomaly” to try and marginalise it so we can’t look at it and decide maybe climate moves in cycles…

  18. ““What we found was that in fact during the Medieval Climate Anomaly Southern Belize was very dry, similar to modern central Mexico. In contrast, during the Little Ice Age cool period, when it should have been dry by the standard old model, it was the wettest interval over the last 2000 years,” said Asmerom.”

    So during the MWP (their Medieval Climate Anomaly) when populations flourished across the Northern Hemisphere (Greenland, SW US 4 Corners for example), was bad because Belize was dry. And then when the LIA arrived and Belize got wet and verdant, it was a great time?

    These people are insane.

  19. Say what???
    I thought settled science had already concluded that the Medieval Warm Period only impacted Europe.

      • Well, former president Barack Obama once said that Hawaii was in Asia. He also said that he had visited 57 states in the USA, so maybe one of them was the state of confusion.

  20. “Stable isotopic data obtained at Durham University, and trace element data and a precise uranium-series chronology, with an average 7 year uncertainty, obtained at the University of New Mexico, provided us with a nearly bi-monthly record of past climate variability between 400 CE to 2006.”

    This might be some very useful data. I wonder if anyone has graphed it.

  21. A geo would have just gone and looked at the evidence first, mapped it, got it dated, not used a climate model at all, and would still have derived the same or better results, from less dollars.

    “Look mum! My climate model works!”

  22. I lived in Kenya for 7 yrs during which time the United Nations Environment Programme (Nairobi) did an intensive study there (late ’90s) showing how removal of tree cover in tropical zones causes a multiplier effect of aridification, and thus changes in local and regional climactic conditions: reduced cloud formation so less moisture; rapid soil erosion; loss of fertility; loss of forest watercourses otherwise created continually by deep-rooted tropical species breaking into underground water sources; denuded land made vulnerable to storm and landslides and top soil loss. Add to this: multinational monoculture agriculture using water resources on an industrial scale (flower farming especially etc) AND impoverished smallholder farming methods AND the rural population using mainly wood for cooking and heating AND a multitude of small charcoal making businesses destroying the bush AND poor governance = an unholy downward spiral to mass poverty and climate degradation and migration. And all actually man-made. Much can be fixed too – where there’s a will. E.g. World Bank-China’s massive Loess Plateau regeneration scheme
    https://www.worldbank.org/en/news/feature/2007/03/15/restoring-chinas-loess-plateau

  23. “Much of our understanding of ITCZ variability was based on records from South America, especially the Cariaco Basin (Venezuela), which was the gold standard,”
    and then:………
    “This would imply regions in the northern margin of the ITCZ, such as Central America would get wetter with warming climate. This contradicted modeling results suggesting drying as a consequence of warming.”

    Let’s see know.. “based on records” and then ..”this contradicts modeling results..”
    what ARE we to believe? Unless in fact the tail really DOES wag the dog.
    Cheers
    Mike

    • That’s why this study is a set up based on a strawman. Hence my post linking to Leroux’s and Barbier’s work

  24. All I know is, when the last administration was telling people to come in for free, and their corrupt governments wanted them to go as well, and the idea that the USA would be handing out food, money and healthcare like it’s free, that wasn’t the REAl reason for the rush to migrate to the US, it was a hypothetical, not actually experienced minor change to the tropics that caused it.

    I hear there’s a forest nearby, but with all these trees, it’s really hard to find.

  25. This study is pure smokescreen.
    “Much of our understanding of ITCZ variability was based on records from South America, especially the Cariaco Basin (Venezuela), which was the gold standard,” explained Asmerom.
    That is really not true: Marcel Leroux’s work in Africa has done much to understand the structure of the ITCZ as well as its seasonal and climatological changes.
    http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf
    In typical climatology publications, there are very few reference to actual weather and how it is generated. Besides, the Asmerom paper fails to quote the important thesis by Barbier 2004 that provides these weather facts.
    https://hacenearezkifr.files.wordpress.com/2018/05/barbier-2004.pdf
    Contrary to what Asmerom claims, it is during cold periods and rapid mode of circulation that the Meteorological Equator zone contracts (see Fig 15 of the 1993 Leroux paper).
    Selective bibliography and not replacing their proxy observations in a global context make this new paper weak and opportunistic.

  26. ‘ITZ moves in response to warming (and cooling).’

    BRAVO! SO WHAT? What causes all this warming and cooling?

    I’ll wait.

  27. Much of sub-Saharan western Africa is a few degrees north of the equator, and receives heavy rainfall in (Northern Hemisphere) summer when the ITCZ moves north, and a dry season when it moves south (off the coast) in winter. The rainy season becomes drier as one moves north away from the coast toward the Sahara desert, but the southern edge of the Sahara desert has received increasing rainfall in recent years, which has allowed the range of grazing land to extend northward. This seems to contradict the trend observed in Central America by the writers of this article.

    • If you read the graduate textbook “Paleoclimatology” you will find that the ITCZ moved several hundred kilometers north during the Holocene climate optimum. This turned the Sahara, which is the size of the United States, from a desert to a well watered plain. It also turned the American midwest into a desert.

      This, we are all going to die in a warming world crap is just a fear mongering marketing campaign.

  28. “Much of our understanding of ITCZ variability was based on records from South America, especially the Cariaco Basin (Venezuela), which was the gold standard,” explained Asmerom. “But these studies were only able to present half of the picture. As a result, they suggested southward movement of the mean position of the ITCZ during cool periods of Earth, such as during the Little Ice Age, and by implication it shifts northward during warm periods.

    “This would imply regions in the northern margin of the ITCZ, such as Central America would get wetter with warming climate. This contradicted modeling results suggesting drying as a consequence of warming.”

    With two testable hypotheses, Asmerom and his colleagues used 1,600 years of new bimonthly-scale speleothem rainfall reconstruction data from a cave site located at the northern margin of the ITCZ in Central America, coupled with published data from the full transect of the ITCZ excursion in Central America and South America. The combined data elucidate ITCZ variability throughout the Common Era including the warmer Medieval Climate Anomaly and the cooler Little Ice Age.

    The results of this study are consistent with models

    suggesting ITCZ expansion and weakening during global periods of cold climate and contraction and intensifying during periods of global warmth.

    ____________________________________

    What is considered manic behavior?

    A manic episode is an emotional state characterized by a period of at least one week where an elevated, expansive, or unusually irritable mood exists. …

    People describe a manic mood as feeling very euphoric, “on top of the world,” and being able to do or accomplish anything. Oct 11, 2019

    https://psychcentral.com › disorders

    Manic Episode Symptoms – Psych Central

    https://www.google.com/search?q=manic+behavior+useless+repetition&oq=manic+behavior+useless+repetition+&aqs=chrome.

    ____________________________________

    Manic Episode Symptoms – Psych Central, euphoric testing useless Models against Real World experience.

Comments are closed.