More evidence that it's COLD not WARMTH that hurts humanity

From the UNIVERSITY OF HELSINKI and the “after the Roman Warm Period” department

Unusual climate during Roman times plunged Eurasia into hunger and disease

A recent study published in an esteemed academic journal indicates that volcanic eruptions in the mid 500s resulted in an unusually gloomy and cold period. A joint research project of the Chronology Laboratory of the Finnish Museum of Natural History and Natural Resources Institute Finland (Luke) suggests that the years 536 and 541-544 CE were very difficult for many people.

An extended period of little light may make it difficult for humans to survive. The level of production of plants is dependent on the amount of available sunlight. Food production, i.e, farming and animal husbandry, rely on the same solar energy. Humans, meanwhile, become more prone to disease if they are not exposed to enough sunlight to produce vitamin D.

“Our research shows that the climate anomaly, which covered all of the northern hemisphere, was the compound result of several volcanic eruptions,” says Markku Oinonen, director of the Chronology Laboratory.

The aerosols that were released into the atmosphere with the eruptions covered the sun for a long time.

The exceptionally poor climate conditions were significantly detrimental to farming and reduced the production of vitamin D among the populace. This means that the people who were already weakened by hunger also had to grapple with a compromised immune system.

Trees are a re­cord of the past

The study is based on dendrochronology or tree-ring dating. The series of annual growth rings from subfossil – or intact – tree deposits covers the past 7,600 years. The trees are often found on the bottom of small lakes, and Luke has been taking samples and recording the findings since the 1990s.

“Researchers have put together an annual growth ring calendar of treeline pine spanning more than 7,600 years. Various historical events can be contrasted with the calendar. The growth ring calendar is an important indicator of global climate change,” says researcher Samuli Helama from Luke.

The samples in the recent study were dated with the help of the growth ring calendar at Luke, and sample shavings were carved out of them for each calendar year. The Chronology Laboratory then conducted isotope analyses on the samples.

Car­bon iso­topes in­dic­ate sum­mer weather

The results of the study are based on the analysis of the variation of carbon isotopes in the annual growth rings of trees. The variety in carbon isotopes reflects the photosynthesis of the trees, which in turn is largely dependent on the amount of solar radiation available during the summer.

The new study tracks the correlation of carbon isotope variation and volcanic eruptions from the 19th century until recent years, and shows the dramatic reduction in available sunlight in 536 as well as between 541 and 544 CE. The variation of summer temperatures was similarly reconstructed on the basis of the density of the trees’ annual growth rings.

Hard times brought the plague

The unusually poor years coincide with the bubonic plague epidemic that devastated the Roman Empire. The epidemic caused by the Yersinia pestis bacterium began in 542 CE and killed approximately half, or more, of the inhabitants of what was then considered the Eastern Roman Empire. The plague spread through Europe, from the Mediterranean, possibly as far north as Finland, and had killed tens of millions of people by the 8th century.

The study was conducted as a consortium project by the University of Helsinki and Luke, with participation from researchers of the University of Eastern Finland, the Finnish Meteorological Institute, the Geological Survey of Finland and the University of Turku. The research was funded by the Academy of Finland.

###

The study was published in the international series Scientific Reports and is OPEN ACCESS.

Helama S, Arppe L, Uusitalo J, Holopainen J, Mäkelä H M, Mäkinen H, Mielikäinen K, Nöjd P, Sutinen R, Taavitsainen J-P, Timonen M and Oinonen M 2018. Volcanic dust veils from sixth century tree-ring isotopes linked to reduced irradiance, primary production and human health. Scientific Reports 8, http://www.nature.com/articles/s41598-018-19760-w

Abstract

The large volcanic eruptions of AD 536 and 540 led to climate cooling and contributed to hardships of Late Antiquity societies throughout Eurasia, and triggered a major environmental event in the historical Roman Empire. Our set of stable carbon isotope records from subfossil tree rings demonstrates a strong negative excursion in AD 536 and 541–544. Modern data from these sites show that carbon isotope variations are driven by solar radiation. A model based on sixth century isotopes reconstruct an irradiance anomaly for AD 536 and 541–544 of nearly three standard deviations below the mean value based on modern data. This anomaly can be explained by a volcanic dust veil reducing solar radiation and thus primary production threatening food security over a multitude of years. We offer a hypothesis that persistently low irradiance contributed to remarkably simultaneous outbreaks of famine and Justinianic plague in the eastern Roman Empire with adverse effects on crop production and photosynthesis of the vitamin D in human skin and thus, collectively, human health. Our results provide a hitherto unstudied proxy for exploring the mechanisms of ‘volcanic summers’ to demonstrate the post-eruption deficiencies in sunlight and to explain the human consequences during such calamity years.

Palaeoclimate reconstructions. Tree-ring δ13C based reconstruction of irradiance (global radiation) (red line) with Monte Carlo68 based estimates of 95% (orange area) and 99% confidence (yellow area) intervals showing the reduction in irradiance in AD 536 and 541–546 (a). Negative first difference of the reconstructed irradiance recording the change in irradiance from previous to concurrent year (c). European and northern Fennoscandian summer (June–August) temperature reconstructions relative to the AD 1961–1990 baseline

More in the paper, here: http://www.nature.com/articles/s41598-018-19760-w


 

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NW sage

Really interesting. I wonder just how precise carbon dating (measuring the isotope ratios) is these days. When I read about the technique many years ago the precision claimed – based on the sensitivity limits of the instruments not being able to detect very very small amounts of radiation of very specific wavelengths – it was difficult to be very certain of dates to within several years, even centuries. Very hard to pin down a date like 541 AD.

Fritz

Much better now that they count and weigh individual atoms with a mass spec.

Randy Bork

I don’t think they used carbon dating here to get the age of the trees. They used carbon isotope ratios as a proxy for solar flux.

commieBob

They didn’t rely on carbon dating.

Cross-dating of our tree-ring series against the existing mean chronology57 enables the dating of each ring to the exact calendar years.

The paper isn’t that hard or long. Most folks should be able to glean the gist of what they did.

Tom O

True, but the problem as always is supposition is treated as fact. No one can be certain that there weren’t other possible processes that could actually affect isotope ratios. It is always “assumed” that what works today surely was the same “then,” whenever “then” was.
Yes, you have to make those assumptions in order to have some way of trying to determine the past, but you also have to keep in mind that it is not fact you are dealing with, and state it that way. Today, too much of “science” believes its own infallibility.

MarkW

That’s why they put error bars on any date estimate.
The 541AD date was arrived at by counting tree rings.

Crispin in Waterloo but really in Potchefstroom

Date of trees that young is done by counting ring width overlaps. The date is probably spot on.
Interestingly, the Empire that at the time included modern Mongolia was Turkic, and collapsed about this same time (540).
There are Turkish Graves near Ulaanbaatar dated to 535-536. One has a line of standing stones more than twenty kilometers long leading to it.

Michael Kelly

It was actually Thursday, August 5th, 541 AD. At 2:37, Eastern Daylight Time.

Tom Halla

Interesting contribution on plagues, and climate change.

commieBob

In his book, The Fourth Horseman, Andrew Nikiforuk points out that when the population is somehow weakened then plague will follow. Widespread malnutrition does the job nicely. People don’t actually have to starve to death. For instance, in the Irish Potato Famine it is believed that more people died of disease than by starvation. A marginal existence will weaken them sufficiently to permit disease to do its work.

waterside4

Yes indeed Commiebob, typhus together with the 1840’s ‘beast from the east’ caused as many deaths as the potatoes blight in my homeland.
See “The great Hunger” by Cecil (female) Woodham – Smith. A poignant read.

More evidence that it’s COLD not WARMTH that hurts humanity
In other news, the sun will rise tomorrow morning.

Pop Piasa

Who needs more evidence of the obvious? I still think that if the biblical writers had ever experienced -20F they would have described hell differently.

Harrowsceptic

Yes it is the “desert” Religions that describe Hell as a fiery place. Nordic religions tend to have Hell as a cold, dark dismal place.

Crispin in Waterloo but really in Potchefstroom

Hell was early on, 2000 years ago, was a public dump where garbage was burned, including the bodies of the destitute etc. Later, 400 years ago, modern versions of Hell with fire and demons was created by the pen, not the Word.
It happens that in the reformation’s version of Hell the higher/upper layers were hot but at the very bottom, the ninth level down, it was exceedingly cold.
This is from a history course available at one time at the University of Alberta titled, “The history of heaven and Hell.”
Hell through the ages changed a lot. There was no ‘place’ called Hell until quite recently.

Patrick

1. Considering clothing and housing options, a biblical writer experiencing -20 F would require a miracle to live to write about it. Even so, between frostbite and actual roasting, cold isn’t so bad.
2. Crispin, all the notes from that course are best used to line the birdcages of Jehovah’s witnesses. While the Gospel reference to Gehenna referred to an actual dump filled with any number of unclean and awful things, this was not the only biblical mentioning of hell; phrases such as “furnace of fire” and “pool of fire” exist in the NT books. I should also note that the Gehenna valley was once a notorious site of Molech worship, involving the immolation of infants. Also, the Inferno portion of Dante’s Divine Comedy was written between 1308 and 1320. The layers of Hell described are of poetic meaning, but yes, the 9th level is formed from the frozen tears of Satan.

John

Roasting? We are already in the midst and probably end of the current warm period. It isn’t even the warmest period in this interglacial that everyone is flapping their ears over. When cold arrives again, crops will stop producing. That is probably all you have to remember.

Patrick

John – I don’t consider 90°F or so roasting, even in WI, USA. As WI is still dealing with snow and ice right now, we are actively looking for Al Gore’s hiding place.
I was instead observing that pain induced by second degree burns or worse to be greater than frostbite, having suffered both.

Scott Manhart

This is great but it’s confirmatory rather than revolutionary. Historians of the period have known this for quite some time. Still it’s great to get more physical confirmation

So. There are two things we now know about the Dark Ages. They were ages ago, and… they were actually dark. Who’d have thought it?

joelobryan

So do they posit where these sunlight blocking volcano(s) were located? Not Aetna or Pompey.

Tom Billings

“So do they posit where these sunlight blocking volcano(s) were located? Not Aetna or Pompey.”
There are candidate Plinian Eruptions of volcanoes, as widely dispersed as Rabaul, North of Papua, and one of the many in Central America, and even Krakatoa, which all erupted about this time. Major historical sources also reported the effects, from the Spring and Autmn annals in the provinces of China, to the secretary of the Roman General Belisaurius, writing in the newly re-conquered town of Carthage in North Africa that “The Sun, for months, has given no more light than the Moon normally would, and the air is yellowed, …”

2hotel9

I wonder how much effect under-sea volcanoes had in that period? Many times major eruptions in Pacific region volcanoes are accompanied by under-sea eruptions, not to mention they often erupt all on their own! That would be a lot of gas and heat outflow not accompanied by dust, would it not? Lots of vaporized water, too.

John

People don’t seem to understand that virtually all human knowledge, all human inventions, all recorded history has happened in the current 12,000 year period of global warming. It has been stupendous. Each time it cools even a little bit, humans suffer. Guess what? This interglacial is due to stop. 12,000 years ago, there was a mile of ice where NY City now sits. Seas were 500 feet lower. You could walk to Russia.
People don’t understand geological history, and that history repeats. THAT is what is in our future. Some humans will ride that roller coaster into hell. I sincerely hope I’m gone by then. I can only imagine the misery of mass migrations toward the equator, lack of food capacity, and probably at least 80% of the population dying during the process. And people whine about supposed ‘global warming’, when we are on the TOP of a global warming period that is going to eventually disappear…Good grief…people need some perspective. I can’t believe that ‘real’ scientists actually fall for this ‘global warming’ fiction.

interzonkomizar

@John- Guess what? This interglacial is due to stop.
You’re right. It has already. Break out the mukluks an snowshoes.
I sent the following message to several public forums and a senator to see if anybody is interested. If anybody wants the 18 links to articles i used, ask in comments.
NOAA, NASA, and the IPCC have failed humanity, and we’re all in for a nasty surprise … Abrupt Climate Change. This is a summary and warning i put together:
The MsM and warmist alarmists are wrong. It is the heighth of hubris and arrogance to think humans, in the space of 150 years, can change thermal cycles that are thousands of years long and have existed for millenia. The thermal mass of the land and oceans is enormous. The temperature of deep, still, parts of the ocean have barely risen one degree in 22,000 years, the last glacial max.
My reading of the climate tea leaves says we’re already past the interglacial plateau of relatively stable climate.
For the last three thousand years, Since 1000 BC, the end of the Minoan Warm Period, the global temperature trend has been -0.5 to -0.7 dgC per 1000 yrs, projecting full glacial of 8 dgC in another 7,000 yrs. Another clue, the obliquity dropped below 23.5 degrees around 1300 AD, the onset of the Wolf Minimum. Now the glacial cold lurking in the deep ocean, held in check by obliquity for 10,000 years, has been set free, ending the Holocene Interglacial. We are in the transition zone to glacial cold, expect Finoscandian ice sheets to start in 2000 yrs.
However, the solar output has been declining since 1986 and this accelerated in 2009 with solar cycle 24, the lowest in over 100 yrs. Cycle 25 will also be low and the beginning of a Grand Solar Minimum, now named the Eddy Minimum. Expect a Little Ice Age lasting 40 yrs, with some winters extremely cold, some wet cool springs to kill crops, some cold summers, and more frequent and severe storms. The storminess index went from 6.5 to 14 during the LIA. This slide into cold is showing up in German weather station records where the last 30 yrs of winter (DJF) are trending -19 dgC per 1000 yrs, much faster than the slow decline to normal glacials. Zugspitze Mtn. Resort, elev 2000m, january temperature has been trending down 1 dgC per 10 yrs.
I expect in the next ten years one billion will actually starve due to crop failures, and one billion will be eaten by stronger omnivores; feral dogs, cats, and … humans.
As the legal beagles like to say, ‘Time is of the essence,’ so the sooner you act, the better your chances of survival.
Sandy, Minister of Future

Kristi Silber

You got all that out of tea leaves? What kind of tea?

zazove

According to the data, nearly all extreme summer cooling events in the northern hemisphere in the past 2,500 years can be traced to volcanoes.
https://www.smithsonianmag.com/science-nature/sixth-century-misery-tied-not-one-two-volcanic-eruptions-180955858/
Now we can add extreme summer warming events to our calender too.

Pop Piasa

Too bad we can’t schedule warming or cooling events, just as we have no control of temperature beyond fighting UHI microcosmic effects. You’ll have to clear that extreme summer warming with the MJO and ENSO before you schedule it, also.

F. Leghorn

Tell the warming to hurry the hell up. I am so tired of being cold.

Just Jenn

You and me both. I’ve got 14″ of snow coming, 8″ fell last night.
I’m sick of the cold (and I can hear you all now….well then move South!) LOL.
I want to know 1 thing and only 1–who in the world decided that warm was bad? Cuz I’d like to bury that person in the 12″ of snow outside on my patio right now.
On the upswing, I get to test out my new fireplace! And at least it’s bright outside–windy, freezing, driving snow/sleet/ice, but it’s nice and bright all the same and I don’t have anywhere to be. Gotta love Spring Blizzards right?
Maybe not. 😀

Joel O’Bryan – I remember a book titled “Catastrophe” published at least 20 years ago that posited, based on very sketchy historical accounts, a massive volcanic eruption leading to widespread famine and plague. From memory, the eruption year was given as 535. In the historical record, such as it was, were accounts of deserted waste land, and the utter collapse of, for example, a long-lived society in what is now central Yemen (an irrigation-based society based on water storage. The prolonged reduction in sun/light/warmth interrupted the rains which then killed off all the existing tree cover. When the rains eventually returned, after a considerable time, the land was sluiced down to the rock and silt filled the dams. No more c.50,000 population center).
Anyway, the author’s pick for the location of the eruption was a half submerged caldera in Indonesia. So, there’s a candidate.

TimTheToolMan

Reducing the amount of sunlight the earth receives could well end in disaster for us all. Unfortunately because people are so passionate about the dangers of “warming” they think geo engineering solutions can only help because they’re so damned sure that warming is bad for the earth.

Sheri

I wonder if those who have been hit by 4 or more major blizzards and several minor ones (especially the east coast USA and parts of Europe and Russia), with more April snow on the way, might be starting to just maybe question a tiny bit whether or not the predicted warming could be in error.

Pop Piasa

Hey, you should know the routine by now, if it’s a warm winter with an early spring it’s gotta be due to climate change. If it’s frigid and snowy until May, it’s the unprecedented extremes predicted by the climate models.
Keep practicing on the PC circular thinking and soon you’ll understand why the world warming catastrophically is making you so cold.

Sheri

Can’t do it. My head would explode.

Auto

Sheri
Thanks!
Many guffaws!
No monitor casualty this time, though still much appreciated.
Auto

Kristi Silber

I’m one of those. Expecting 8-12 over the next couple days. But more unusual is that the winter snow hasn’t fully melted and the ground is frozen.
I’m also one of those who realize that “global warming” does not affect all parts of the globe the same way, and that we should expect more climatic instability rather than average change. The models predict regional differences. The weakening of the polar vortex was hardly surprising. It’s only when one simplifies climate or doesn’t know about the various ways it’s changing that one thinks a cold winter is evidence that AGW is not happening.

Russ R.

So..changing is now returning to the way it was before we had this latest warm cycle? Or is this “special changing” unlike anything in the past?
I think if you have access to weather records for your location your going to find several mid-April storms similar to the one you are experiencing. The difficulty becomes tying anthropogenic activity to this one and those. Maybe you could go with “more severe”. That seems to be the go to phrase, when the others are getting slammed with evidence.

Bruce Ploetz

“The Fate of Rome” by Kyle Harper makes a similar point about the fall of Rome being caused by climate and the plague. Cold, not warmth.
https://www.amazon.com/Fate-Rome-Climate-Disease-Princeton/dp/0691166838/ref=tmm_hrd_swatch_0?_encoding=UTF8&qid=&sr=

peanut gallery

One thing the Finns know better than most, is the cold.
Still would like to know where the 535/536 volcano is located…

Paul Blase
peanut gallery

Krakatoa doesn’t fit. No geological evidence. The hyped 535 eruption requires a skewing of an old kings list by 100 or so years. Until a tephra horizon is found that correlates, that dog don’t hunt.

…the 19th century until recent years???
The new study tracks the correlation of carbon isotope variation and volcanic eruptions from the 19th century until recent years, and shows the dramatic reduction in available sunlight in 536 as well as between 541 and 544 CE.
I don’t think 536 – 522 was in the 19th century. Maybe the sixth century.

Moderately Cross of East Anglia

Krakatau is recorded in the chronicles of the Javanese as having erupted in ancient times although off the top of my head I can’t remember the exact date, but seems about the suggested date.
Krakatau will undoubtedly do a repeat performance some time in the future as it has already built a new active cone of several hundred feet. At present there are millions of people living in the near vicinity of the stratovolcano and were it to erupt today in the same way as in the 1883 event the consequences would be appalling.

peanut gallery

No physical evidence of krakatoa 535.

Yes, some very poor writing there.
What they undoubtedly mean is that they took the isotope ratios from ~1800 to today, along with the volcanic record (that is the period where we truly had worldwide information about when, where, and how big eruptions were), and correlated the two. Then used that to correlate to temperature, crop failures, etc.
They then used that correlation to calibrate the isotope ratios from the earlier years, extrapolating those to conditions during that disastrous period in late Roman times.
However – there is one other thing that affected the spread of famine and disease in that critical period. Emperor Justinian’s ill-advised war to reconquer the Western Empire accelerated the decline of agriculture in the Mediterranean regions, and aided in the spread of the plague from the Eastern Empire. The catastrophic events would have still occurred, in my opinion – but would they have been quite so bad, and so far-reaching?

dodgy geezer

…The study is based on dendrochronology or tree-ring dating. The series of annual growth rings from subfossil – or intact – tree deposits covers the past 7,600 years. The trees are often found on the bottom of small lakes, and Luke has been taking samples and recording the findings since the 1990s….
Ah… but if we read the proxies UPSIDE DOWN, we see that there was dangerous heating during the Roman Cold Period…..

Auto

And if read upside-down, and [croooocially] in a mirror, we see that Watermelon-Pseudo-Scientists should fund our retirements.
Nice work if I can get it to happen.
Auto

BillP

The study shows that lack of sunlight kills, not cold.
Granted, all other things being equal, less sunlight results in cooling. But but it is the lack of sun, not the cold that kills; an example of “correlation does not equal causality.”
What if other things are not equal? Clouds produced by a warmer surface block sun just as well as volcanic dust.

Geoff Sherrington

BillP,
Taking your thoughts further, there has been discussion about cloud extent being a ‘thermoregulator’ of Earth temperatures. When the volcanic darkening happens, what do clouds do? Do they decrease in area and time persistence to try to allow more sunlight in? Surely the are a test of the regulator hypothesis. There should be preserved proxies, because rather less cloud should lead to rather less rain and snow. But, rather than starting to look back at these years 541-4, maybe more recent large volcanic events are better. Of course, this might all have been done without any papers having crossed my desk, if so, apologies. Geoff.

Volcanic aerosols increase cloud cover (actually, that is the main part of the “darkening” – the aerosols actually don’t block all that much, but the increased condensation in the upper atmosphere does). As these aerosols “wash out,” net cloud cover decreases naturally, allowing more solar energy to reach the surface.

peanut gallery

SO2 injection to the stratosphere takes about 2 mo to become aerosol. In 48 to 50 mo that aerosol returns to pre-emption levels. “Junge Layer”

Kristi Silber

“The study shows that lack of sunlight kills, not cold.”
Exactly. Strange title for the post. A cold period could naturally exacerbate the effects of disease and poor nutrition, at least at high latitudes and altitudes, but volcanoes are not a thing of the past.
This page has a nice summary of the effects of eruptions on the atmosphere.
https://scied.ucar.edu/shortcontent/how-volcanoes-influence-climate
Excerpt:
“The gases and dust particles thrown into the atmosphere during volcanic eruptions have influences on climate. Most of the particles spewed from volcanoes cool the planet by shading incoming solar radiation. The cooling effect can last for months to years depending on the characteristics of the eruption. Volcanoes have also caused global warming over millions of years during times in Earth’s history when extreme amounts of volcanism occurred, releasing greenhouse gases into the atmosphere.”
There is also “an overview of materials that make their way from volcanic eruptions into the atmosphere: particles of dust and ash, sulfur dioxide, and greenhouse gases like water vapor and carbon dioxide.”

Tjipke IJsbrand Winkel

The same happened after the most violent eruption in the history of man of the volcano on the island Sumbawa in Indonesia in 1815.

Peta of Newark

So you have a train.
It’s designed for 60mph and to carry 500 people.
Fine.
Then one day, a $10 wheel bearing shatters – at 60mph fully loaded.
Maybe there’s a graunching noise, some sparks, a small fire but it might come to a stop still on the rails.
OK. A bit inconvenient maybe but no real harm done.
So we go for efficiency efficiency efficiency, speed speed and capacity.
That is The Modern Way after all.
We put 5000 people on the train and run it at 120mph.
Is that train not now in a quadruple whammy situation when the wheel bearing fails?
(half em-ve squared says) it has a much greater chance of jumping the track and taking all 5000 passengers with it.
So it was in 541 CE or whenever.
The Romans had trashed the farmland, orchards and gardens all around the Med. To get food, folks had to move north to where the fertile soil remained. Strictly of course, was put there by ice sheets and glaciers maybe 10,000 years previously. To places of shall we say ‘Variable Climate’
The people pushed things (and themselves) to the peak, the limit, of their contemporary efficiency.
Then something small and trivial happened
The bearing broke. That’s what they do. (I have experience of this. On farm machinery, not trains)
A volcano went off. That’s what they do.
And is it The Human Condition?
We all know that things tend to break, they ‘go wrong’ at always THE most inconvenient time – just when you need whatever system/thing/climate/weather to be behaving at its best.
We keep telling ourselves how clever and intelligent we are but 9 out of 10 stories on here tell exactly the opposite. And how many folks came into this story that it was ‘climate change’ that killed the Romans and are going away even more convinced of same?
The Romans in their heyday installed the faulty wheel bearing. In the shape of a vast bloated bureaucracy surrounded be legions of fawning grasping cronies.
The volcano was simply the tiny pebble lying on the track that caused it to break

Fredar

If we weren’t clever and intelligent we wouldn’t be having this conversation here. We would still be starving in caves with primitive technology. And you would be complaining how modern way is all non-efficiency and stagnation. I wouldn’t call a volcanic eruption “something small and trivial”. And you forget the “tiny” detail that Eastern Roman Empire was also suffering from plague and war from all sides, which would push any society to its limits. But to their credit, Roman empire of the 6th century didn’t fall. It survived another 1000 years. Partly it’s because Eastern Romans adapted while their Western counterparts didn’t. If Romans had modern technology and, you know, less people trying to kill them, they would have fared even better.

Fredar

And also I thought that part of the reason why germanic tribes were migrating south was climate change, which was trashing their lands, so they had to move south to more fertile lands.

JRF in Pensacola

Quite a broad range of Irradiance in the chart? 120-240 watts per sq. meter?

2hotel9

Once again a study of human history shows cold is the enemy, not warmth!
And Anthony? Have I recently thanked you and several other of your posters here for directing me to A Cultural History of Climate and Times of Feast, Times of Famine? Thank you, yet again. Most excellent books and I am oh, so glad WUWT pointed me to them.

beng135

Duh. Even indoctrinated school children could figure this out (but might be afraid to admit it).

Edwin

While I haven’t checked recently I don’t remember the Bubonic Plague happening in the Roman Era though indeed by 542 CE the Empire was in steep decline. Lot’s of diseases impacted the Roman Empire my guess if there was a epidemic it was influenza. Which most people today grossly underestimate. Few know that the Spanish Flu killed more people in recorded history than any other plague; more than died in combat during “The Great War” (aka WWI). And a reduction in vitamin D would have caused problems with the population’s immune systems.

D. J. Hawkins

Look up the plague of Justinian. Oh heck, here you go:
https://en.wikipedia.org/wiki/Plague_of_Justinian

Don Easterbrook

As I (and others) have pointed out here many times, volcanic eruptions are not capable of causing sustained climate change because their effect does not exceed about two years and there is no evidence of unusually high volcanic activity over prolonged periods..

johchi7

Don Easterbrook
It would depend on the volcanic activity in question, to how long an effect would last. Obviously the super volcanoes like those of Yellowstone, Tobac, Siberian Traps and the Deccan Traps had greater impacts than a few years. Just as that of meteors of good size causing similar cooling events – some of which occurred about the same time as the volcanic activities. What makes such occurrences worse; is when they occur during solar minimums when our atmosphere is already compromised, with radiation from other solar systems, that breakdown our atmosphere causing more high cloud cover that blocks out most of our sunlight. It is never just a single thing that causes prolonged cooling, but a combination of two or more occurences.

Michael Ozanne

Isn’t this in the category of well known for years… In the UK The Workplace (Health, Safety and Welfare) Regulations 1992, which supercede the shops and offices acts from the 1930’s establish the minimum working temperatures for sedentary and physical work… hypothermia sneaks up on people and kills them quietly. There is no upper temperature for the likes of smelters or foundries before your clothing spontaneously combusts.. dehydration and hyperthermia take a lot more effort to die from and give a lot more warning…

TomRude

One can always like those climate papers blaming volcanic eruptions dust for all kinds of things yet unable to direct the reader to a deposit of ashes that would provide timing as well as extent of the eruption. Models of course are supposed to be trusted instead.
I am not saying it was not the case, but when implicating a geological event, geological proofs are needed.

Joel Snider

‘Humanity’ is the LAST priority among greenies.
Take seriously their calls for 90% human population reduction.
Remember, ALL the things people said they ‘didn’t really mean’, or ‘they never would’, pretty much have turned out to be ‘yes, they do’, and ‘yes they will… the very second they can.’

Human industrial effluent was blamed for “global cooling” first before it was damned for “global warming.” The modern term “climate change” is a catch-all meant to blame anthropogenic CO2 no matter what the climate chooses to do.

Joel Snider

Something that could not be done without an accomplice press.
This is where the real ‘follow the money’ leads you.

More evidence that Global Warming, is actually a Global Pattern?

swuk

It is surely the full solar spectrum radiation we and Nature need for life and not just the heat it also brings.