Changes In Vegetation Shaped Global Temperatures Over Last 10,000 Years

Peer-Reviewed Publication

WASHINGTON UNIVERSITY IN ST. LOUIS

Follow the pollen. Records from past plant life tell the real story of global temperatures, according to research from a climate scientist at Washington University in St. Louis.

Warmer temperatures brought plants — and then came even warmer temperatures, according to new model simulations published April 15 in Science Advances.

Alexander Thompson, a postdoctoral research associate in earth and planetary sciences in Arts & Sciences, updated simulations from an important climate model to reflect the role of changing vegetation as a key driver of global temperatures over the last 10,000 years.

Thompson had long been troubled by a problem with models of Earth’s atmospheric temperatures since the last ice age. Too many of these simulations showed temperatures warming consistently over time.

But climate proxy records tell a different story. Many of those sources indicate a marked peak in global temperatures that occurred between 6,000 and 9,000 years ago.

Thompson had a hunch that the models could be overlooking the role of changes in vegetation in favor of impacts from atmospheric carbon dioxide concentrations or ice cover.

“Pollen records suggest a large expansion of vegetation during that time,” Thompson said.

“But previous models only show a limited amount of vegetation growth,” he said. “So, even though some of these other simulations have included dynamic vegetation, it wasn’t nearly enough of a vegetation shift to account for what the pollen records suggest.”

In reality, the changes to vegetative cover were significant.

Early in the Holocene, the current geological epoch, the Sahara Desert in Africa grew greener than today — it was more of a grassland. Other Northern Hemisphere vegetation including the coniferous and deciduous forests in the mid-latitudes and the Arctic also thrived.

Thompson took evidence from pollen records and designed a set of experiments with a climate model known as the Community Earth System Model (CESM), one of the best-regarded models in a wide-ranging class of such models. He ran simulations to account for a range of changes in vegetation that had not been previously considered.

“Expanded vegetation during the Holocene warmed the globe by as much as 1.5 degrees Fahrenheit,” Thompson said. “Our new simulations align closely with paleoclimate proxies. So this is exciting that we can point to Northern Hemisphere vegetation as one potential factor that allows us to resolve the controversial Holocene temperature conundrum.”

Understanding the scale and timing of temperature change throughout the Holocene is important because it is a period of recent history, geologically speaking. The rise of human agriculture and civilization occurred during this time, so many scientists and historians from different disciplines are interested in understanding how early and mid-Holocene climate differed from the present day.

Thompson conducted this research work as a graduate student at the University of Michigan. He is continuing his research in the laboratory of climate scientist Bronwen Konecky at Washington University.

“Overall, our study emphasizes that accounting for vegetation change is critical,” Thompson said. “Projections for future climate change are more likely to produce more trustworthy predictions if they include changes in vegetation.”


JOURNAL

Science Advances

DOI

10.1126/sciadv.abj6535 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Northern Hemisphere vegetation change drives a Holocene thermal maximum

ARTICLE PUBLICATION DATE

15-Apr-2022

From EurekAlert!

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Craig from Oz
April 18, 2022 10:16 pm

Clearly trees are the root cause of Global Warming(tm) and we must glue ourselves to the gates of plant nurseries until awareness is raised.

Or something.

That is how Activism works, right?

Old Man Winter
Reply to  Craig from Oz
April 19, 2022 12:49 am

You mean it’s not that evil magical molecule CO2 but something that eats it up? Oh, the humanity! 😮

BTW, here’s a ™ you can cut, paste & save for your tm

Last edited 1 month ago by Old Man Winter
Duane
Reply to  Craig from Oz
April 19, 2022 8:46 am

No – it is how actual science works. My god you people here are stuck in your own little anti-science bubbles. There is every reason in the world to dispute warmunist dogma … but being anti-science isn’t one of them.

Dave Fair
Reply to  Duane
April 19, 2022 9:09 am

Duane, unexplained by the CliSciFi model “experiments” is the cooling beginning about 6,000 years ago. Unaddressed is the fact that the causal agency apparently falls apart.

It is the use of unvalidated models to “prove” anything that is in dispute. The models are speculative, based upon the primacy of CO2, assume large feedbacks that have not been observed and tuned to the late 20th Century warming period. Each iteration of the CMIP models is progressively worse at showing present climate metrics and in hindcasting.

Drake
Reply to  Duane
April 19, 2022 9:49 am

“Warmer temperatures brought plants — and then came even warmer temperatures, according to new model simulations published April 15”

CLIMATE CHANGE Model simulations ARE NOT SCIENCE, they are not DATA, they are just computer games configured to get the pre determined results desired..

MY GOD, YOU PEOPLE who think the computer models are science are the anti-science loons.

b.nice
Reply to  Duane
April 19, 2022 12:44 pm

Sorry, but no science was done in this study.

It just computer games.

PCman999
Reply to  Craig from Oz
April 19, 2022 2:45 pm

That’s what bothers me too, how could increased vegetation lead to warming – leaves have a higher albedo than rock and dirt.

Look at the dramatic greening of the past 50 years, and temp increases have leveled off in the last 20.

Bernie
April 18, 2022 10:18 pm

It all looked OK until: “Projections for future climate change are more likely to produce more trustworthy predictions if they include changes in vegetation.” Too bad about that.

Joao Martins
Reply to  Bernie
April 19, 2022 1:49 am

…”Projections for the future” producing “predictions”…???

Seems like using cristal ball and table-turning…

Duane
Reply to  Bernie
April 19, 2022 8:31 am

What the author said is correct. Better models will be those that incorporate the feedback effects of vegetation into their projections. For the same reason that climate models will perform better when properly taking account of the myriad of other parameters that affect climate, but that are conveniently ignored now in the warmunist models that seek to blame all changes in climate on atmospheric CO2.

Nicholas McGinley
April 18, 2022 10:51 pm

Keyword: Model.

’nuff said.
Not science.

Old Man Winter
Reply to  Nicholas McGinley
April 19, 2022 12:36 am

“Thompson had long been troubled by a problem with models of Earth’s atmospheric temperatures since the last ice age. Too many of these simulations showed temperatures warming consistently over time.

But climate proxy records tell a different story. Many of those sources indicate a marked peak in global temperatures that occurred between 6,000 and 9,000 years ago.
Thompson had a hunch that the models could be overlooking the role of changes in vegetation in favor of impacts from atmospheric carbon dioxide concentrations or ice cover.
“Pollen records suggest a large expansion of vegetation during that time,” Thompson said.
“But previous models only show a limited amount of vegetation growth,” he said. “So, even though some of these other simulations have included dynamic vegetation, it wasn’t nearly enough of a vegetation shift to account for what the pollen records suggest.”
In reality, the changes to vegetative cover were significant. …

Thompson took evidence from pollen records and designed a set of experiments with a climate model …. He ran simulations to account for a range of changes in vegetation that had not been previously considered.

“Expanded vegetation during the Holocene warmed the globe by as much as 1.5 degrees Fahrenheit,” Thompson said. “Our new simulations align closely with paleoclimate proxies. So this is exciting that we can point to Northern Hemisphere vegetation as one potential factor that allows us to resolve the controversial Holocene temperature conundrum.””

It may be a case where he broke the model The Team™ uses for climate research. Instead of just
looking at models for conclusions, he actually looked at data & realized the models were off. He
then made corrections that reflected real world data. This is what real scientists do. Unfortunately,
The Team™ may cancel him before it becomes habit-forming. It could become a contagion!!!

Last edited 1 month ago by Old Man Winter
Nicholas McGinley
Reply to  Old Man Winter
April 19, 2022 2:18 am

What he did amounts to tuning the models.
Parameterization.
This is one of the main reasons the modeled results are crap.
It sounds to me like he just added one more parameter to the parameterization.
For one thing, I am sure he is using the warmistas wrong data set of past temps.
They cannot admit that there were several periods, some of which were hundreds and even thousands of years long, when was far warmer during the past 10,000 years that it is now, and indeed far warmer than the amount of warming they claim is tantamount to “the end of life as we know it.”

This is the Holy Grail for the warmistas.
If it was warmer than now in past millennia of the Holocene, it wrecks their entire narrative, deader than dead. It is the same as if they just admitted they have been full of crap the entire time.

Last edited 1 month ago by Nicholas McGinley
Duane
Reply to  Nicholas McGinley
April 19, 2022 8:41 am

No – all models are in need of understanding the underlying processes they are designed to predict the performance thereof. The better the understanding, the better the model. The problem with most climate models is not modeling, the problem is that they’re bad models. But life is chock full of very successful models.

You could not post comments online at WUWT without the models that designed the internet, the electronics and computers that control the internet, the device that you are banging the keys of right now … the electrical power generators and distribution systems that power the net and your device .. the roads you drive on .. the medicines that keep you alive and health … the communications systems that you rely upon to get information about the world … every single bit of that is all designed based upon models that actually work extremely well.

Reply to  Duane
April 19, 2022 9:11 am

No again – trying to make a connection between inductive climate simulations and building bridges that don’t fall down is not going to work. Non sequitur.

Dave Fair
Reply to  Duane
April 19, 2022 9:17 am

Duane, the problem is that we are being politically compelled to fundamentally alter our society, economy and energy systems based on demonstrably unfit models. Playing games at their margins only reinforces rent-seeking bad habits.

meab
Reply to  Duane
April 19, 2022 10:32 am

Models that designed the internet? Models didn’t design the internet, DuhWayne. Everyone knows that Al Gore, the genius polymath, designed the internet.

Seriously, DuhWayne, models did not design the internet. Models were used to simulate ideas and, using the results of these simulations, improved concepts were formulated. By people.

Models that actually design things without human intervention are a fairly recent development.

There’s also one thing you don’t seem to be considering. While, in principle, it may be possible to understand the processes that underlie the climate (in principle, the state-of-the-art is far from it), climate physics are non-linear and chaotic. It’s not calculable, the tiniest errors will magnify as the simulation progresses, leading the trajectory of the prediction off from reality.

That’s why weather predictions are generally good for 3 to 5 days falling to a random chance of being correct after a week to two weeks (unless you’re predicting the weather for a place like the Atacama desert where the weather almost never changes.) That’s why multiple simulations are run on each climate model with slightly different starting conditions and assumptions and the results vary quite widely.
The poor performance of climate models is owing to both the intractability of the problem as well as poor knowledge/parameterization of the processes.

Doonman
Reply to  Duane
April 19, 2022 7:13 pm

The internet works by employing finite automata machines, not by employing coupled non-linear chaotic systems.

The IPCC says:

“The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible.”

So your premise is falsified. Find a better argument.

Nicholas McGinley
Reply to  Old Man Winter
April 19, 2022 2:21 am

Also, in general, more vegetative cover on the Earth does the same thing as more humidity: It warms, but it also cools.
Not as cold when it is cold, not as hot when it is hot. In other words, plants and trees moderate temperatures.
It is not a simple matter of warming.

Last edited 1 month ago by Nicholas McGinley
Clyde Spencer
Reply to  Nicholas McGinley
April 19, 2022 8:27 am

While I’m sympathetic to the idea of looking for alternative climate influences other than the simplistic — “We don’t know what else could be causing warming, so it must be CO2!” — approach, I’m concerned about the simplistic approach of using visible-light albedo.

First off, reflectance spectra of vegetation varies considerably, with the only commonality being having high reflectance in green light and even higher in near-infrared, and strong absorption in red and blue light. There is also a small specular component that approaches the spectrum of the sun for glancing angles, and is usually missed by relying on albedo rather than total reflectance. Reflectance also varies strongly by season. Furthermore, it appears that these researchers didn’t consider the impact of warming oceans on photosynthetic life in the oceans.

Duane
Reply to  Nicholas McGinley
April 19, 2022 8:43 am

Read the post that you are stupidly attacking. The author never said that vegetation causes warming, but that there is a correlation between vegetation cover and climate warming, based upon actual observed data, not the models. His point is that the models used generally for climate predictions aren’t doing a good job of reproducing results that are already established, and that one of the reasons is failure to consider the effects and feedbacks of vegetation.

Nicholas McGinley
Reply to  Duane
April 19, 2022 10:45 am

One of us has a serious reading comprehension problem.
Or maybe a not having any idea of what you are talking about problem.

Duane Sez: “Read the post that you are stupidly attacking. The author never said that vegetation causes warming…”

Author sez:
Warmer temperatures brought plants — and then came even warmer temperatures…”

““Expanded vegetation during the Holocene warmed the globe by as much as 1.5 degrees Fahrenheit,” Thompson said.”

Do you ever get tired of making an absolute jackass of yourself?

AndyHce
Reply to  Old Man Winter
April 20, 2022 10:14 pm

Or maybe warmer temperatures greatly expanded vegetation.

Duane
Reply to  Nicholas McGinley
April 19, 2022 8:35 am

Models are science. Every single effing thing in the worlds of science and engineering is designed and built based upon models. I get it that the WUWTers here like to denigrate all models as a sort of knee jerk exercise, but that is nothing but know-nothingism and Luddism, or celebrating ignorance and lack of understanding as a virtue.

A model is simply a means of understanding how the universe works. Anything that you calculate is a model. Math itself is a model for anything and everything, because anything and anything requires mathematics to understand and predict how any thing will act or react. Language is a model of human thought.

Models, of course are not all created equal. Some models are very good – like the models used to design airplanes, nuclear reactors, gas fired power plants, roads, buildings, bridges, dams and flood control systems, rocket ships, communications systems, electrical systems, electronics, automobiles and other vehicles, etc. etc. etc. Every single thing in life is designed based on models.

Last edited 1 month ago by Duane
Dave Fair
Reply to  Duane
April 19, 2022 9:28 am

Duane, please identify any of your WUWTers that “like to denigrate all models.”

Citizen Smith
Reply to  Duane
April 19, 2022 11:43 am

There goes Duane again with the big generalizations but missing the obvious point.
Models do not produce data.

Nicholas McGinley
Reply to  Duane
April 19, 2022 11:44 am

OMG, are you ever gonna give your ceaseless whinging and babbling a rest?

Your incoherent strawman arguments are only tiresome, nothing else.

Nicholas McGinley
Reply to  Duane
April 19, 2022 12:31 pm

The way warmista modelers use the models is not scientific, it is the opposite.
The scientific method is a process.
These guys do not follow the scientific method whatsoever.
Their models and more importantly how they use them are in fact an excellent example of what the scientific method replaced.

The way they tune and parameterize them is unphysical, and the way they double down on their claimed certainty in the validity of their results, even as those results diverge ever further from reality, is a corruption of the scientific method, as is their utterly cynical and by now verging on criminal alterations in the historical data sets.

It is only by publicizing faked versions of collected data, and erasing over a centuries worth of work by countless real researchers and scientists, that they can get away with the endless stream of lies that they use to perpetuate this travesty.

If they were being even slightly scientific, they would have long ago abandoned their long since falsified hypothesis of CAGW.
Literally every detail of the claims they make, are very close to the exact opposite of what is true, known, and verifiable.

So, no, these models, and the results which they claim have been experimentally verified, are categorically not science.
Francis Bacon developed the scientific method to put an end to people starting out with a desired result and ignoring any information which is contrary to the preordained conclusion.

“Bacon’s method is an example of the application of inductive reasoning. However, Bacon’s method of induction is much more complex than the essential inductive process of making generalisations from observations. Bacon’s method begins with description of the requirements for making the careful, systematic observations necessary to produce quality facts. He then proceeds to use induction, the ability to generalise from a set of facts to one or more axioms. However, he stresses the necessity of not generalising beyond what the facts truly demonstrate. The next step may be to gather additional data, or the researcher may use existing data and the new axioms to establish additional axioms. Specific types of facts can be particularly useful, such as negative instances, exceptional instances and data from experiments. The whole process is repeated in a stepwise fashion to build an increasingly complex base of knowledge, but one which is always supported by observed facts, or more generally speaking, empirical data.”
Baconian method – Wikipedia

I knew more about what the word actually means when I was 8 years old than you seem to know as an adult.

Last edited 1 month ago by Nicholas McGinley
PCman999
Reply to  Nicholas McGinley
April 19, 2022 3:23 pm

Best comment I read today.

Seeing how difficult Bacon’s method is, it’s no wonder that science in general, not just climate scientology, has a reproducibility crisis. Many studies have shown that a great deal of peer-reviewed papers are not reproducible, and hence suspect.

Nicholas McGinley
Reply to  PCman999
April 20, 2022 10:25 am

I am not accustomed to saying anything with certainty after only one or two observations.
— Andreas Vesalius, (1546)

b.nice
Reply to  Duane
April 19, 2022 12:53 pm

Obviously you have had little to ZERO interaction with actual “models”

The models used in engineering undergo constant validation, and are build from solid provable engineering theory

Climate models have never been validated.. they are nothing more than glorified computer games. They are build from speculation and presumption with only a passing wave at actual physics and data.

They are NOT science.

PCman999
Reply to  b.nice
April 19, 2022 3:27 pm

Very true – I can design and run a nuclear reactor simulation in the CATHENA software and it will give results comparable to a real reactor – even if I put in a design that is totally different than the CANDU reactor it was designed for. That’s because it’s been tested to death and deals with a small, well controlled system, not a chaotic planet!

PCman999
Reply to  Duane
April 19, 2022 3:18 pm

Duane get over yourself – WUWTers use ‘models’ as shorthand for ‘typical climate science activist’s pride, biases and ignorance encapsulated in a shell of sketchy computer programming, that gives undeserved credence to disastrous political policies, that seek to pound humanity into a green pulp of submission.’

Oh, and you can throw in disease spreading models into the same category.

RickWill
Reply to  Duane
April 19, 2022 4:07 pm

The term “Climate Model” uses the word “model” inappropriately. The word “fantasy” would be better. They are actually “Climate Fantasies”. They do not model anything. They bear no relationship to physical processes. They all create matter from nothing. They all show open ocean water exceeding 30C surface temperature. They somehow get ocean surface heat down to 2000m in a matter of decades.

So climate “modellers” abuse that term. At best they could be described as programmers and not very good ones.

Newminster
Reply to  RickWill
April 20, 2022 2:37 am

I seem to recall one of the scientivists admitting (15 or so years ago) that they didn’t base their work on real-world data but on the models.
I’m sure the quote will still be lurking somewhere on the internet.

Nicholas McGinley
Reply to  Newminster
April 20, 2022 10:33 am

The methodology they use involves basing real world data on the models.
The data as measured does not support their dogmatic preordained views, and so the data is changed until it does.
This is, again, the opposite of what an actual scientists is supposed to do.

Screen-Shot-2016-11-21-at-9.26.17-AM.png
Nicholas McGinley
Reply to  Duane
April 20, 2022 10:45 am

” I get it that the WUWTers here like to denigrate all models as a sort of knee jerk exercise, but that is nothing but know-nothingism and Luddism, or celebrating ignorance and lack of understanding as a virtue.”

Exactly wrong.
Skepticism is the essence of the scientific method.
Getting an idea fixed into one’s mind and letting that notion guide all future thoughts and ideas is true know-nothingism.

As for the models and the way they are used by warmistas, let’s look outside the WUWT commentariat for some opinions:

“Professor Humlum said:
“A year ago, I warned that there was great risk in using computer modelling and immature science to make extraordinary claims. The empirical observations I have reviewed show very gentle warming and no evidence of a climate crisis.”

GWPF director, Dr Benny Peiser said:
“It’s extraordinary that anyone should think there is a climate crisis. Year after year our annual assessment of climate trends document just how little has been changing in the last 30 years. The habitual climate alarmism is mainly driven by scientists’ computer modelling rather than observational evidence.””

2021 State of The Climate Report: Empirical Observations Show No Sign of ‘Climate Crisis’ – ‘Snow Cover Stable, Sea Ice Levels Recovering, & No Change in Storm Activity’ – Watts Up With That?

Which is exactly what I have always said, for years now.
Specifically:

“…climate alarmism is mainly driven by scientists’ computer modelling rather than observational evidence.”

“there was great risk in using computer modelling and immature science to make extraordinary claims.”

You stated your belief that the author “never said that vegetation causes warming”, which is false.
He plainly said exactly that it does and has.

This would cause a rational person to change their mind.
I wonder if new information will cause you to change yours?

Last edited 1 month ago by Nicholas McGinley
Chris Nisbet
April 18, 2022 11:09 pm

I suppose Alarmists will tell us it’s another one of these dreaded +ve feedbacks – warm temperatures cause more vegetation, which causes higher temperatures…
A question occurs to me. Is all this tree planting to offset CO2 emissions and therefore stop the planet from overheating actually warming the planet?
Maybe the NZ government’s failure to deliver on its policy to plant 1 billion trees was actually intentional – they knew it would overheat the planet.
Maybe it’s _good_ warming, so doesn’t count?
And what will happen to this study once this part of the historical temperature record is adjusted?

This climate change nonsense is quite difficult to make sense of.

Old Man Winter
Reply to  Chris Nisbet
April 19, 2022 1:28 am

Interesting point. The Black HIlls burned, as did Jellystone. in the drought year of ’88. In May 1990, I
went to the Black Hills & saw many Black Hills pines- many of which were planted ~75 yrs earlier-
had burned. The rangers, worried about loss of water flow in the trout streams, got a good surprise.
The flow had increased as the new grass used less H2O than did the trees.

One factor I don’t know how it affects this is that grass isn’t as dark as the pines but is hotter than
forests with their shaded canopy, which acts as a buffer between darker tree tops’ temps & ground
temps below. Grass is open with nothing to stop evaporating moisture from rising just like moisture
evaporating from tree tops. Any ideas?

https://wattsupwiththat.com/2017/05/22/cutting-the-grass/

Nicholas McGinley
Reply to  Old Man Winter
April 19, 2022 2:27 am

Go to the forest when it is night, and you will find it is warmer by far that out in the open.
And not as hot during the day.

As for stream flow, it is not as simple in that regard either.
By several separate mechanisms, trees increase the amount of water that is retained in the soil and subsoil layers, thus evening out stream flow.
Not as much stream flow with trees when measured after rain, but more stream flow when it has not rained recently.
Trees retain water, net net.
One cannot just go by one day and have a look at a stream and make a sweeping conclusion based on that moment or that day.
Ditto temperature.

Last edited 1 month ago by Nicholas McGinley
Christina Widmann
Reply to  Chris Nisbet
April 19, 2022 1:40 am

You, Sir, are raising the important questions. Did the Roman Warm Period end because they had cut down all the oaks for ships and let their goats graze the Mediterranean clean? Could we stop ClimateChange™ by cutting down the Amazon?

I’ll make my small contribution today by eating some goat cheese. Keeping the Mediterranean treeless, that’s me.

william Johnston
Reply to  Chris Nisbet
April 19, 2022 6:52 am

Projections, predictions and theories ae fine until one starts basing major decisions on them. Excuse me while I go rearrange my sock drawer.

Nicholas McGinley
Reply to  william Johnston
April 19, 2022 11:08 am

We would all be far better off if the warmistas did something useful with their time, such as rearranging socks.

fretslider
April 19, 2022 1:08 am

“ a set of experiments with a climate model “

Can someone tell this numpty that a model run is not an experiment, it’s a mind game

Paul Homewood(@notalotofpeopleknowthat)
Editor
April 19, 2022 1:24 am

Sounds like Father Dougal’s Dreams v Reality!

https://www.hairybaby.com/dreams-vs-reality

Oldseadog
April 19, 2022 2:10 am

Chicken and egg.
Did the warming cause the increase in vegitation or did the increasing vegitation cause the warming?

RLH(@richardlinsleyhood)
Reply to  Oldseadog
April 19, 2022 3:28 am

Eggs existed before chickens.

Gordon A. Dressler
Reply to  RLH
April 19, 2022 7:46 am

Sure . . . just consider the primordial “cosmic egg”.

QED.

Ron Long
Reply to  Oldseadog
April 19, 2022 6:01 am

Oldseadog, here’s a clue to your question: people put plants in greenhouses to warm the air up (according to Mr. Science). I was born sarcastic.

jeffery p
Reply to  Oldseadog
April 19, 2022 6:54 am

It’s all climate change now. If a comet slams into the earth and blocks the sun for years, the problem is climate change, no matter the root cause.

Dave Fair
Reply to  Oldseadog
April 19, 2022 9:39 am

Or did the loss of the vast ice sheets result in more Northern Hemisphere water vapor and rainfall in the desert areas?

Mark Twain said: “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”
Add in unvalidated models and one gets CliSciFi. I assume Mark Twain would have had alot of fun with post-normal science.

Nicholas McGinley
Reply to  Oldseadog
April 19, 2022 11:11 am

Two miles thickness of ice had to melt before any vegetation could grow where the ice sheets were sitting.
And I am pretty sure that the Sahara was not as hot when it was covered in grasses and trees, and dotted with lakes and ponds, and crisscrossed with streams and rivers.

Last edited 1 month ago by Nicholas McGinley
Nicholas McGinley
Reply to  Nicholas McGinley
April 19, 2022 11:13 am

Although it was likely somewhat warmer at night in the colder parts during the low sun seasons.

Michael in Dublin
April 19, 2022 3:18 am

I knew it. Man is responsible for global warming. Prehistoric man with this wood fires, instead of using solar or wind power, set the problem in motion. Perhaps we all need to go vegetarian because then we would not need to have fires to cook meat and fish. Just think how clean our air will be and no plastic pollution on the land or in the sea. We could all be noble savages living in our utopia where we would not need money. We can simply barter. Just image a world without a single billionaire or millionaire. Just imagine no banks, factories, mines, distracting electronic devices, no hideous skyscrapers and congested highways, no cars and planes and ships. Best of all we would not need politicians and activists.

william Johnston
Reply to  Michael in Dublin
April 19, 2022 6:54 am

Why did you list things in reverse order?

Michael in Dublin
Reply to  william Johnston
April 19, 2022 11:22 am

Because alarmists put the cart before the horse thinking that this will give them extra horse power.

Peta of Newark
April 19, 2022 3:21 am

<chuckles to self>
We’re getting there. slowly
If the use of models is how it’s done, the so be it.

How long before it is properly recognised that (the belligerent, war-mongering, physical and thus mental wreck that was) King Henry 8 of England, by cutting the forest of England and indirectly that of NW Europe, caused the Little Ice Age

And Henry was like that simply because of his addiction to sugar
Deserts are cold places and it exactly the sort of people like Henry that create them.

Now, go outside and look around you, not at the trees or the weather/climate or The Computer or what Sputnik says – just look at the people you see to predict the future of everything.

Maybe start with the train-wreck described in the adjacent story today (windmill subsidies)
Also glance in the direction of BoJo, a sugar-induced wreck massively exacerbated by alcohol. Or Brandon, what you get from decades of sugar-abuse

Or all the pregnant males you see.
That belly fat creates Oestrogen, hence why the pregnant boys also grow boobs and why they ‘go off’ the idea of making babies – it over-rides Tosserone.
Likewise for girls
Testosterone is needed by both parties to initiate baby-making and the current lack of babies is caused by that = a surfeit of Oestrogen, not any surfeit of richness or intelligence.
Quite the opposite in fact – dumb people don’t breed.
and they destroy everything they touch

Last edited 1 month ago by Peta of Newark
H.R.
Reply to  Peta of Newark
April 19, 2022 4:53 am

Peta: “[…] dumb people don’t breed.”


You’re off the mark there, Peta. It seems people are getting dumber because dumb people breed, prolifically, and generally with other dumb people. Western governments subsidize breeding by paying for the upkeep of offspring.

It used to be, before ‘elf & safety, dumb people didn’t live very long. Life was nasty, short, and brutish and particularly the short part dominated if you were stupid.

The agrarian society that dominated for most of history had people producing as many children as possible to help on the farm and to cover the loss of the dumb ones that got themselves k!lled doing stupid things while working on the farm. (I’m not overlooking disease and plague. That eliminated some of the kids regardless of intelligence.)

Our modern society allows a lot more of the dumb to survive and to breed than in days of yore. And since they are no longer getting k!lled in farm accidents, we have to find someplace in society for the stupid ones.

That explains the explosive growth in government employees, politicians, climate activists, and other useful idiots. None of those positions require much in the way of brain power. And they breed.

/semi-serious rant

fretslider
Reply to  Peta of Newark
April 19, 2022 6:41 am

“ dumb people don’t breed.”

Can you explain the ever popular Darwin awards?

Dave Fair
Reply to  Peta of Newark
April 19, 2022 9:42 am

Peta, I deny that I have toxic masculinity. I simply have testy cals.

meab
Reply to  Peta of Newark
April 19, 2022 11:26 am

Another one of your idiotic posts, Peta, that would have benefited from 2 minutes of research on the web.

Henry 8 cut down approximately 100,000 trees to make ships. There are 3 billion trees in the U.K. so Henry 8 cut down 0.0033% of the trees. Tiny. He cut these trees down in the 1530s. There are various estimated times for the start of the Little Ice Age;

  • 1250 for when Atlantic pack ice began to grow
  • 1275 to 1300 for when the radiocarbon dating of plants shows that they were killed by glaciation
  • 1300 for when warm summers stopped being dependable in Northern Europe
  • 1315 for when rains and the Great Famine of 1315 to 1317 occurred.

By 1650, glaciers were advancing globally.

Amazing how cutting such a tiny fraction of trees down in a tiny country in the 1530s caused an ice age that most likely started 250 years before.

Peta, seriously, stop beclowning yourself. Do 2 minutes of research before you post.

AndyHce
Reply to  meab
April 20, 2022 10:43 pm

But did Peta demonstrate that mountain ranges, ocean currents, atmospheric zonal currents, and a few dozen other large factors have nothing to do with climate?

April 19, 2022 3:50 am

No models needed. Straight forward analysis of atmospheric temperature and CO2 concentration clearly shows that temperature determines the rate of generation of CO2. The reverse is not possible because a rate of change does not define a level. A rate of change of say 2 ppm per annum could be from zero to two ppm or 1002 to 1004 ppm of CO2 or any pair of numbers differing by two.
This is why CO2 change always follows after temperature change. The local temperature maximum coincides with the maximum rate of increase in CO2 which of necessity precedes the local CO2 maximum.
Doesn’t anybody bother to look at the real data these days ?

saveenergy
Reply to  Bevan
April 19, 2022 4:04 am

“Doesn’t anybody bother to look at the real data these days ?”

No, it just complicates the political narrative !!

Graemethecat
Reply to  saveenergy
April 19, 2022 5:10 am

No, it just complicates the political narrative !!

No, it contradicts the political narrative!

Peter W
Reply to  Graemethecat
April 19, 2022 9:03 am

Details, details, . . . . .

Reply to  Peter W
April 19, 2022 6:00 pm

Peter W: Please see my web site at https://www.climateauditor.com

AndyHce
Reply to  saveenergy
April 20, 2022 10:45 pm

Once the religions precepts are determined, trying to bring other factors into the story is always frowned upon.

Nicholas McGinley
Reply to  Bevan
April 19, 2022 11:30 am

Also, when interglacials begin and temps warm rapidly and melt the ice, CO2 is at a minimum value, and terrestrial vegetation is at a minimum.
Then, when the interglacial ends, CO2 has risen to the maximum value of the interval, and vegetation is likewise near or maybe even at a maximum.

So obviously, whatever is causing the temperature changes happens first, and it happens regardless of CO2 or vegetation.
As you say, both of these respond to the temperature change (and likely also increasingly humid conditions).

If any feedback between lower CO2 and lower vegetation kept making it ever cooler, there would be no interstadials.
And if more CO2 and more vegetation caused ever warmer temps within an interstadial, the interstadials would not end, it would just keep getting warmer.

So obviously, whatever is causing the swings in temp from stadial to interstadial, it is vastly more powerful than any possible effects of the CO2 and vegetation levels.

Ice core CO2 not in control of temp.jpg
Last edited 1 month ago by Nicholas McGinley
Rud Istvan
April 19, 2022 6:27 am

It is obvious that green plants warm. Simple proof. When the leaves turn colored and fall off it gets colder. /s (something about cause and effect)

Tom Gasloli
April 19, 2022 7:06 am

Isn’t it amazing how many things can be proved by a computer model! And it is so much easier than doing all that tedious science stuff. 😃

Gordon A. Dressler
April 19, 2022 7:44 am

From the above article: “. . . according to new model simulations published April 15 in Science Advances.”

Science advances (!) mostly by objective data measurements that confirm or falsify postulated theories, less so much just by “model simulations.”

Reference: the scientific method.

Andy Pattullo
April 19, 2022 8:15 am

Obviously the problem of climate changing won’t be fully solved till all life on Earth is exterminated. Or at least there will be no one left then to complain about the climate.

Duane
April 19, 2022 8:25 am

It makes perfect sense that climate both affects vegetation and that vegetation affects climate. This is not a warmunist fantasy, it’s real scientific understanding.

Vegetation affects a number of parameters that in turn affects local and regional climates:

  1. Albedo – absorbs more sunlight than bare rock.
  2. Specific heat of the planet’s surface (vegetation has far lower specific heat than does liquid water, and far higher specific heat than does bare rock or soil). The lower the specific heat, the greater the change in temperature of the mass per unit of solar energy absorbed … or, another way to put it is that the higher the specific heat the more a substance acts as an energy storage mechanism and thus tends to stabilize temperatures.
  3. Respiration – green plants absorb sunlight and fix carbon dioxide from the air to create plant mass, and emits oxygen
  4. Evapotranspiration – the process of plants emitting water vapor to the atmosphere via uptake from the ground surface, which in turn makes the atmosphere more humid
  5. Reduces runoff velocities, storing more precipitation in the surface soils improving hydration for plants and allowing greater evapotranspiration.
  6. Dead vegetation tends to sequester carbon and other minerals into surface soils, bogs, and eventually into geologic formations (i.e., as peat, oil, and gas).

What the warmunists don’t get at all is their fallacious contention that there is one and only one parameter that serves as the earth’s climate control, and that is atmospheric carbon dioxide. Their anti-scientific attitude refuses to acknowledge the long-recognized complexity of the Earth’s system. There are hundreds, perhaps thousands of parameters that affect local and regional and worldwide climate, all providing feedback to each other, and always collectively trying to maintain stability and avoid radical changes.

Last edited 1 month ago by Duane
Rob_Dawg
April 19, 2022 10:11 am

Forests are warmer than glaciers. Who knew?

Nicholas McGinley
Reply to  Rob_Dawg
April 19, 2022 11:16 am

Which happened first, the ice melted or the trees grew?

Nicholas McGinley
Reply to  Rob_Dawg
April 19, 2022 11:48 am

BTW Rob, I am not disagreeing with you at all.
Just sayin’.

Rob_Dawg
Reply to  Nicholas McGinley
April 20, 2022 8:01 am

No problem. Silly university studies beget silly replies like mine.

matt
April 19, 2022 11:52 am

No No No! It was people what done it. Me in particular. I am so important that even my flatulence changes the world.

H.R.
Reply to  matt
April 19, 2022 5:17 pm

Remind me never to pull your finger.

RickWill
April 19, 2022 4:19 pm

Who would have thought that trees are a temperature control mechanism. Able to make cool places warmer and hot places cooler.

But climate fanatics believe they can do better. Chop down all the trees and replace them with wind energy extractors to create balmy weather.

I can see some potential here for unintended consequences.

Burl Henry
April 19, 2022 4:42 pm

COMPLETE NONSENSE!

Reply to  Burl Henry
April 19, 2022 8:57 pm

How Dare You!!

Walter Sobchak
April 21, 2022 8:39 am

“updated simulations from an important climate model”

In other words he modded the video game. Video games are not science.

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