Mediterranean Sea was 2 degrees hotter during Roman Empire

From the Archaeology News Network

The greatest time of the Roman Empire coincided with the warmest period of the last 2,000 years in the Mediterranean, according to a study published in the journal Scientific Reports. The climate conditions derived progressively towards arid conditions and later colder ones coinciding with the historical fall of the empire, as stated in the new study, whose principal researchers are Isabel Cacho, Giulia Margaritelli and Albert Català, from the Faculty of Earth Sciences and the Consolidated Research Group on Marine Geosciences of the University of Barcelona. The study also counts on the participation of the experts from the Research Institute for Geo-hydrological Protection of the National Research Council (CNR-IRPI), the National Institute of Marine Sciences (CNR-ISMAR), the University of Campania Luigi Vanvitelli and the University of Perugia in Italy.

(a) Bathymetric map of the central-western Mediterranean Sea. Red triangle: location of SW104 ND11 core; red circles: marine records used for the comparison; (b) Bathymetric map of the Sicily Channel showing surface oceanographic circulation and core location. Black lines follow the path of surface water circulation. Major currents are illustrated [Credit: Margaritelli et al. 2020]

Previous studies had related the fall of the Roman Empire to some natural factors (climate change, volcanic eruptions, etc.). With a large-scale regional view, the study provides high resolution and precision data on how the temperatures evolved over the last 2,000 years in the Mediterranean area. “For the first time, we can state the roman period was the warmest period of time of the last 2,000 years, and these conditions lasted for 500 years”, notes Isabel Cacho, professor at the Department of Earth and Ocean Dynamics of the UB.

The Mediterranean Sea is a semi-closed sea –extremely vulnerable to modern and past climate changes – with a strategic location. Home to many civilizations over the years –with a tradition for historical and archaeological studies – Mare Nostrum is a model to study the periods of climate variation and climate potential influence in civilizations.

In particular, the Roman Empire period is hard to study, “since it coincided with important cultural changes that took place around the Mediterranean. The study of the climate of the past is now the only tool to analyze the dynamics of the climate System of the Earth in different conditions from the current ones, and it is essential to test the validity of the mid and long term prediction models”, note the experts Giulia Margaritelli (also member of the CNR-IRPI) and Fabrizio Lirer (CNR-ISMAR).

The study identifies for the first time a warming phase which is different during the Roman period in the Mediterranean area and is focused on the reconstruction of the sea surface temperature (SST) over the last 5,000 years.  These new records were correlated to data from other areas of the Mediterranean (Alboran Sea, Menorca basin and Aegean Sea) to show a regional signal of the basin to identify the Roman period (1-500 AD) as the warmest period of the last 2,000 years, 2ºC warmer than the average values at the end of the century. The experts also comment on the impact of the rainfall regime during this period –marked by a great regional variation of the most wet and arid phases- in the evolution of the Roman Empire.

Comparison of the Sea Surface Temperature (SST) records from Sicily Channel (thick dark blue line), Alboran Sea (thick light blue line), Minorca Basin (thick red line) and Aegean Sea (thick dark and light green lines) expressed as SST anomalies in relation with the reference period from 750 BCE to 1250 CE (the only period shared by all the records) in order to better compare the amplitude of the changes across the Mediterranean Credit: Margaritelli et al. 2020]

According to the authors, this phase coincides with the development of the expansion of the Roman Empire, which suggests a potential relation between favouring climate conditions and the change into the great empire founded by Octavius Augustus in 27 BC. According to the hypotheses of the authors, a climate transition from wet to arid conditions could have market its following decline.

Read the full article here.

HT/John T

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Charles Boritz
July 27, 2020 6:14 am

Error in final sentence: market should likely be marked…

July 27, 2020 6:19 am

The more I read about past climate changes, the more I am convinced that the current climate is unremarkable. The real deniers are the ones who deny natural variability.

In order to put the Roman climate into context I looked up the wiki page for the Sahara Desert. It seems that the Sahara has undergone many changes between being green and verdant to being a desert. That lends credibility to the reconstruction showing the Roman climate also going from wet to arid.

Phil Rae
Reply to  commieBob
July 27, 2020 6:36 am

Having spent a fair amount of time driving around in the Sahara, I always found it fascinating to come upon large swathes of petrified trees that appear intermittently as the sands shift with the wind. The Sahara had lots of trees once upon a time.

Reply to  Phil Rae
July 27, 2020 7:23 am

Phil Rae says :

” …. come upon large swathes of petrified trees that appear intermittently as the sands shift with the wind. The Sahara had lots of trees once upon a time.
Did any “holed” tanks ever appear out of the sand ? The Sahara also had lots of tanks once upon a time.

Reply to  sendergreen
July 27, 2020 7:57 pm

“sendergreen July 27, 2020 at 7:23 am

Did any “holed” tanks ever appear out of the sand ? The Sahara also had lots of tanks once upon a time.”

And the relation to climate is?
Talk about red herring logical fallacies…

Reply to  ATheoK
July 27, 2020 8:34 pm

I’m a historian by training, most of it military … I had a genuine interest in whether the commenter Phil Rae had seen any war detritus in the Sahara. Breaking tanks was once a very close relative’s primary executive job. As for the climate connection … it’s still hot there two generations later.

Ben Vorlich
Reply to  commieBob
July 27, 2020 11:53 am

Didn’t some Roman, Herodotus?, write about “that part of Libya is much fuller of wild beasts and more wooded than the country of the nomads.”?

Hannibal got his elephants locally too I think

John Tillman
Reply to  Ben Vorlich
July 27, 2020 12:26 pm

Herodotus (c. 484-25 BC) was Greek, to whom “Libya” meant all North Africa west of the Nile.

Yes, Carthaginian armies relied on the extinct North African elephant.

Reply to  John Tillman
July 27, 2020 3:58 pm

“Yes, Carthaginian armies relied on the extinct North African elephant.”

No. Carthaginian armies relied on the then extant North African elephant.

As that elephant is now extinct, so is Carthage. 🙂

John Tillman
Reply to  Brendan
July 27, 2020 7:39 pm

The “now” in “now extinct” was implied.

John Tillman
Reply to  commieBob
July 27, 2020 7:47 pm

The fact that ancient seaports are now far inland is always blamed upon “silting”. But the fact is that sea level was higher during the Minoan, Roman and Medieval Warm Periods than now. Also the Holocene Climate Optimum and Egyptian WP, but there were fewer ports then.

Rome’s old port is now some two miles from the sea, for instance.

Richard (the cynical one)
July 27, 2020 6:33 am

These facts are so inconvenient. They need to be adjusted. Perhaps with a hockey stick. Anybody there in East Anglia up to the job?

Randle Dewees
Reply to  Richard (the cynical one)
July 27, 2020 8:39 am

There is a Winston, somewhere, assigned the task.

Steven Mosher(@stevemosher)
Reply to  Richard (the cynical one)
July 27, 2020 5:13 pm

err, it already has been adjusted. you dont understand proxies

Jeff Alberts
Reply to  Steven Mosher
July 27, 2020 10:55 pm

You don’t understand sarcasm.

Peta of Newark
July 27, 2020 6:34 am

Of course it was.
The Romans, using Greek slaves, turned what was forest, green fields and gardens into the desert that we all know and love today.
What rain that fell on the wasted (low albedo) dirt was of course warmer and flowed into the sea. warming it up.
(Green vegetation has an insanely high albedo, even higher that that of ‘old’ ice/snow)
The rain which still fell created flash floods (typical of desert climes) thus stranding sea-ports miles inland.
But then, just like in a rainforest – what creates what? If the forest disappears, so does the rain andis exactly what happened.

Exactly what’s going on now on what’s left of the ‘green spaces’ Read= ‘Farmland’

‘course nobody wants to know – with VERY good reason.
When the current desertification rampage nears completion it’ll make the worst ‘worse-than-we-thought’ climate alarmist alarms look like a walk in the park

Reply to  Peta of Newark
July 27, 2020 7:25 am

Say what?
I read that twice trying to find some indication that it was sarcasm.

The Sahara drying up is what caused the Egyptians to congregate around the Nile, which is what got Egypt started as a country. This was over 5000 years ago. Almost 3 millennia prior to the formation of the Roman Empire.

As to your rant about Farmland, I couldn’t figure out what your point is in the first place.

Bob boder
Reply to  MarkW
July 27, 2020 10:11 am

I was assuming this was all sarcasm, Peta can’t actually be serious.

John Tillman
Reply to  MarkW
July 27, 2020 12:36 pm


The 4.2-kiloyear BP aridification event, one of the most severe climatic fluctuations of the Holocene, defines the beginning of the current Meghalayan age in this epoch. It definitely ended the drying up process of the previously verdant Sahara, begun six to five thousand years ago. The two cold snaps of the Younger Dryas and the 8.2 Ka event briefly interrupted the roughly ten millennium moist interval.

Reply to  Peta of Newark
July 27, 2020 9:31 am

@Peta of Newark
Do you honestly believe that?
Do The Math. Calculate how many Trillion gallons of water would have to be heated to and for how many decades at an appreciable much higher temperature than the Med. to heat it 2 degrees. Worse. the surface area of the “farmland” is infinitesimal compared to the Med.

Reply to  Uzurbrain
July 27, 2020 10:48 am

Uzur, to belabour the obvious….
SST= Sea SURFACE Temp….takes a lot less Q than heating the whole sea to depth. A couple of sunny weeks in the summer appreciably warms water body surface temps.

Reply to  DMacKenzie
July 27, 2020 12:45 pm

Which points to the obvious – SUN heated the Med. Not rivers.

Reply to  Peta of Newark
July 27, 2020 11:48 am

There must be a reason most plants reflect green light. Somehow I think they don’t like it. That’s why it is cooler under a tree so a lot of trees together should have a cooling effect.

Steve Keohane
Reply to  Robertvd
July 27, 2020 2:01 pm

There was a posting here some years ago based on this paper. “From Canada to the Caribbean: Tree leaves control their own temperature” June 11th, 2008

Hopefully this link still works, it is from the bottom of the word doc I have.

Loren C. Wilson
Reply to  Robertvd
July 27, 2020 4:38 pm

The chlorophyll that most plants use to convert CO2 and water into carbohydrates and oxygen absorbs red and blue light. The green light is reflected and not used.

tsk tsk
Reply to  Loren C. Wilson
July 27, 2020 5:30 pm

Which is kinda odd given that’s peak solar output. I presume that has something to do with the specific chemistry involved.

July 27, 2020 6:41 am

It gives the imprint of cyclic nature of climate change

John Tillman
July 27, 2020 6:50 am

Tibi grata!

The divergence of the Sicilian Channel and Aegean Sea before c. 1000 BC is interesting. The Adriatic is deep and Aegean shallow. The Aegean broke through into the Black Sea around 5600 BC.

Northern Hemisphere ice sheets had melted back to about their present positions by the Holocene Climatic Optimum, c. 6000 to 3200 BC, after the cold snap at 6200 BC, caused by the last cold, fresh water surge into the North Atlantic. Peak Holocene warmth had also been reached c. 7000 BC, often considered part of the HCO, interrupted by the 8.2 Ka Dryas-like event.

Early Aegean balminess coincides well with the Egyptian and Minoan Warm Periods, both generally toastier than the Roman, which was warmer than the Medieval and Modern WPs. The trend is not our friend.

John Tillman
Reply to  John Tillman
July 27, 2020 6:52 am

Sorry. Meant Ionian Sea, not Adriatic, which is a mostly shallow gulf. Its northern and central reaches are dry land during glaciations.

July 27, 2020 7:22 am

I have borrowed heavily from an Aeon piece written in 2017 called
‘How climate change and disease helped the fall of Rome’ that the Smithsonian magazine ( says has now been republished under Creative Commons. Attribution at the end of this comment.

In the middle of the second century, the Romans controlled a huge, geographically diverse part of the globe, from northern Britain to the edges of the Sahara, from the Atlantic to Mesopotamia. The generally prosperous population peaked at 75 million. Eventually, all free inhabitants of the empire came to enjoy the rights of Roman citizenship.

Five centuries later, the Roman empire was a small Byzantine rump-state controlled from Constantinople, its near-eastern provinces lost to Islamic invasions, its western lands covered by a patchwork of Germanic kingdoms.
Trade receded, cities shrank, and technological advance halted. Despite the cultural vitality and spiritual legacy of these centuries, this period was marked by a declining population, political fragmentation, and lower levels of material complexity.

However during this time politicians and rulers of Rome became more and more corrupt; Infighting and civil wars within the Empire were rife. [Echos of today perhaps]

…new evidence has started to unveil the crucial role played by changes in the natural environment. The paradoxes of social development, and the inherent unpredictability of nature, worked in concert to bring about Rome’s demise.

Climate change did not begin with the exhaust fumes of industrialisation, but has been a permanent feature of human existence. Orbital mechanics (small variations in the tilt, spin and eccentricity of the Earth’s orbit) and solar cycles alter the amount and distribution of energy received from the Sun. And volcanic eruptions spew reflective sulphates into the atmosphere, sometimes with long-reaching effects. …
But climate change per se is nothing new.

The end of this lucky climate regime did not immediately, or in any simple deterministic sense, spell the doom of Rome. Rather, a less favourable climate undermined its power just when the empire was imperilled by more dangerous enemies – Germans, Persians – from without. Climate instability peaked in the sixth century, during the reign of Justinian. Work by dendro-chronologists and ice-core experts points to an enormous spasm of volcanic activity in the 530s and 540s CE, unlike anything else in the past few thousand years. This violent sequence of eruptions triggered what is now called the ‘Late Antique Little Ice Age’, when much colder temperatures endured for at least 150 years. This phase of climate deterioration had decisive effects in Rome’s unravelling. It was also intimately linked to a catastrophe of even greater moment: the outbreak of the first pandemic of bubonic plague.

See for the full story complete with nods to modern fiction of ‘climate change’.

Looks like the catastrophic end of the Roman period with its rise during those evident warmer times was halted by the cooling climate hence less food and therefore generally less fit population that has a greater susceptibility to nasty diseases. Are there political and climate cycles working concert?

The past rarely repeats but often rhymes.

John Tillman
Reply to  tom0mason
July 27, 2020 10:08 am

The decline of Rome also coincided with pandemics, both in the Western and Eastern Empires.

Two viral, probably smallpox (from a virus of African rodents, such as gerbils) and measles (also zoonotic, as closely related to rinderpest virus). So far, smallpox (DNA) and riderpest (RNA) are the only eradicated viruses:

The Y. pestis bacterium, of Black Death infamy:

The worsening climate also drove barbarian invasions from the north (Germanic tribes), east (Huns and Alans) and south (Arabs).

Colder is definitely deadlier, both directly and indirectly.

Bob boder
Reply to  John Tillman
July 27, 2020 10:16 am

The worsening climate drove huge waves of barbarians from the north that previously had flourished because of the warm climate.

This pattern is seen over and over in Europe, Central Asia and China. Continual climate change is the mostly likely source for this pattern.

Reply to  Bob boder
July 27, 2020 3:32 pm

Bob you clearly have not understood your history. It was the white male that is responsible for climate change and slavery. Of course Trump exasperates the problem 😉

Mumbles McGuirck
Reply to  tom0mason
July 27, 2020 11:38 am

” Infighting and civil wars within the Empire were rife. [Echos of today perhaps”

I’m willing to bet Rome’s Vandals were less ‘woke’ but bathed more often.

Pat from kerbob
Reply to  tom0mason
July 27, 2020 6:42 pm

It’s funny but Islam only exists because f climate change and the plaque.
The Byzantines and Persians tired themselves out fighting each other while the plague decimated both peoples, leaving no opposition when Mohammad swept up from the peninsula.
Without those factors unleashing him, Islam would have just been another footnote of history, a failed personality cult
Like Obamaism

Pat from kerbob
Reply to  Pat from kerbob
July 27, 2020 6:46 pm

Plague not plaque
Stupid autocorrect

Although I imagine fetal hygiene was not very good

John Tillman
Reply to  Pat from kerbob
July 28, 2020 11:39 am

The Holy Land didn’t have time to recover from its Sassanian capture in AD 614. The Persians massacred an estimate 90,000 Christians in Jerusalem alone. Byzantine forces under Emperor Heraclius retook the province os Palaestina Prima in 628, but the region remained devastated.

But in 632, Muslim Arab armies invaded both Sassanian Iraq and the Byzantine Levant. The Arabs defeated Heraclius’ attempt to regain lost territory in 636.

I don’t know to what extent plague contributed to the Persian and Greek defeats. The Justinian Plague in the previous century had affected Arabia as well as Byzantium and Persia.

July 27, 2020 7:24 am

The greatest time of the Roman Empire coincided with the warmest period of the last 2,000 years in the Mediterranean, according to a study published in the journal Scientific Reports.

There is no coincidence, but it’s the consequence of the warm period.
They are always looking out of the wrong perspective while producing such studies.

Pat from kerbob
Reply to  Krishna Gans
July 27, 2020 6:45 pm

Yes, just as it was the Holocene optimum got human civilization started.

Or, the worst thing ever depending who you listen to, no wonder the climactically insane hope for ice ages, imagine all the people that would decimate.

Jeff Alberts
July 27, 2020 7:32 am

I’m guessing that the thin blue lines are error bars. Not sure what the thin dotted line is supposed to represent.

Gary Pearse
July 27, 2020 7:33 am

“and later colder ones coinciding with the historical fall of the empire,”

Nothing wrong with this statement here, but they press on this as if it is a correlation through the rest of the article. They even have a model that seeks this correlation. I can see a couple of degrees cooling (after the warming period) being huge in northern Europe, but the Mediterranean? It’s even a lot colder than the Italians are experiencing right today in the heights of our puny warming period (as it’s turning out to be).

Climate was important but my bet is on social rot, useful idjits and the Huns getting the upper hand.

John Tillman
Reply to  Gary Pearse
July 27, 2020 12:03 pm

Worsening climate in Eastern Europe and Western Asia may have driven the Huns westward.

There definitely was social rot, invasion and low reproduction, but the Empire actually managed to revive from near demise during the 3rd Century Crisis, c. AD 235-84, to survive nearly 200 more years in the West, and 1200 more in the East:

July 27, 2020 7:43 am

It is likely no coincidence that the incursions of the “Gauls” into the Italian peninsula in ca 390 BC and then the combined “Germans” and Gauls ca 110 BC took place when they did. Nor might it be a surprise the Civil Wars (so called Servile Wars) took place when they did…

If the climate was cooling sufficiently prior to the turn-around and warming which may have coincided with the beginning of the Principate, that cooling may well have been enough to stress the Republican economy to the point of breakdown…across the Med.

If it were that, then how much more is it likely to have made the climate North of the Alps very unpleasant and caused mass migration to gentler climes? The Cimbri recounted to Sulla that they had been driven from their homeland on the Jutland Peninsula by incursion of the sea and widespread flooding which had poisoned their pasture and land. Sounds like a massive storm surge in the North Sea…

Equally at the other end of the Roman Optimum from perhaps 350 AD onward, the deterioration of a warm climate almost certainly led to the same pressures on the Germanic tribes, and behind them to the East, the Steppe Nomads like the Huns, Sarmatians, Alans. Cooler is drier; and unpleasant…so head for the warmer, easier lands around the Med; even if they were no longer as warm and easy as they had been.

Only certain fools would deny there is a certain rhythm to mass migrations in the ancient Fertile Crescent/Med/European world; and that they are traceable right back to the beginning of recorded history. They are also, at least arguably (because precise dating can be debated for a number of reasons), fairly regular.

One day a multi-disciplinary approach will identify what the semi-regular driver/s were and doubtless still are….

July 27, 2020 8:23 am

Yeah but what have the Romans ever done for us?

Reply to  Mr.
July 27, 2020 8:51 am

Remembering school and courses in Latin, not so much good 😀
On he other hand, cervesa…… 😀

Reply to  Krishna Gans
July 27, 2020 11:03 am

“Amo, amas, amat, amamus . . .”
Recited robotically by 30 sweaty, stinky boys in an oppressively hot classroom after a lunchtime game of cricket.
Not as bad as choir practice though. There we also had to suffer Tubby Thompson’s farts in close quarters.
Ah, the joys of schooldays!

John Tillman
Reply to  Mr.
July 27, 2020 11:57 am

Tubby was a climate criminal!

Ben Vorlich
Reply to  Mr.
July 27, 2020 11:59 am

My wife and I often (pre lockdown) got to Pub Quizzes. She a linguist and did several years Latin at school and Uni. It’s surprising how often Latin gives her the answer to a question.

John Tillman
Reply to  Ben Vorlich
July 27, 2020 12:15 pm

A smattering of Latin and Greek helps in technical subjects, too, like science.

Or even ordering food in Romance languages. Many years ago, I asked a buddy with beginning level Spanish if he really wanted turkey wing at a poultry counter in Chile. He asked how I knew the word for “wing”. Same as in Latin, I said. As a former air cavalryman, he should have known that a Roman legion’s horse unit, between a troop and squadron in size (120 riders), was called an “ala”.

Birds’ leading edge slat, their “thumb”, is called an alula, ie “little wing”.

And the way Chileans cook “ala de pavo” is delicious.

Reply to  Ben Vorlich
July 28, 2020 12:24 am

In case of French, you have to pay attention, “aile” is the wing, but “ail” is garlic

John Tillman
Reply to  Ben Vorlich
July 28, 2020 11:18 am

For sure.

But garlic goes great on wings!

“Aile à la ail”.

Lots of things to be careful of in French.

John Tillman
Reply to  Ben Vorlich
July 28, 2020 11:27 am

Less confusing in Spanish: “ala de ajo”.

Soon every word in French will sound like every other word, and they’ll be back to grunts, bird calls and hand signals.

Reply to  Mr.
July 27, 2020 2:45 pm

We had to learn a longer text by heart, no idea anymore what it was, but I never forgot the beginning: “Factum est autem”
It was a complete A4 page of text, if I remember well, it was about a week to learn it completely.

To know some basics is not bad at all, in case of scientific names of plants or animals, as some Greek basics too.

John Tillman
Reply to  Krishna Gans
July 28, 2020 11:23 am

My guess is Luke 2:6 in the Vulgate, Jerome’s translation of the NT.

Factum est autem cum essent ibi impleti sunt dies ut pareret.

While they were there, the time came for the baby to be born, (NIV)

Komerade Cube
Reply to  Mr.
July 27, 2020 8:55 am

Hey, you know how it works – it’s not what you’ve done, but what have you done for me lately?

Pat from kerbob
Reply to  Mr.
July 27, 2020 6:51 pm

Ok, besides roads and transportation, medicine, aqueducts, Sanitation, law and order, etc what have the bloody romans ever done for us??

Right-Handed Shark
July 27, 2020 8:27 am

I don’t doubt that it was warmer during the Roman period than now. But:
I have often wondered how anybody could calculate sea surface temperatures from thousands of years ago. What proxies could there possibly be that can’t be compromised by currents and storms.

“Framed within the study, experts analysed the Mg(Ca relation of samples of foraminifera Flobigerinoides ruber, present in marine sediments, an indicator of sea water temperatures. These unicellular organisms, part of the marine zooplankton, have a specific habitat limited to the surface layers of the water column. “Therefore, the chemical analysis of its carbonated skeleton allows us to reconstruct the evolution of the temperature of the surface water mass over time”, notes Isabel Cacho.”

How can they possibly know that these foraminifera Flobigerinoides ruber had not spent most of their lives in the cooler Atlantic and had only recently been blown in by a storm before they died and sank to the sea floor? And how, pray tell, does a single-cell organism have a skeleton, carbonated or otherwise?

Not picking holes, genuinely curious.

Reply to  Right-Handed Shark
July 27, 2020 9:16 am

They always have a skeleton It’s nothing new.
On the other hand, I think they ment foraminifera Globigerinoides

Reply to  Krishna Gans
July 27, 2020 9:30 am
Right-Handed Shark
Reply to  Krishna Gans
July 27, 2020 2:21 pm

OK, but none of those creatures are “uni-cellular”. Amoebas are uni-cellular, a skeleton of any description must by definition be multi-cellular so any creature with a skeleton cannot be uni-cellular. That’s what was confusing me, a poor description.

Reply to  Right-Handed Shark
July 27, 2020 2:34 pm


Foraminifera (forams for short) are single-celled organisms (protists) with shells or tests (a technical term for internal shells). They are abundant as fossils for the last 540 million years. The shells are commonly divided into chambers that are added during growth, though the simplest forms are open tubes or hollow spheres. Depending on the species, the shell may be made of organic compounds, sand grains or other particles cemented together, or crystalline CaCO3 (calcite or aragonite).

Fully grown individuals range in size from about 100 micrometers to almost 20 centimeters long. Some have a symbiotic relationship with algae, which they “farm” inside their shells. Other species eat foods ranging from dissolved organic molecules, bacteria, diatoms and other single-celled algae, to small animals such as copepods.


Reply to  Right-Handed Shark
July 27, 2020 2:36 pm


Foraminifera (forams for short) are single-celled organisms (protists) with shells or tests (a technical term for internal shells). They are abundant as fossils for the last 540 million years. The shells are commonly divided into chambers that are added during growth, though the simplest forms are open tubes or hollow spheres. Depending on the species, the shell may be made of organic compounds, sand grains or other particles cemented together, or crystalline CaCO3 (calcite or aragonite).

Fully grown individuals range in size from about 100 micrometers to almost 20 centimeters long. Some have a symbiotic relationship with algae, which they “farm” inside their shells. Other species eat foods ranging from dissolved organic molecules, bacteria, diatoms and other single-celled algae, to small animals such as copepods.


Foraminifera (foraminifers or, informally, just forams) are single-celled amoeboid protists.

John Tillman
Reply to  Right-Handed Shark
July 27, 2020 3:16 pm

Lots of unicellular organisms have shells and even mineralized internal parts.

Protists are eukaryotes, large unicells with nuclei and organelles, like animal, fungus and plant cells. Forams are atypical in sometimes having more than one nucleus, making them quasi-multicellular.

John Tillman
Reply to  Right-Handed Shark
July 27, 2020 3:45 pm

PS: “Ameoboid” refers to their shape. They’re not even in the same phylum as true amoebas, which are eukaryotic unicells so large that they’re sometimes visible to the naked eye. They’re famous for their enormous genomes, and are fairly closely related to animals.

The protists closest to animals however are choanoflagellates, which resemble sperm and form colonies. They’re practically identical to choanocytes, the feeding cells of sponges. “Choano” refers to the collars with which both cell types trap bacteria, their food.

Choanoflagellates even make some of the same proteins formerly thought unique to animals, such as the key connective molecule collagen. Amoebas are probably the next closest of our kin, as motile, heterotrophic eukaryotes, just not multicellular.

Reply to  Right-Handed Shark
July 27, 2020 9:28 am

In the study the refer to “based in Mg/Ca ratios measured on the planktonic foraminifer Globigerinoides ruber

The Archaeology News Network…. doesn’t worth the paper maybe printed on

John Tillman
Reply to  Krishna Gans
July 27, 2020 10:12 am

Yup, that’s a pretty funny typo. Must have the same proofreader as the Grauniad used to.

John Tillman
Reply to  Right-Handed Shark
July 27, 2020 10:20 am

They look at layers built up over a long time. And G. ruber is a shallow-water planktonic “foram”, an amoeboid protist with a shell or “test”. So it can’t easily blow in from anywhere distant.

Reconstructing SST by various proxies is a well-validated scientific procedure.

Reply to  John Tillman
July 27, 2020 10:51 am

Seems not to be unusual to find G. ruber in Mediterranean Sea, following the scientific literature, just in the eastern part. (far away from Gibraltar)
only Google

John Tillman
Reply to  Krishna Gans
July 27, 2020 10:58 am

Yup. The Med has different temperatures, so harbors different foram species.

However, their concentration in its different parts at various times can be used to estimate paleotemperatures.

Reply to  John Tillman
July 27, 2020 2:29 pm

Not only different temperatures, but different salinity too.

…Our results suggest that salinity may act as a significant secondary control on Mg/Ca ratios in addition to the dominant temperature control. A re-analysis of previous calibrations from other settings also suggests that salinity changes may contribute to the variations seen in the open ocean. We suggest that caution should be used when using Mg/Ca as a palaeotemperature proxy in areas of high salinity, such as the Caribbean, or where large salinity changes have occurred in the past.

East Mediterranean Sea has a higher salinity as the western part with Atlantic influence.
At least, in the study mentioned in the cited article of the thread, they had a look at salinity.

Right-Handed Shark
Reply to  John Tillman
July 27, 2020 2:39 pm

OK, I can see how it could work in the Med, but in open oceans these creatures live and die in the same narrow column of water? Not buying it. For example, they must be transported thousands of miles by the gulf stream, so they might spend nearly all their life in warm water and die in the North Sea. How can you estimate SST from that scenario?

Again, genuinely curious.

John Tillman
Reply to  John Tillman
July 27, 2020 3:11 pm


Forams can move.

Also, if water conditions, eg temperature and, as Krishna notes, salinity, are no longer conducive to their survival, they die out and are replaced by other species more adapted to prevailing conditions.

Foram reconstructions are checked against a variety of other paleoproxies.

Reply to  John Tillman
July 27, 2020 3:12 pm

In Mediterranean Sea is no Golfstream, never ever.

Bruce Cobb
July 27, 2020 8:41 am

A little-known fact about the decline of the Roman empire is that they threw these wild parties dressed up in costumes made of bedsheets called “togas” and sandals, with sprigs of ivy in their hair, and consumed enormous quantities of beer and engaged in all manner of raucous debauchery and silliness. It was the beginning of the end.
2,000 years later, in colleges, especially “ivy league” ones, toga parties were revived, possibly signaling the decline of said stalwart institutions. One interesting addition to the ritual was to fill the mouth as full as possible with mashed potatoes, and then, using both fists “exploding” the white mass everywhere, possibly mimicking the ancient adolescent ritual of pimple-popping (no one knows).

Jeff Alberts
Reply to  Bruce Cobb
July 28, 2020 7:32 am

I think someone made a documentary about that.

July 27, 2020 9:56 am

Very very unlikely since there was no Ferrari, no Alfa Romeo, no Lamborghini and no Maserati at the time.

Gordon A. Dressler
July 27, 2020 10:18 am

The Roman Warm Period had to have been caused by all the mankind-caused methane emissions from the hundreds of thousands of horses raised to support the Roman legions in their conquests in Europe, the Middle East and North Africa.

Or at least this is what the climate alarmists would like you to believe . . . you see, it’s all about “greenhouse gases”.

John Tillman
Reply to  Gordon A. Dressler
July 27, 2020 10:49 am

Horses are less methanogenic than ruminants, but Romans used oxen, too. Actually, Roman legions didn’t have a great many horses. Mostly, they were marching infantry (4800 to 5000 at full strength), with perhaps 120 cavalry, but they did rely on auxilliary light cavalry (also infantry, bringing a legion up to division-size, ie, about 10,000). The men of course also produced methane, especially given their legume-rich diet.

Lots of trees were cut down to build the Roman and Carthaginian fleets.

Bob boder
Reply to  John Tillman
July 27, 2020 1:51 pm

You are confusing early Roman legions with later periods, Roman legion were very cavalry oriented during the later empire.

John Tillman
Reply to  Bob boder
July 27, 2020 2:52 pm

I’m describing the Roman legion from the Republic to the very end of the Empire, ie about 800 years, ie c. 500 BC to AD 300. The cavalry mix did change from 4200 infantry and 300 cavalry under the Republic to 5200 infantry and 120 auxilia in the Imperial period.

Only in the AD 300s did “legions” become much smaller and cavalry increase, in order to cover more border with fewer troops, and to counter mobile invaders such as Huns and Alans. So just for under 200 years of decline and fall. But formations of around 1000 men weren’t really legions any more.

John Tillman
Reply to  Bob boder
July 27, 2020 2:57 pm

Maybe you had the Byzantine army in mind, which did come to rely more heavily on cavalry over the many centuries of its existence, especially in the 7th to 11th.

Bob boder
July 27, 2020 10:24 am

I find it interesting that we have had a string of articles lately showing the Roman and ME warming periods were warmer than now, the last couple I have read don’t have the expect genuflecting to The global warming masters at the end either. Has the system started to crack a bit?

July 27, 2020 11:45 am

All the power in Rome with problems and then weather. There is almost humor in that.

Ulric Lyons
July 27, 2020 12:53 pm

The Roman Warm Period for West Europe was largely in the first few centuries AD. From around 350 was the start of the Early Antique Little Ice Age on and off through to the late 400’s, the study indicates warmer SST’s then (figure 2). The late Bronze Age collapse peaking 1250-1195 BC during a grand solar minimum is also indicated as having warmer SST’s. That convinces me that they have their earlier NAO reconstruction upside down. Climatologists are experts at rewriting history to make it conform to their back to front theories.

Reply to  Ulric Lyons
July 27, 2020 2:52 pm

Tht’s the study, the article refers to. 😀
So, not so “new”.

July 27, 2020 1:29 pm

But…but…it’s (500 yrs of) “regional warming”

Bill Parsons
July 27, 2020 7:14 pm

From the graph it would appear that the Early Bronze Age Greeks had a climate even more conducive to a cultural efflorescence than the Romans during had during their warm period nearly 2,000 years hence. And they took advantage of it: great temples, beautiful scupture, a warring, competitive culture that strove in the sciences, mathematics, astronomy. Homer… Similarly the modern Aegean warm period, another 2,000 years, and today’s Greeks, who have given us, great, um, re-enactments of Classical Antiquity. And the ocarina.

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