History by proxy

In a study from Proceedings of the National Academy of Sciences, we learn something simultaneously fascinating and alarming; humanity's fingerprint on the globe is so clear that it can even track our wars, famines, and plagues -- back twenty-five centuries or more.

The whole thing was done using proxy records, which involve using indirect sources of evidence about the past to infer what conditions were like.  A commonly-employed one is using the constituents of air bubbles in amber and ice to make inferences about the global average air temperature at the time -- a technique that shows good agreement with the measurements of the same variable using other methods.

Here, in a team effort from the Desert Research Institute, the University of Oxford, the Norwegian Institute for Air Research, the University of Copenhagen, the University of Rochester, and the Alfred Wegener Institute for Polar and Marine Research, researchers studied ice cores from thirteen different locations in the polar northern hemisphere, and found that the levels of one contaminant in the ice -- lead -- was enough to parallel all of the major plagues and wars that occurred in Europe and northern Asia back to 800 B.C.E.

What they found is that lead concentrations in the ice rose when things were quiet and prosperous, probably due to an expansion of smelting operations for items like lead seams for stained-glass windows and impurities in silver ore processing.  If the signature of wars was clear, the signature from plagues was blatantly obvious; the years following the Plague of Justinian (541-542 C.E.) and the two spikes of the Black Death (1349-1352 and 1620-1666 C.E.) were two of the lowest points on the graph.

"Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 C.E.), for example, indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like the German Harz and Erzgebirge Mountains," said study lead author Joseph McConnell of the Desert Research Institute.  "Lead pollution in the ice core records declined during the Late Middle Ages and Early Modern Period (about 1300 and 1680 C.E.) when plague devastated those regions, however, indicating that economic activity stalled."

Silver smelting plant in Katowice, Poland, ca. 1910 [Image is in the Public Domain]

The authors write:

Lead pollution in Arctic ice reflects midlatitude emissions from ancient lead–silver mining and smelting.  The few reported measurements have been extrapolated to infer the performance of ancient economies, including comparisons of economic productivity and growth during the Roman Republican and Imperial periods.  These studies were based on sparse sampling and inaccurate dating, limiting understanding of trends and specific linkages.  Here we show, using a precisely dated record of estimated lead emissions between 1100 B.C.E. and 800 C.E. derived from subannually resolved measurements in Greenland ice and detailed atmospheric transport modeling, that annual European lead emissions closely varied with historical events, including imperial expansion, wars, and major plagues.  Emissions rose coeval with Phoenician expansion, accelerated during expanded Carthaginian and Roman mining primarily in the Iberian Peninsula, and reached a maximum under the Roman Empire.  Emissions fluctuated synchronously with wars and political instability particularly during the Roman Republic, and plunged coincident with two major plagues in the second and third centuries, remaining low for >500 years.  Bullion in silver coinage declined in parallel, reflecting the importance of lead–silver mining in ancient economies.  Our results indicate sustained economic growth during the first two centuries of the Roman Empire, terminated by the second-century Antonine plague.

Of course, there's nowhere in the ice cores that has as high a level of lead contamination as recently-deposited ice does.  "We found an overall 250 to 300-fold increase in Arctic lead pollution from the start of the Middle Ages in 500 C.E. to 1970s," said Nathan Chellman, a doctoral student at the Desert Research Institute, and co-author on the study.  "Since the passage of pollution abatement policies, including the 1970 Clean Air Act in the United States, lead pollution in Arctic ice has declined more than 80 percent.  Still, lead levels are about 60 times higher today than they were at the beginning of the Middle Ages."

As an aside, the Trump administration v. 2.0 has already promised to drastically roll back regulations requiring industry to conform to reasonable pollution standards, including allowable levels of air pollution.  So look for the contaminants in ice -- and in your lungs -- to spiral upward once again.

But hey, if the price of eggs goes down, then fuck the environment, amirite?  

Of course I'm right.  Nothing to worry about.  MAGA FTW!

Ahem.  Back to reality.

As I've pointed out (repeatedly), what we are doing does have a measurable, quantifiable effect on the environment, and studies like McConnell et al. should be a significant wake-up call.  And as I've also pointed out, it probably won't.  It's all too easy for people to say, "Meh, what do I care about a little lead in Arctic ice?  So it bothers a few seals and polar bears.  Too bad for them."  And continue with our throw-away, gas-guzzling, conspicuous-consumption lifestyles.

It's cold comfort knowing that when the aliens come here in a thousand years to find out why the Earth is barren, they'll be able to figure it out by looking at the traces we left behind in the ice, soils, rocks, and air.

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Frozen lightning

Regular readers of Skeptophilia will recognize the name Andrew Butters, my fellow blogger over at the wonderful Potato Chip Math.  Andrew and I are so much alike that mutual friends suspect we were twins separated at birth.  Besides both being bloggers, we are both novelists, were both physics majors (degrees we completed despite the fact that, to put it bluntly, we both kind of sucked at it), both have seriously demented senses of humor, and both love weird and arcane science stuff.

It's this last commonality that has earned Andrew mention in Skeptophilia more than once, because he frequently passes along science news articles he runs across, and a good many of these have ended up here.  And today I once again give him my tip o' the hat for sending me a link to a story from Science about some recent research on the topic of fulgurites.

What's a fulgurite, you might ask?  The -ite ending might clue you in to surmise correctly that we're talking about some sort of mineral.  Fulgurite isn't just some ordinary garden-variety rock, though.  Fulgurites are formed when lightning strikes the ground, discharging into soil that has a high mineral (and low organic matter) content.  When this occurs, an electrical potential difference of as much as a hundred million volts is bridged.

This is what physicists call "a hell of a big short circuit."  Lightning releases all the energy stored in that potential in a fraction of a second.  The column of air through which the current passes superheats, generating the light flash and booming shock wave we associate with a nearby strike.

But it doesn't expend all its stored energy on its passage through the air.  As the current dissipates in the ground, it generates so much heat that it melts the minerals in the soil, when then fuse together into a twisted tube of glass that charts the pattern the lightning bolt took once it struck.

Fulgurites [Image licensed under the Creative Commons John Alan Elson, Fulgsdcrb, CC BY-SA 4.0]

The topic comes up because the article Andrew sent me a couple of days ago is about a geologist, Jonathan Castro, at the Johannes Gutenberg University of Mainz, who came up with the novel idea of using fulgurites to chart ancient climate trends.  Fulgurites are often found near mountaintops -- the peak of Mount Shasta, for example, is pitted with them, the rock blackened and scarred from the hundreds of hits the mountain has taken.  Castro found that when a fulgurite forms, it evaporates all the water in the glass chunk formed; the fulgurite then begins to take up water again at a slow and steady rate, so the water content in the pores of the glass can give you a good idea of when it formed.

Not only does this serve to date lightning strike frequency -- and thus give data about the paleoclimate -- it also can be used to time the advance and retreat of glaciers.  A strike onto a thick layer of ice would cause shock cracks and melting, but in short order there'd be no trace left of it.  Once the glacier retreats and exposes bare rock surfaces, though, any strikes would cause the formation of long-lasting fulgurites.

So, fossilized frozen lightning.

Reading about this sort of thing always makes me realize something I never thought about during the years of my abortive attempt to launch a career in scientific research.  Research depends not only on technical know-how and a solid background in your subject, it depends hugely on creativity -- the capacity for coming up with a way of tackling the question at hand in a novel way.  When I read about Castro's use of fulgurites to date the movement of glaciers, my first thought was, "I never would have thought of doing that."  It's not just that I'm not a geologist -- and actually, because of growing up around my rockhound dad, I knew about fulgurites before reading the article -- I just can't imagine being scientifically creative enough to put fulgurites together with glaciers together with water uptake rates by glass and come up with a new lens on the climate ten-thousand-odd years ago.

But I have the utmost respect for anyone whose brain does work that way.  When Andrew sent me the link, my response was, "Okay, that is just cool."  And it once more points at something I've said many times before; if you're interested in science -- even if you were kind of a washout as a physics student -- you'll never, ever be bored.

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If you, like me, never quite got over the obsession with dinosaurs we had as children, there's a new book you really need to read.

In The Rise and Fall of the Dinosaurs: A New History of a Lost World, author Stephen Brusatte describes in brilliantly vivid language the most current knowledge of these impressive animals who for almost two hundred million years were the dominant life forms on Earth.  The huge, lumbering T. rexes and stegosauruses that we usually think of are only the most obvious members of a group that had more diversity than mammals do today; there were not only terrestrial dinosaurs of pretty much every size and shape, there were aerial ones from the tiny Sordes pilosus (wingspan of only a half a meter) to the impossibly huge Quetzalcoatlus, with a ten-meter wingspan and a mass of two hundred kilograms.  There were aquatic dinosaurs, arboreal dinosaurs, carnivores and herbivores, ones with feathers and scales and something very like hair, ones with teeth as big as your hand and others with no teeth at all.

Brusatte is a rising star in the field of paleontology, and writes with the clear confidence of someone who not only is an expert but has tremendous passion and enthusiasm.  If you're looking for a book for a dinosaur-loving friend -- or maybe you're the dino aficionado -- this one is a must-read.

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

History by proxy

In a new study from Proceedings of the National Academy of Sciences, we learn something simultaneously fascinating and a little alarming; humanity's fingerprint on the globe is so clear that it can even track our wars, famines, and plagues -- back twenty-five centuries or more.

The whole thing was done using proxy records, which involve using indirect sources of evidence about the past to infer what conditions were like.  A commonly-used one is using the constituents of air bubbles in amber and ice to make inferences about the global average air temperature at the time -- a technique that shows good agreement with the measurements of the same variable using other methods.

Here, in a team effort from the Desert Research Institute, the University of Oxford, the Norwegian Institute for Air Research, the University of Copenhagen, the University of Rochester, and the Alfred Wegener Institute for Polar and Marine Research, researchers studied ice cores from thirteen different locations in the polar northern hemisphere, and found that the levels of one contaminant in the ice -- lead -- was enough to parallel all of the major plagues and wars that occurred in Europe and northern Asia back to 800 B.C. E.

What they found is that lead concentrations in the ice rose when things were quiet and prosperous, probably due to an expansion of smelting operations for items like lead seams for stained-glass windows and impurities in silver ore processing.  The signature of wars was clear, but the signature from plagues was blatantly obvious; the years following the Plague of Justinian (541-542 C.E.) and the two spikes of the Black Death (1349-1352 and 1620-1666 C.E.) were two of the lowest points on the graph.

"Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 CE), for example, indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like the German Harz and Erzgebirge Mountains," said study lead author Joseph McConnell of the Desert Research Institute.  "Lead pollution in the ice core records declined during the Late Middle Ages and Early Modern Period (about 1300 and 1680 C.E.) when plague devastated those regions, however, indicating that economic activity stalled."

Silver smelting plant in Katowice, Poland, ca. 1910 [Image is in the Public Domain]

The authors write:

Lead pollution in Arctic ice reflects midlatitude emissions from ancient lead–silver mining and smelting.  The few reported measurements have been extrapolated to infer the performance of ancient economies, including comparisons of economic productivity and growth during the Roman Republican and Imperial periods.  These studies were based on sparse sampling and inaccurate dating, limiting understanding of trends and specific linkages.  Here we show, using a precisely dated record of estimated lead emissions between 1100 BCE and 800 CE derived from subannually resolved measurements in Greenland ice and detailed atmospheric transport modeling, that annual European lead emissions closely varied with historical events, including imperial expansion, wars, and major plagues.  Emissions rose coeval with Phoenician expansion, accelerated during expanded Carthaginian and Roman mining primarily in the Iberian Peninsula, and reached a maximum under the Roman Empire.  Emissions fluctuated synchronously with wars and political instability particularly during the Roman Republic, and plunged coincident with two major plagues in the second and third centuries, remaining low for >500 years.  Bullion in silver coinage declined in parallel, reflecting the importance of lead–silver mining in ancient economies.  Our results indicate sustained economic growth during the first two centuries of the Roman Empire, terminated by the second-century Antonine plague.

Of course, there's nowhere in the ice cores that has as high a level of lead contamination as recently-deposited ice does.  "We found an overall 250 to 300-fold increase in Arctic lead pollution from the start of the Middle Ages in 500 CE to 1970s," said Nathan Chellman, a doctoral student at the Desert Research Institute, and co-author on the study.  "Since the passage of pollution abatement policies, including the 1970 Clean Air Act in the United States, lead pollution in Arctic ice has declined more than 80 percent.  Still, lead levels are about 60 times higher today than they were at the beginning of the Middle Ages."

As an aside, the Trump administration has steadily rolled back regulations requiring industry to conform to reasonable pollution standards, including allowable levels of air pollution.  So look for the contaminants in ice -- and in your lungs -- to spiral upward once again.

But hey, it means the economy's good, so nothing to worry about, right?

Of course right.

So as I've pointed out (repeatedly), what we are doing does have a measurable, quantifiable effect on the environment, and studies like McConnell et al. should be a significant wake-up call.  And as I've also pointed out, it probably won't.  It's all too easy for people to say, "Meh, what do I care about a little lead in Arctic ice?  So it bothers a few seals and polar bears.  Too bad for them."  And continue with our throw-away, gas-guzzling, conspicuous-consumption lifestyles.

It's cold comfort knowing that when the aliens come here in a thousand years to find out why the Earth is barren, they'll be able to figure it out by looking at the traces we left behind in the ice, soils, rocks, and air.

**************************************

This week's Skeptophilia book recommendation is pure fun for anyone who (like me) appreciates both plants and an occasional nice cocktail -- The Drunken Botanist by Amy Stewart.  Most of the things we drink (both alcohol-containing and not) come from plants, and Stewart takes a look at some of the plants that have provided us with bar staples -- from the obvious, like grapes (wine), barley (beer), and agave (tequila), to the obscure, like gentian (angostura bitters) and hyssop (Bénédictine).

It's not a scientific tome, more a bit of light reading for anyone who wants to know more about what they're imbibing.  So learn a little about what's behind the bar -- and along the way, a little history and botany as well.

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

Listening to Cassandra

In Greek mythology, Cassandra was the daughter of King Priam and Queen Hecuba of Troy.  Apollo fell in love (well, fell in lust, actually) with her, and gave her the gift of perfect foreknowledge.  But afterward, Cassandra decided that love affairs with the Greek gods seldom ended well, and told Apollo she wasn't interested.  Apollo was furious, but once a god gives a gift, it can't be revoked, so he just added a clause to it.

She had perfect foreknowledge, but when she told people what was going to happen, no one believed her.  Thus it was that she foresaw the Trojan War and the fact that Troy would be defeated and destroyed -- and instead of taking steps to prevent it, the people of Troy locked her up as a madwoman.

The people who understand climate and ecology are feeling a lot like Cassandra these days.

Now, though, what is being forecast isn't the destruction of a single city, but a trend that is well on its way to triggering a mass extinction.  And we had a study funded by the Smithsonian Institute released last week that highlights the trouble we're in -- a survey of the global climate that extends back five hundred million years.

The temperature data was derived from the ratio of O-16 to O-18 in bubbles of air trapped in ice,  amber, and bound up in calcium carbonate in fossils.  Because water molecules with the lighter isotope evaporate faster and therefore end up in precipitation -- including snowfall -- more readily, air that is enriched in the heavier isotope indicates colder temperature.  This method has been checked against other types of proxy records and shows good agreement, indicating that the technique gives a reliable indication of global average temperature.

If you take a look at the link I posted, you'll see a graph that should be alarming.  The first thing is that we're currently heading toward a frightening benchmark -- a world with no polar ice caps.  The amount of sea level rise this would engender isn't certain, but the current best estimate is about 65 meters, which would be sufficient to inundate every coastal city in the world, not to mention virtually the entire states of Florida, Delaware, and Louisiana and the countries of Belgium, Bangladesh, and the Netherlands.

Scott Wing, one of the scientists who led this research.  During the Paleocene-Eocene Thermal Maximum, there were alligators swimming in what are now the Wyoming Badlands.

The other thing to notice is the slope of the lines on the graph.  On a graph with time on the x-axis, the slope of the graph gives you the rate.  The current rate is one of the three highest on the graph -- and the other two correspond to the two biggest extinction events the Earth has ever experienced, the Ordovician-Silurian Extinction and the Permian-Triassic Extinction.

To quote Paul Voosen, who wrote the article in Science:

Scott Wing and Brian Huber, a paleobotanist and paleontologist, respectively, at the [Smithsonian], wanted to chart swings in Earth's average surface temperature over the past 500 million years or so.  The two researchers also thought a temperature curve could counter climate contrarians' claim that global warming is no concern because Earth was much hotter millions of years ago.  Wing and Huber wanted to show the reality of ancient temperature extremes—and how rapid shifts between them have led to mass extinctions.  Abrupt climate changes, Wing says, "have catastrophic side effects that are really hard to adapt to."

That's putting it mildly.  During the Permian-Triassic Extinction, 95% of the species on Earth died, and the cause was the eruption of the Siberian Traps, which dumped huge amounts of carbon dioxide into the atmosphere, jumping the global average temperature by ten degrees.

So there are two concerns, only one of which people tend to focus on.  There's the actual temperature rise, which is certainly scary enough, but more frightening still is how fast it's happening.  Yes, as climate change deniers will happily tell you, there have been climatic ups and downs throughout Earth's history.  But the one happening now is happening at a rate several orders of magnitude more quickly than anything we have on record.

Of course, this is only the last piece of a mountain of evidence supporting the validity of anthropogenic climate change and the amount of trouble we're in.  Yet still our leaders waffle and cast doubt and talk about expediency and short-term profits and how hard it would be to switch to renewable energy.

And the rest of us keep trying to call attention to the actual science, and are left feeling like Cassandra, knowing that Troy is about to fall but incapable of getting anyone to listen.

The problem is that here, we're not talking about one city's demise, but the long-term habitability of the entire Earth.

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Back in 1989, the United States dodged a serious bullet.

One hundred wild monkeys were imported for experimental purposes, and housed in a laboratory facility in Reston, Virginia, outside of Washington DC.  Soon afterwards, the monkeys started showing some odd and frightening symptoms.  They'd spike a fever, become listless and glassy-eyed, and at the end would "bleed out" -- capillaries would start rupturing all over their body, and they'd bleed from every orifice including the pores of the skin.

Precautions were taken, but at first the researchers weren't overly concerned.  Most viruses have a feature called host specificity, which means that they tend to be infectious only in one species of host.  (This is why you don't need to worry about catching canine distemper, and your dog doesn't need to worry about catching your cold.)

It wasn't until someone realized the parallels with a (then) obscure viral outbreak in 1976 in Zaire (now the Republic of Congo) that the researchers realized things might be much more serious.  To see why, let me just say that the 1976 epidemic, which completely wiped out three villages, occurred on...

... the Ebola River.

Of course, you know that the feared introduction of this deadly virus into the United States didn't happen.  But to find out why -- and to find out just how lucky we were -- you should read Richard Preston's book The Hot Zone.  It's a brilliantly-written book detailing the closest we've come in recent years to a pandemic, and that from a virus that carries with it a 95% mortality rate.  (One comment: the first two chapters of this book require a bit of a strong stomach.  While Preston doesn't go out of his way to be graphic, the horrifying nature of this disease makes some nauseating descriptions inevitable.)

[Note:  If you purchase this book through the image/link below, part of the proceeds will go to supporting Skeptophilia!]