Alaskan volcano linked to mysterious period with extreme climate in ancient Rome

The cold, famine and unrest in ancient Rome and Egypt after the assassination of Julius Caesar in 44 BCE has long been shrouded in mystery. Now, an international team, including researchers from the University of Copenhagen, has found evidence suggesting

UNIVERSITY OF COPENHAGEN

PHYSICS The cold, famine and unrest in ancient Rome and Egypt after the assassination of Julius Caesar in 44 BCE has long been shrouded in mystery. Now, an international team, including researchers from the University of Copenhagen, has found evidence suggesting that the megaeruption of an Alaskan volcano may be to blame.

Dark times befell upon the Mediterranean around the time of Julius Caesar’s assassination in 44 BCE. Written accounts describe the region as severely impacted by unusual cooling, failed harvests, famine and disease, all of which combined to contribute to the fall of the Roman Republic and Ptolemaic Kingdom. While researchers long suspected that a volcanic eruption was to blame, they were unable to pinpoint exactly where and when such an eruption might have occurred.

The brightness of the sun was darkened, the disc was pale for a year and the sun did not rise with its usual brilliance and force. It gave but slight heat. For this reason, the crops brought forth were so poor and immature that they rotted in the cold air.

Greek Roman philosopher Plutarch describing the weather in the wake of Julius Caesar’s death

Now, an international team, including researchers from the University of Copenhagen’s Niels Bohr Institute, the Desert Research Institute in Reno, Nevada and the University of Bern has analysed volcanic ash in Greenlandic ice core samples, which together with historical accounts, can be linked to an inexplicable cooling event in the Mediterranean region during this crux in the history of Western civilization.

The ash comes from the remote Okmok volcano in Alaska’s Aleutian Island Chain. According to the ice core tests, the volcano experienced a two-year megaeruption that began in early 43 BCE, one that filled Earth’s atmosphere with enough smoke and ash to significantly impact climate.

“The eruption is regarded as one of the largest volcanic eruptions of the past 2,500 years. Using the ice core samples, climate models and historical records, we are quite certain that the eruption is linked to the violent climatic changes noted around the Mediterranean and in Rome,” says Jørgen Peder Steffensen, professor of ice, climate and geophysics at the Niels Bohr Institute and one of the researchers behind the discovery.

Coldest years in the Northern Hemisphere

In an extensive collaboration with historians and others, researchers collected prehistoric climate data from around the planet to confirm the likelihood that this particular eruption was responsible for widespread climate change. The sources of evidence include tree ring archives from Scandinavia, Austria and California and a Chinese cave formation.

The researchers’ extensive analysis of climate during this ancient era demonstrates that the years after the Okmok eruption were some of the coldest in the northern hemisphere over the past 2,500 years. The researchers’ climate models indicate that temperatures were roughly seven degrees Celsius below normal during the summer and autumn after the eruption in 43 BCE.

“Historical accounts describe how wet and extremely cold weather led to poorer harvests, as well as how the Nile overflowed its banks–destroying crops and leading to famine–all of which correlates with our results,” says Jørgen Peder Steffensen.

While the researchers believe that a variety of factors contributed to the fall of the Roman Republic and Ptolemaic Kingdom, they maintain that Okmak’s eruption played an unmistakably large role and that their discovery serves to fill in gaps which have been missing in history books dealing with the era.

The research was recently published in the journal Proceedings of the National Academy of Sciences (PNAS)

Facts:

The Niels Bohr Institute’s Ice and Climate Group has been working on the “Caesar Volcano” since the 1980’s. The group was the first in the world to systematically use the counting of annual layers in ice cores to date volcanic eruptions.

The group also invented the ECM-method (Electric Conductivity Method) to find volcanic ash in ice cores. ECM consists of placing two electrodes along fresh ice cores and measuring resistance. Sulphuric acid from volcanoes changes the resistance in the ice, making it quite easy to identify volcanic layers.

The new research article is the latest in more than 40 years of work on the volcano.

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From EurekAlert!

49 thoughts on “Alaskan volcano linked to mysterious period with extreme climate in ancient Rome

  1. You mean it wasn’t all that methane spewing livestock that caused the poor air quality?

    • But isn’t the Okmok eruption Trump’s fault, anyway?
      I’m sure that was what the BBC wrote!

      Auto –
      Mods – /Sarc. Obviously [surely it’s obvious!].

  2. Darn . . . that’s climate change not being caused by human emissions. Oh, the tragedy of it all!

  3. Thank goodness such volcanic-driven climate events, along with natural climate variability, are a thing of the past. It’s all anthropogenic CO2 driven now.
    Read it in the IPCC reports, written by climate experts, I did.

    • Would not the precautionary principle guide us to increase CO2 emissions and temperatures, if possible, in order to avoid the worst negative impacts of the inevitable next colossal volcanic eruption?

      • The precautionary principle will lead you to attempt all sorts of irrational actions.

      • I don’t see why not … except that if we (as a society) were to implement such a policy; then we (as a government) would not not be able to admit to the concept of diminishing returns; and we (as a people) would be subject to ever expanding inefficient/ridiculous administrative efforts to increase the temperature through increasing the atmospheric CO2.

        HEY, if we (the sheeple) really want to decrease atmospheric temperature we should put the U.N. in charge of INCREASING atmospheric temperature. A big budget, that increases in proportion with the programs’ enormous needs, would guarantee that current temperatures would remain static & past temperatures would rise.

  4. So, some more documentation of what happens when the earth cools, so now, all in favor of cooling the earth raise your hands? Only a few crazy skiers? Greta? AlGore? Sign me “freezing my patootie in Argentina and waiting for that global warming deal to kick in.

  5. The real story is the weather, not climate, cooled. Life became a struggle, the citizen people were miserable, therefore it was blamed on a politician.

  6. What about glaciers in the Alps? What other data sets did not make the cut?

    How often does the Nile overflow its banks?

    • ResourceGuy
      These days the Nile is highly controlled because since the completion of the Aswan Dam irrigation has extended the crop growing area of Egypt to places that were arid desert.
      Before that Nile floods were a good thing because they not only watered the land but also deposited silt. Is it being seriously suggested that the eruption altered seasonal Nile flows? Low Nile flows were the real problem, famine and disorder certainly followed that.

      But with Ethiopia on the verge of completing a new massive dam which will allow it to build up a huge hydro-electric power reservoir, things could get very nasty because Egypt is very unhappy about possible loss of control of the Nile’s flow northwards of Ethiopia.
      Considerably more dangerous a situation than some never actually appearing CO2 fantasy.

  7. By some climate reconstructions, 44 BCE falls near the middle of a warm interval on Earth generally know as the “Roman Warm Period”. By other paleoclimatology dating, 44 BCE falls near the end of the Roman Warm Period. The above article invites the question: was this mega-eruption in Alaska the root cause of the end of the Roman Warm Period?

    BTW, to those that may argue the Roman Warm Period was not a global event, there is a summary of data at http://www.co2science.org/subject/r/summaries/rwpeurope.php that cites research papers showing that higher-than-average warmth existed at this time in Iceland, Ireland, northwest continental Europe (including today’s countries of Sweden, Spain and Germany).

    And JoNova steps up with a this summary statement: “A quick tour of peer reviewed research around the globe shows it was also warmer in China, North America, Venezuela, South Africa, and the Sargasso Sea 2000 years ago. And of course, Greenland tells an evocative tale.” (see: http://joannenova.com.au/2010/05/gullible-rudd-steps-right-in-it/ )

  8. I read an article once that tied this event to grand solar minimum. And stated that more volcanoes and and earthquakes occur during solar minimum. Seems to be the case now actually. Colder weather and volcanic ash in the atmosphere is double whammy.
    But at least we can laugh at the man made climate change idiots at Weather Underground.

    • Only the silica rich magma volcanoes erupt more during a solar minimum… which correlates to the explosive kind. Almost all the really big ones went off during a minimum in the past couple of millennia. You can do a web search and there are quite a few papers on this. The theory makes a lot of sense.

      It’s really too bad we don’t put more resources into planning for either a mega blast or coronal mass ejections that will devastate the grid. These happen infrequently, but it only takes one to wreck our civilization and in a really big way. CME’s are especially nasty. The paper that just came out forecasting solar cycle 25 to be an all time big one would really jeopardize us if it materializes.

      • I would be surprised if anyone has a rational, scientific basis for predicting CMEs over the course of a full 11-year (+/-) solar cycle. Astronomers have not been observing CME for all that long a time.

        A positive correlation of the frequency of CMEs with sunspot number has been established (ref: https://geoscienceletters.springeropen.com/articles/10.1186/s40562-016-0039-2 ), but to the best of my knowledge nobody has developed a model or other means of predicting when one might be imminent. The fact that we are presently in a “quiet Sun” period–one likely to continue for at least the next five or more years (well into solar cycle 25)–argues against the chances of a really large CME (say that associated with an X-class solar flare) occurring anytime soon.

        A Web search reveals that the last really big CME was is July 2012 (https://science.nasa.gov/science-news/science-at-nasa/2014/23jul_superstorm ). It did not impact Earth, but instead hit the STEREO-A spacecraft.

        In terms of a giant CME wrecking our civilization, if Earth is unfortunately directly struck by one, there are no measures we can take to prevent this from happening.

    • So it wasn’t due to power hungry politicians after all ? But my history teacher said…..

  9. If just Caesar had put satellites in orbit, he would have known who or what to blame for Climate Change.

    • Alternatively, if there was just an IPCC* back then, it would have told Caesar what and who to blame.

      “Off with their heads”, of course.

      *That would be Imperial Panel on Climate Change, chartered to find reasons that subjects of the empire cause climate change.

    • But, first the Romans would have to recognize that the Earth was spherical. Not clear the they did, although the ancient Greeks seem to have noticed this.

      • Romans knew Earth is spherical, although Pliny the Elder did conjecture that it might not be perfectly so, but rather pine cone-shaped. In fact, it’s a lumpy spheroid. He died trying to save victims of the AD 79 eruption of Vesuvius.

        However Romans adopted the Aristotelian model, as perfected by 2nd century AD Roman citizen Claudius Ptolemy, of Alexandria, Egypt, whose system held sway until Copernicus, Kepler and Galileo. All educated Romans read Greek.

  10. Why the floods and rain? If it was colder wouldn’t that slowdown/stop the evaporation / rain cycle?

  11. So the massive release of particulates and CO2 resulted in cooling. I’d hate to have to reconcile that cognitive dissonance. I’m sure it’s because “higher injection”, and a host of other things they can’t model.

  12. Everyone interested in climate, plagues, their relationship to the Roman Empire’s collapse and it’s relationship to what we see today should read recently published “The Fate of Rome” by Kyle Harper via the Princeton Press in 2017.

    https://www.amazon.com/Fate-Rome-Climate-Disease-Empire/dp/0691192065/ref=sr_1_1?crid=32BZK4JW7KGUB&dchild=1&keywords=the+fate+of+rome+kyle+harper&qid=1594659255&sprefix=The+Fate+of+Rome%2Caps%2C811&sr=8-1

    It covers how their advanced development of densely populated city-states, road linked trade routes, water and canal systems on the one hand, and complete ignorance of any medical or germ theory at a time of climate change created the perfect storm for plagues to sweep their world on a mass scale for the first time in history.

    The book is great reading, and thoroughly researched with nearly 100 pages of references, charts and appendixes. It’s relevance to all the discussions we have today with climate change and Covid-19 can’t be missed.

  13. Well, I’ll accept the loss of heat from volcanic particles in the upper atmosphere blocking the Sun, but was that a continuous two year eruption, or a single mega-eruption event, followed by a long period of smaller eruptions? And can we expect that again any time soon?

    Just askin’, because Mt. Erebus in Antarctica sits on a rift line and constantly erupts, and as you may or may not know (sarc), Antarctica is kind of cold and awash in snow and ice. 🙂

    Another question, because Fuji-san has been quivering lately, and hasn’t erupted since 12/16/1707: what’s the likelihood of Fuji-san erupting and what could we climate deniers** expect if it did erupt?

    And last but not least, what kind of effect might it have on bird migrations, if the sun is blocked from their view? They seem to time their takeoffs by whether or not they can see the sun, because that’s their main navigation guide.

    As long as it does not interfere with my popcorn supply, and does not make my furnace run all year ’round, I”m good with it. **I’m thinking about having some tee shirts printed with an erupting volcano and a flying goose flock above the blazon “climate denier’.

    Good article, thanks for posting that.

  14. Plutarch’s Life of Caesar acknowledges climate impact after Julius Caesar’s assassination, but attributes it to divine forces:

    Among events of man’s ordering, the most amazing was that which befell Cassius; for after his defeat at Philippi he slew himself with that very dagger which he had used against Caesar; and among events of divine ordering, there was the great comet, which showed itself in great splendour for seven nights after Caesar’s murder, and then disappeared; also, the obscuration of the sun’s rays. For during all that year its orb rose pale and without radiance, while the heat that came down from it was slight and ineffectual, so that the air in its circulation was dark and heavy owing to the feebleness of the warmth that penetrated it, and the fruits, imperfect and half ripe, withered away and shrivelled up on account of the coldness of the atmosphere.

    • Exactly. Caesar was a god. No need to look for further explanations. Being a god he was understandably pissed off at having been killed by mere humans. That’s why he did his climate trick.

      According to proxies the climate turned sour starting around 1750 BP and worsened until ~1500 BP. That’s 200-450 AD. So the Roman Warm Period did not end before 200 AD, and what happened around J.C.’s death was just a cold snap. I guess this people did not get to read my report. Climate has an effect on volcanoes. Volcanoes have no effect on climate:
      https://wattsupwiththat.com/2018/05/10/the-effect-of-volcanoes-on- climate-and-climate-on-volcanoes/

  15. I would assume the drop-in temperature is only for the Northern Hemisphere.

    From the article.

    …”The ash comes from the remote Okmok volcano in Alaska’s Aleutian Island Chain.”

    A near, instant, drop in temperature of 7 degrees Celsius in the summer and autumn temperatures, is difficult, to even imagine.

    The fact that Northern Hemisphere temperature quickly recovered from a 7C step forcing change, is proof planet resists temperature changes (by increasing or decreasing planetary cloud cover, particularly in the equatorial region) rather than amplifies temperature changes (positive feedback).

    A drop in the Northern Hemisphere of 7 degrees Celsius, during the summer and autumn would result in crop failures in Canada, Russia, Northern Europe, China, and Northern US.

    From the article quantifying the estimate change.

    The researchers’ extensive analysis of climate during this ancient era demonstrates that the years after the Okmok eruption were some of the coldest in the northern hemisphere over the past 2,500 years.
    The researchers’ climate models indicate that temperatures were roughly seven degrees Celsius below normal during the summer and autumn after the eruption in 43 BCE.

  16. Does anyone know if this eruption is recorded in glacial ice or seafloor sediment? You would think an eruption that severe would leave some kind of marker.

  17. [oops, Name got mangled, try again]
    Plutarch’s Life of Caesar acknowledges climate impact after Julius Caesar’s assassination, but attributes it to divine forces:

    Among events of man’s ordering, the most amazing was that which befell Cassius; for after his defeat at Philippi he slew himself with that very dagger which he had used against Caesar; and among events of divine ordering, there was the great comet, which showed itself in great splendour for seven nights after Caesar’s murder, and then disappeared; also, the obscuration of the sun’s rays. For during all that year its orb rose pale and without radiance, while the heat that came down from it was slight and ineffectual, so that the air in its circulation was dark and heavy owing to the feebleness of the warmth that penetrated it, and the fruits, imperfect and half ripe, withered away and shrivelled up on account of the coldness of the atmosphere.

  18. If only the ancient Romans had worn masks! I heard masks protect everyone from invisible and distant dangers.
    /snark

  19. Uh-oh, my comment went into moderation for using the k word. Jeez.

    OK, this people (scientists?) got it all wrong. The Roman Warm Period ended ~200 AD according to multiple climate proxies, and climate worsened until ~450 AD triggering the migration period. The Roman Republic fell for socio-political reasons not climate ones. And climate has an effect on volcanoes, but volcanoes don’t have an effect on climate.
    https://wattsupwiththat.com/2018/05/10/the-effect-of-volcanoes-on- climate-and-climate-on-volcanoes/

  20. Seems we just recently discussed the Okmok Roman era eruption.

    The researchers were able to identify Okmok ash in one ice core, but failed to find it in another ice core…

    Meanwhile, Steve McIntyre published an Antarctic ice core analysis at Climate Audit.

    Not surprisingly, that ice core does not indicate anything unusual in the weather. Though, the resolution will not capture extremely brief natural fluctuations.

    The researchers above have a very tenuous almost correlation they’re desperately trying to promote with their personal opinions and conclusions.

  21. See what happens when you assassinate Julius Caesar?

    There’s a lesson there.

    Don’t do it again.

  22. I wish the article had covered how they IDed the specific volcano. None of the commentors asked this question. Likewise MOST people don’t question the death of Epstein not the fall of building 7 (in its own footprint and partially at freefall speed). Office fires? Not a chance.

    • The ID process is in the paper, but it requires a subscription.

      https://www.pnas.org/content/117/27/15443

      About 100 million people doubt that Epstein killed himself.

      Old WTC 7 didn’t free fall, but collapsed progressively, as the columns supporting its awkward structure gave way. Its construction was strange in order to accommodate the ConEd substation over which it was built.

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