The worst century in history

I've always loved a mystery, and for that reason, the European "Dark Ages" have fascinated me for as long as I can recall.

But the moniker itself is off-puttingly self-congratulatory, isn't it?  It's not like Roman rule was that pleasant for your average slob to live under, after all.  Be that as it may, after the conquests of the Roman Empire started to fall apart in the fourth century C.E. from a combination of invasion, misrule, and downright lunacy, things went seriously downhill.  Life was pretty rough until the eighth and ninth centuries, when some measure of order returned as damn near all of Europe coalesced around the Roman Catholic Church, ushering in the Middle Ages.  And what we know about the period in between is... not a hell of a lot.  Accounts are scattered, vague, and full of conflation with mythology and legend.  The few that were written by contemporaries, rather than long after the fact -- such as Gregory of Tours's History of the Franks -- contain as much hagiography as they do history.

St. Gregory and King Chilperic I, from Grandes Chroniques de France de Charles V (fourteenth century) [Image is in the Public Domain]

Which is why I was thrilled to read a paper that appeared in Antiquity about a study of the "worst decade to be alive" -- 536-546 C. E.

The research, which combines the skimpy evidence we have from accounts written at the time with hard scientific data from analysis of ice cores, paints a grim picture.  Writings from the year 536 describe a mysterious "fog" that lasted for eighteen months, generating widespread crop failure and what one Irish cleric called "three years without bread."  From the ice core analysis, medieval historian Michael McCormick and glaciologist Paul Mayewski identified what they believe to be the culprit: a cataclysmic volcanic eruption in Iceland that dropped the global temperature an average of two degrees Celsius in a matter of months.

This was followed by another eruption in 540, and the following year, the single worst plague on record -- the so-called "Plague of Justinian," which killed between a third and a half of the inhabitants of the Eastern Roman Empire, and resulted in so many corpses that people loaded them on ships and dumped them in the Mediterranean.  The disease responsible isn't known for certain, but is believed to be Yersinia pestis -- the same bacterium that caused the Black Death, almost exactly eight hundred years later.  But to give you an idea of the scale, there's reason to believe the Plague of Justinian dwarfed both the fourteenth century Black Death and the Spanish Flu of 1918-1919 -- usually the two examples that come to mind when people think of devastating pandemics.  The death toll is estimated at sixty million.

There probably was a connection between the cold and the plague, too, although not the obvious one that famine triggers disease susceptibility.  Many scholars think that the lack of food, and cold temperatures following a period that had generally been warm, forced mice and rats into homes and on board ships -- not only in close proximity to humans, but in their means of travel.  The fleas they carried, which are vectors for the plague, went with them, and the disease decimated Europe and beyond.

The effects of the eruption, however, were felt all over the Earth.  Tree ring analysis from North America shows 540 and the years following to have been unusually cold, with short-to-nonexistent growing seasons.  Volcanic dust is found in those layers of ice cores everywhere they exist.  Famines occurred in Asia and Central America.

All in all, a crappy time to be around.

Things didn't rebound for almost a hundred years.  Archaeologist Christopher Loveluck, of the University of Nottingham, found traces of dust containing significant amounts of lead in ice strata from the year 640, which he believes were due to a resurgence in silver smelting for coinage.  (I suppose if there's a hundred years during which your three main occupations are (1) not starving, (2) not freezing, and (3) not dying of a horrible disease, then making silver coins is kind of not on your radar.)  And the tree rings and ice cores bear out his contention that this indicates better conditions; although there were a couple of other volcanic eruptions we can see in the glacial records, none were as big as the one in 536.  The silver smelting, Loveluck says, "... shows the rise of the merchant class for the first time."  Things, finally, were improving.

What's coolest about this study -- despite its gruesome subject -- is how hard science is being brought to bear on understanding of history.  We no longer have to throw our hands up in despair if we're interested in a time period from which there were few written records.  The Earth has recorded its own history in the trees and the glaciers, there for us to read -- in this case, telling us the tale of the worst century the human race has ever lived through.

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The house of cards

I was first introduced to the idea that human history has been shaped by climate swings back in 1990, with British science historian James Burke's prescient two-part documentary After the Warming.  In part one, he tracks the (natural) ups and downs that have occurred because of gradual shifts in the Earth's orbit and rotational axis; in part two, he then looks at the effects humans are having because of our out-of-control burning of fossil fuels and use-it-once-then-throw-it-away culture of consumerism.  From my standpoint now, thirty-two years after the documentary was released, his predictions seem nothing short of uncanny, right down to the United States's steadfast determination not to do a damn thing to address anthropogenic climate change.  But he even got a lot of the more specific effects spot-on.  For example, he predicted the crazy spate of Atlantic storms that caused billions of dollars of damage and resulted in the NOAA running out of hurricane names and having to switch over to "Alpha," "Beta," and "Gamma," even getting it right down to the year it occurred (2005).  Watching it now, it's almost like it was made today by someone with a slight penchant for bending the truth, not by someone three decades ago for whom all of these were merely shrewd forecasts.

If I have one criticism of Burke, it's that he gives the impression that everything in history boils down to the climate.  Part one, entertaining and enlightening as it is, is kind of a ninety-minute long exploration of the single-cause fallacy.  That said, it's still a sobering cautionary tale.  We can't discount the effects that shifts in the climate can have on humanity.  Right now in the central and southern United States we're trapped in a heat wave that has already broken records in an area that's accustomed to summer heat; simultaneously the much-more-poorly-prepared people of western Europe are not only facing record high temperatures but droughts and wildfires.

It remains to be seen how long it'll take before the climate naysayers will finally, grudgingly, admit that we've been right all along.

Another of Burke's oversights is an interesting one; although he considers other natural phenomena, he doesn't look at the effects of volcanic eruptions on the climate.  It may be because these are drastic, but usually short-lived; long-time readers of Skeptophilia may recall a piece I wrote a while back on the effects of an eruption in Iceland in the sixth century C. E. that was the principal cause of "the worst decade in history" -- a series of plagues, famines, and catastrophically cold winters that killed an estimated sixty million people.  It took nearly a hundred years for the effects to abate, and when they did, they led into an unusually warm period (probably because of the injection of carbon dioxide into the atmosphere by the eruption).  An even bigger eruption, this one in Indonesia about seventy-four thousand years ago, is thought by some scientists to have nearly caused the human species to go extinct -- the "Toba Bottleneck" may have reduced the entire human population of the Earth to under ten thousand individuals.  (This conclusion, however, is still under serious debate amongst scientists.)

The reason all this comes up is because of an article at the site Yale Climate Connections sent to me by a loyal reader, which describes the historical impact of an eruption I'd never heard about -- the eruption of the Alaskan volcano Mount Okmok in 43 B. C. E.  

The caldera of Mount Okmok [Image courtesy of photographer Christina Neal and the USGS]

It was another massive one, with global effects.  Tree ring analysis from the White Mountains of California give evidence of the second-coldest winter on record.  Written accounts from Rome describe cold, dry summers that caused agricultural failures several years running; in Egypt, it manifested as the loss of the annual floods of the Nile River three times in a row, resulting in devastating drought and famine.

This, in turn, contributed to the collapse of the Ptolemaic Empire in Egypt, then ruled by the famous and charismatic Queen Cleopatra VII.  

It's a little alarming to see how quickly the climate can change, and the havoc such changes can wreak.  It's why people like me have been sounding the alarm for decades, urging caution instead of what we've been doing, which is blundering about as if everything around us is permanent, as if we're guaranteed a clement climate and plenty of food and water.  All you have to do is to look at history to realize how precarious things are.  While I won't go as far as James Burke did in attributing damn near everything to the climate, there's no denying that in many ways the interlocking systems of our planet have the fragility of a house of cards.  Some things -- such as volcanic eruptions and orbital shifts -- we can't do anything about.  But once you see the effects of climate change on the history and habitability of the Earth, I don't see how you wouldn't come away absolutely convinced that we better do everything we can to protect the part of it we can do something about.

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Descent into chaos

There's an interesting concept called sensitive dependence on initial conditions.

Here's a simple example.  If you take a deep bowl, and drop a marble into it, it doesn't take any great intelligence or insight to predict what the end state will be.  Marble on the bottom of the bowl.  It doesn't matter how high you drop it from or where exactly it hits the sides first.  After a bit of rolling around, the marble will stop moving at the bottom.

Now, do the same thing -- but with the bowl flipped over.  Where will the marble end up?

Impossible to say, because it is an inherently chaotic system.  You could do it a hundred times and the marble will end up in a different place each time, because its final location depends on exactly the speed and angle of its path, where it hits the curved edge of the bowl, even whether the marble is spinning a little or not.  A system like this is said to be "sensitive to initial conditions" -- therefore unpredictable.  Perturb it a little by altering it in a tiny way, and you get a completely different outcome.

Here's a much cooler example, that I stumbled across in doing research for this post.  It's called a double compound pendulum.  Take two rigid rods, and suspend one so it's free to swing.  Then tie the second rod to the bottom of the first.  Start with the rods pulled horizontal, then let it go.  Can you predict how the whole system will move?

Simple answer: no.  It's a chaotic system.

[GIF is in the Public Domain]

A little mesmerizing to watch, isn't it?

The reason this comes up is because there's decent evidence that the intersection between the Earth's climate and human society is a chaotic system that has at least some degree of sensitive dependence to initial conditions.  If you perturb it, it may not respond the way you expect -- and sometimes small changes in one location can lead to big ones somewhere else.  (This concept was made famous as "the butterfly effect.")

As an example of this, take the research that was released just last week in Proceedings of the National Academy of Sciences, the link to which was sent to me by a friend and loyal reader of Skeptophilia yesterday.  In "Extreme Climate After Massive Eruption of Alaska’s Okmok Volcano in 43 BCE and Effects on the Late Roman Republic and Ptolemaic Kingdom," by a team led by Joseph R. McConnell of the University of Cambridge, we find out about an Alaskan volcanic eruption that may have been one of the significant factors leading to the collapse of the Roman Republic, and its consolidation as an empire -- events that radically changed the course of history in Europe and North Africa.

Geologists on the team identified tephra (volcanic ash) in ice cores from the Arctic that were fingerprinted chemically and shown to come from the volcano named Okmok in the Aleutian Islands.  The dating of the tephra deposit shows that the eruption happened in 43 B.C.E. -- right after the assassination of Julius Caesar, during a time when Rome was in chaos as various political factions were duking it out for control.  The eruption of this volcano halfway around the world is also correlated with the coldest year Europe had for centuries, possibly longer.  Snow fell in summer, crops failed, there were famines and repeated uprisings by desperate and starving citizens.

This sudden drop in temperature was one of the factors that contributed to the realignment of the Roman government as someone emerged who said he knew what to do to fix the situation -- Octavian (later known as Augustus), Julius Caesar's great-nephew.  And he did it, establishing the Pax Romana, quelling the revolts and ushering in two centuries of relative peace and prosperity for Roman citizens (and wreaking havoc on the Gauls, Celts, Teutons, and whatever other tribes happened to be in the way of the Roman Legions).

It helped, of course, that once the volcanic tephra from Okmok settled out, the temperature rebounded, and the first years of Augustus's reign were noted for a beneficent climate and rich crop yields.  Not all of the good bits of the Pax Romana were due to Augustus's skill as an emperor; he got lucky because of conditions he had no control over and could not have predicted, just as the last leaders of the Republic got unlucky for the same reasons.

The point here is that we should be wary of perturbing chaotic systems, which is exactly what we're doing by our rampant dumping of carbon dioxide into the atmosphere.  And what we're seeing over the last decades is exactly the sort of unpredictable response -- some areas experiencing droughts, others floods; deadly heat waves and trapped polar vortexes that drop areas into the deep freeze for weeks; increased hurricanes, tornadoes, and bomb cyclones.  One of the frustrations felt by the people who understand climate systems is that the average layperson doesn't see this kind of  unpredictability as precisely what you'd expect from pushing on an inherently chaotic system.  If you can't make predictions to pinpoint accuracy -- "okay, because the climate is changing, you can expect it to be 95 F in Omaha on July 19" -- it's nothing to be concerned about.

"The scientists don't even know what's going on," you'll hear them say.  "Why should we believe it's a problem if they can't tell us what the outcome is going to be?"

But that's exactly why we shouldn't be messing with it.  Systems that have sensitive dependence to initial conditions are dramatically unpredictable, and get pushed out of equilibrium quickly and sometimes with catastrophic results.

As the leaders in the final years of the Roman Republic found out.

I feel like another figure from the Classical world -- Cassandra -- for even bringing this up.  Cassandra, you may recall, is the woman who was cursed by the gods to having accurate foresight and knowledge of the future, but with the difficulty that whatever she says, no one believes.  The climatologists have been sounding the alarm about this for decades, to little effect.  If you can't accurately predict the outcome, to most politicians, it doesn't exist.

Which makes me wonder if before we try to get our leaders to get on board with addressing anthropogenic climate change, we should require they sit through some lectures on chaos theory.

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I know I sometimes wax rhapsodic about books that really are the province only of true science geeks like myself, and fling around phrases like "a must-read" perhaps a little more liberally than I should.  But this week's Skeptophilia book recommendation of the week is really a must-read.

No, I mean it this time.

Kathryn Schulz's book Being Wrong: Adventures in the Margin of Error is something that everyone should read, because it points out the remarkable frailty of the human mind.  As wonderful as it is, we all (as Schulz puts it) "walk around in a comfortable little bubble of feeling like we're absolutely right about everything."  We accept that we're fallible, in a theoretical sense; yeah, we all make mistakes, blah blah blah.  But right now, right here, try to think of one think you might conceivably be wrong about.

Not as easy as it sounds.

She shocks the reader pretty much from the first chapter.  "What does it feel like to be wrong?" she asks.  Most of us would answer that it can be humiliating, horrifying, frightening, funny, revelatory, infuriating.  But she points out that these are actually answers to a different question: "what does it feel like to find out you're wrong?"

Actually, she tells us, being wrong doesn't feel like anything.  It feels exactly like being right.

Reading Schulz's book makes the reader profoundly aware of our own fallibility -- but it is far from a pessimistic book.  Error, Schulz says, is the window to discovery and the source of creativity.  It is only when we deny our capacity for error that the trouble starts -- when someone in power decides that (s)he is infallible.

Then we have big, big problems.

So right now, get this book.  I promise I won't say the same thing next week about some arcane tome describing the feeding habits of sea slugs.  You need to read Being Wrong.

Everyone does.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

The worst century in history

I've always loved a mystery, and for that reason, the European "Dark Ages" have fascinated me for as long as I can recall.

But the moniker itself is off-puttingly self-congratulatory, isn't it?  It's not like Roman rule was that pleasant for your average slob to live under, after all.  Be that as it may, after the conquests of the Roman Empire started to fall apart in the 4th century C.E. from a combination of invasion, misrule, and downright lunacy, things went seriously downhill.  Life was pretty rough until the 8th and 9th centuries, when some measure of order returned as damn near all of Europe coalesced around the Roman Catholic Church, ushering in the Middle Ages.  And what we know about the period in between is... not a hell of a lot.  Accounts are scattered, vague, and full of conflation with mythology and legend.  The few that were written by contemporaries, rather than long after the fact -- such as Gregory of Tours's History of the Franks -- contain as much hagiography as they do history.

St. Gregory and King Chilperic I, from Grandes Chroniques de France de Charles V (14th century) [Image is in the Public Domain]

Which is why I was thrilled to read a paper that appeared last week in Antiquity about a study of the "worst decade to be alive" -- 536-546 C. E.

The research, which combines the skimpy evidence we have from accounts written at the time with hard scientific data from analysis of ice cores, paints a grim picture.  Writings from the year 536 describe a mysterious "fog" that lasted for eighteen months, generating widespread crop failure and what one Irish cleric called "three years without bread."  From the ice core analysis, medieval historian Michael McCormick and glaciologist Paul Mayewski identified what they believe to be the culprit: a cataclysmic volcanic eruption in Iceland that dropped the global temperature an average of two degrees Celsius in a matter of months.

This was followed by another eruption in 540, and the following year, the single worst plague on record -- the so-called "Plague of Justinian," which killed between a third and a half of the inhabitants of the Eastern Roman Empire, and resulted in so many corpses that people loaded them on ships and dumped them in the Mediterranean.  The disease responsible isn't known for certain, but is believed to be Yersinia pestis -- the same bacterium that caused the Black Death, almost exactly eight hundred years later.  But to give you an idea of the scale, there's reason to believe the Plague of Justinian dwarfed both the 14th century Black Death and the Spanish Flu of 1918-1919 -- usually the two examples that come to mind when people think of devastating pandemics.  The death toll is estimated at sixty million.

There probably was a connection between the cold and the plague, too, although not the obvious one that famine triggers disease susceptibility.  Many scholars think that the lack of food, and cold temperatures following a period that had generally been warm, forced mice and rats into homes and on board ships -- not only in close proximity to humans, but in their means of travel.  The fleas they carried, which are vectors for the plague, went with them, and the disease decimated Europe and beyond.

The effects of the eruption, however, were felt all over the Earth.  Tree ring analysis from North America shows 540 and the years following to have been unusually cold, with short-to-nonexistent growing seasons.  Volcanic dust is found in those layers of ice cores everywhere they exist.  Famines occurred in Asia and Central America.

All in all, a crappy time to be around.

Things didn't rebound for almost a hundred years.  Archaeologist Christopher Loveluck, of the University of Nottingham, found traces of dust containing significant amounts of lead in ice strata from the year 640, which he believes were due to a resurgence in silver smelting for coinage.  (I suppose if there's a hundred years during which your three main occupations are (1) not starving, (2) not freezing, and (3) not dying of a horrible disease, then making silver coins is kind of not on your radar.)  And the tree rings and ice cores bear out his contention that this indicates better conditions; although there were a couple of other volcanic eruptions we can see in the glacial records, none were as big as the one in 536.  The silver smelting, Loveluck says, "... shows the rise of the merchant class for the first time."  Things, finally, were improving.

What's coolest about this study -- despite its gruesome subject -- is how hard science is being brought to bear on understanding of history.  We no longer have to throw our hands up in despair if we're interested in a time period from which there were few written records.  The Earth has recorded its own history in the trees and the glaciers, there for us to read -- in this case, telling us the tale of the worst century the human race has ever lived through.

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This week's Skeptophilia book recommendation is a fun one -- Mary Roach's Spook.  Roach is combines humor with serious scientific investigation, and has looked into such subjects as sex (Bonk), death (Stiff), war (Grunt), and food (Gulp).  (She's also fond of hilarious one-word titles.)

In Spook, Roach looks at claims of the afterlife, and her investigation takes her from a reincarnation research facility in India to a University of Virginia study on near-death experiences to a British school for mediums.  Along the way she considers the evidence for and against -- and her ponderings make for absolutely delightful reading.

Apocalypse not

Can I explain something, for what I devoutly hope is the last time?

The Yellowstone Supervolcano is not about to erupt.

This claim has been going around for some time, in various guises.  Once it was because a tourist saw some bison acting oddly and from that jumped to "all the wildlife are leaving the park" and from there to "so it's about to blow sky-high."

Well, this was four years ago, and if the Supervolcano had erupted, I think we would have noticed.  So it's a big "nope" on that one.  Bison may be cool animals, but as geologists, they suck.

Then it got picked up by the conspiracy theorists, who conjectured that NASA or DARPA or FEMA or some other evil government acronym had found out that eruption was imminent, and was conspiring to cover it up so as not to cause mass panic, except some people with websites who really ought to be sedated found out, and were letting us know so we could get the hell out.  All of which was well-meant, I suppose, but it became a moot point when the eruption once again failed to materialize.

[Image licensed under the Creative Commons Clément Bardot, Grand Prismatic Spring, CC BY-SA 3.0]

The latest iteration, which I have now seen posted as a serious claim at least a half-dozen times on social media, is that (1) Yellowstone is going to erupt, and (2) there's a secret NASA program to drill into it and bleed off the heat so they can prevent it.  At least NASA gets cast as one of the good guys, here; I'm sure the scientists are sick unto death of being portrayed as rubbing their hands together and cackling while plotting to destroy the world.

This comes from the apocalyptic site Breaking Israel News, and includes stuff like the following:

After initially denying that the unusual amount of seismic activity witnessed last year was an indication of imminent danger, NASA scientists are proposing a solution that could save half the world while admitting that their intervention could initiate the explosion it was intended to prevent. 

Last year, increased seismic activity at Yellowstone generated a great deal of concern.  More than 2,300 tremors were recorded between June and September, one of the largest earthquake swarms ever recorded at the site.  Though geologists assured the public that the activity was normal for the site, another series of quakes and unusual eruptions beginning in February, increased fears that the supervolcano was waking up.  An investigation revealed magma filling up in the underneath chamber of the supervolcano.  In July, a massive, 100 ft.-wide fissure opened up in the Grand Teton National Park near Yellowstone, further increasing fears. 

To look only at the most egregious errors in that passage:

1. The solution to "save half the world" was proposed in a theoretical sense only by Brian Wilcox of NASA/JPL.  It involves pumping water down a drill shaft into the rock surrounding the volcano, then pumping the resulting steam back to the surface (and using it for electricity production).  This would "bleed off" the heat from the volcano, which would freeze and no longer be a threat.  The problem with this is twofold: first, it would cost 3.46 billion dollars, and second, the bleed-off of heat would be so slow (and the volcano is so large) that it would take hundreds, possibly thousands, of years to cool it enough to stop an eruption.  Which Wilcox says, right there in his paper.
2. The 2,300 tremors between June and September are completely ordinary.  The Yellowstone area gets shaken multiple times on a daily basis, and most of them are too small to feel.  It's a seismically active area.  Recall what "seismically active" means.
3. The fissure in the Grand Tetons had zilch to do with the Supervolcano.  It happened because mountains have landslides sometimes.  Saying it indicates an imminent volcanic eruption is no more sensible than connecting eruptions to bisons acting weird.

So you don't need to cancel your vacation plans to Wyoming yet.  Scientists assure us that there will be plenty of warning if the volcano shows signs of an eruption.

Anyhow, the woo-woos need to give this one a rest, because we're all safe, from that threat, at least.  You'd think the more imminent threat would be climate change and the fact that Trump and his followers seem to be trying to create Nazi Germany 2.0.  Compared to that, I'll accept the risk of Yellowstone erupting without a second thought.

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This week's Skeptophilia book recommendation is something everyone should read.  Jonathan Haidt is an ethicist who has been studying the connections between morality and politics for twenty-five years, and whose contribution to our understanding of our own motives is second to none.  In The Righteous Mind: Why Good People are Divided by Politics, he looks at what motivates liberals and conservatives -- and how good, moral people can look at the same issues and come to opposite conclusions.

His extraordinarily deft touch for asking us to reconsider our own ethical foundations, without either being overtly partisan or accepting truly immoral stances and behaviors, is a needed breath of fresh air in these fractious times.  He is somehow able to walk that line of evaluating our own behavior clearly and dispassionately, and holding a mirror up to some of our most deep-seated drives.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]