A Jurassic wake-up call

About 183 million years ago -- during the Toarcian Age, one of the subdivisions of the early Jurassic Period -- there was a sudden and puzzling extinction.

Things had been recovering nicely after the End-Triassic Mass Extinction, eighteen million years earlier.  While dinosaurs were not yet at the peak they would hit in the later Jurassic, they were well on their way to taking over the place.  The temperatures were cool -- there's evidence of widespread glaciation during the ten million years prior -- but by and large, everything seemed to be coping just fine.

Then, suddenly, wipeout.

It wasn't as big as some of the truly dramatic mass extinctions the Earth has experienced, but that doesn't mean it was insignificant.  Marine invertebrates got clobbered, dropping both in diversity and in overall numbers.  Over ninety percent of coral species went extinct.  Two entire orders of brachiopods died; bivalves, ostracods, and ammonoids survived, but with greatly reduced populations.  Coelophysid and dilophosaurid dinosaurs got wiped out completely.  Seed ferns and lycophytes declined sharply, to be replaced by cycads and conifers.

Fossil seed fern [Image is in the Public Domain]

All of it occurred rapidly -- the current estimates are less than five hundred thousand years, which is a snap of the fingers geologically.

So what happened?

The culprit seems to have been the Karoo-Ferrar Large Igneous Province, an enormous volcanic formation (estimated at about three million square kilometers) now underlying much of southern Africa, eastern Antarctica, and southwestern South America.  At this point, Gondwana -- the southern half of the supercontinent of Pangaea -- had just begun to break up, and this massive series of eruptions was part of the process of rifting.  But what caused the extinction was not the eruption itself -- it was the sudden spike of atmospheric carbon dioxide, which swung the climate from a glacial period to a hothouse.  A study released last week by a team at Duke University found evidence of a twenty thousand gigaton carbon dioxide pulse, triggering not only a drastic temperature increase, but widespread ocean acidification and anoxia.

According to the study, during the event, eight percent of the global seafloor -- an area three times that of the United States -- became completely anoxic.  The pH dropped so much that animals with calcium carbonate exoskeletons literally dissolved.  Rainfall patterns shifted dramatically, impacting terrestrial biomes as well.  By the time things began to recover, it was a changed world, all in a matter of a half of a million years.

Ready for the punchline? 

Today's rate of carbon dioxide increase in the atmosphere is over two hundred times what it was during the Toarcian Extinction Event.

Twenty thousand gigatons in five hundred thousand years is a lot, and had a devastating effect on the world's ecosystems; we've put two thousand gigatons into the atmosphere in the past two hundred years.  

Is it any surprise why the scientists have been trying like hell to get everyone's attention?

"We just don't have anything this severe [in the geological record]," said paleoclimatologist Michael Kipp, who co-authored the study.  "We go to the most rapid CO2-emitting events we can in history, and they're still not rapid enough to be a perfect comparison to what we're going through today. We're perturbing the system faster than ever before.  We have at least quantified the marine oxygen loss during this event, which will help constrain our predictions of what will happen in the future."

None of this is meant to stun people into giving up.  We have got to get a handle on this.  Yes, we've crossed several benchmarks the climate scientists have warned us about.  But every tenth of a degree's further increase we can prevent will mitigate the effects of what we're doing.  We have got to stop electing politicians who shrug their shoulders about anthropogenic climate change, most strikingly Florida's belligerent and willfully stupid Governor Ron DeSantis, who recently signed a law striking any mention of climate change in state statutes, banning offshore wind turbines, and deregulating natural gas production, transport, and use.  

In one of the lowest-lying, most hurricane-prone states in the country.

Maybe it will take our getting slapped hard to wake us up; we don't have a good record of addressing problems that aren't right in front of our faces.  Events like the massive heat dome that just cooked the southern, central, and northeastern states are just the beginning, and are easily forgotten once they pass.  They're predicting a vicious hurricane season, fueled by a central Atlantic with a surface the temperature of bath water, but we've seen dire predictions before and gone on our way as if nothing was amiss.

So how many lives will it cost before that wake-up call is finally listened to?

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The long rain

Imagine going back 240 million years.

This would land you in the early Triassic Period.  By this time, the Earth would have had twelve million years to recover from the cataclysmic Permian-Triassic Extinction, the largest mass extinction on record.  Life had rebounded some -- two of the dominant terrestrial animal groups were the terrifying crurotarsans (picture a long-legged on-land crocodile) and the dicynodonts (which looked a little like a rhino with a parrot's bill -- and tusks).

Finding your way around the place would be confusing, if all you know is the current continental arrangement.  Pangaea was still locked together, and would be until rifting began to open up the Atlantic Ocean -- but that was still forty million years in the future.

[Image licensed under the Creative Commons Fama Clamosa, Pangaea 200Ma, CC BY-SA 4.0]

Because virtually all the land masses of the world were jammed together into one supercontinent, the climate was really dry.  There probably was a reasonable amount of rainfall along the coastline, but most places were very far away from the coast.  The result is that one of the major early Triassic sedimentary rocks is the "Triassic red sandstone" formed from wind-blown layers of sand deposited in conditions that resembled today's Sahara Desert.  But instead of being restricted to a part of a single continent, this was what it was like in the interior of Pangaea -- i.e., the entire land mass on planet Earth.

But even the Sahara isn't lifeless, and neither was the continental interior of Pangaea during the early Triassic.  Organisms found a way to cope with the dry conditions, and -- all things considered -- life was doing okay.

Then -- 234 million years ago -- it started to rain.

I'm not talking about your short-lived desert thunderstorm, here, nor even the kind of "atmospheric river" event that hit the Central Valley of California this year, causing not only flooding but an explosive burst of wildflowers.

This rainstorm lasted two million years.

It's called the "Carnian Pluvial Episode," and evidence for it can be seen in a sudden shift in sedimentary geology, a change in the isotope concentrations in carbonate rocks (like limestone), and a huge spike in heavy elements (like osmium and mercury) that are much more common in deep-mantle rocks.  The last bit is a clue to what happened -- there was a massive eruption called the Wrangellia Flood Basalts in what would eventually become southern Alaska and western British Columbia.  I've written before about two other flood basalt provinces, the Siberian Traps (implicated in the Permian-Triassic Extinction) and the Deccan Traps (contributory to the Cretaceous Extinction), and while the Wrangellia event isn't as big as either of those, it is many orders of magnitude larger than anything you probably picture as a volcanic eruption.  The Wrangellia Flood Basalt injected huge quantities of carbon dioxide into the atmosphere, largely through the lava burning through limestone, coal, and any organic matter on the surface.  This spiked the atmospheric temperature, increased seawater evaporation...

... and it started to rain.

Imagine being an animal adapted to living in Arizona, and all of a sudden, you find you're living in the Amazon lowlands.  That's pretty much what happened.

The result was another extinction.  Both the crurotarsans and dicynodonts bit the dust.  Or actually, at that point, the mud.  Let me emphasize that both groups were doing fine before the climatic shift; but having spent millions of years adapting to the early Triassic desert conditions, they couldn't handle it when the long rain started.

The winners here were the animals that had the flexibility to cope with the changing conditions -- in this case, dinosaurs, which would go on to dominate the place for another 165 million years.  The early mammals also made it, obviously, but they were still small at this point (and would remain so until the non-avian dinosaurs met their demise).  Interesting that the quintessential Mesozoic group, the dinosaurs, might never have taken off like they did if it hadn't been for a sudden geological event that triggered a climatic shift and knocked out the two main competitor groups.

And I would be remiss if I didn't mention that the rate at which the Wrangellia Flood Basalts injected carbon dioxide into the atmosphere is thought to be significantly smaller than the rate we're doing the same from burning fossil fuels.

Any wonder why environmentalists are worried?

We've already had our share of bizarre weather in the last few years; it seems like not a week goes by without my hearing someone say, "This hardly ever happens."  At the moment, here in upstate New York, it hasn't rained for a month, and we're getting spectacular sunsets (and difficulty breathing) because of a pall of wildfire smoke that's come all the way from central Quebec.  Vietnam and Laos have already set record high temperatures this year, reaching a devastating 44 C (with correspondingly high humidity), as did the Pacific Northwest of the United States, with Portland at a less dangerous but still scorching 35 C.  

Weather isn't climate, something I feel obligated to remind the climate change deniers every time we have a cold snap in January; but as anomalous weather happens over and over and over, these kinds of patterns begin to add up to something significant.  As a Louisiana native, I'm already worried about this year's hurricane season -- especially given that the most recent sea surface temperatures are (in the words of Australian climatologist Matthew England) "heading off the charts."

To judge by the geological record of events like the Carnian Pluvial Episode, it looks like we might be in the last half of "fuck around and find out."

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The terrible cost of inaction

I try not to be a one-issue voter, but it would be very hard for me to support a candidate for state or federal office who is not explicitly in favor of addressing the causes of anthropogenic climate change.

The jury is still out, of course, as to whether we might already be too late to avoid some of the worst repercussions.  The temperature is climbing at a rate not seen since the globally-catastrophic Paleocene-Eocene Thermal Maximum 55-some-odd million years ago, and it's possible that the rate of the increase we're seeing now is actually higher.

And yet our politicians sit on their hands.  "The scientists are still uncertain" -- despite the fact that the ones harping on all the doubt are the mouthpieces of the fossil fuel industry, who are scared stiff that there'll be an administration that actually takes climate change seriously.  "It's a natural warm-up" -- despite mountains of evidence that this alteration in the climate is caused by man-made greenhouse gases like carbon and methane.  "It'd cost too much to fix" -- despite the fact that the cost of not doing anything is projected to run into the trillions of dollars.  (More on that in a moment.)  And -- most maddening of all -- "it was cold in January so the world isn't warming" -- which you hear from politicians who evidently failed ninth-grade earth science and never figured out the difference between "weather" and "climate."

We had two more pieces of research recently published that highlight how dire the situation has become.  In the first, a team led by Eric Rignot of the University of California - Irvine showed that the rate of ice loss from Greenland -- which has the world's second-largest on-land ice sheet -- has increased sixfold in the last fifty years.  Between 1980 and 1990, an estimated 51 billion tons of ice melted from the Greenland Ice Sheet; between 2010 and 2018 -- a two-year shorter time span -- 286 billion tons melted.  Of the rise in sea level attributable to Greenland ice melt, over half of it has occurred in the last eight years.

[Image licensed under the Creative Commons Christine Zenino from Chicago, US, Greenland Ice Sheet, CC BY 2.0]

In an interview in the Washington Post, Rignot was unequivocal:

The 1980s marked the transition time when the Earth’s climate started to drift significantly from its natural variability as a result of man-made emissions of greenhouse gases...  The entire periphery of Greenland is affected.  I am particularly concerned about the northern regions, which host the largest amount of potential sea-level rise and are already changing fast. 

In Antarctica, some big sleeping giants in East Antarctica are waking up, in addition to a large part of West Antarctica being significantly affected. None of this is good news.  We ought to prepare ourselves for what is coming up and take action as soon as possible to avoid the most drastic scenarios.

The second study, led by climatologist Dmitry Yumashev of Lancaster University, looked at it from the perspective of the only thing that seems to motivate most politicians -- money.  The authors write:

Arctic feedbacks accelerate climate change through carbon releases from thawing permafrost and higher solar absorption from reductions in the surface albedo, following loss of sea ice and land snow.  Here, we include dynamic emulators of complex physical models in the integrated assessment model PAGE-ICE to explore nonlinear transitions in the Arctic feedbacks and their subsequent impacts on the global climate and economy under the Paris Agreement scenarios.  The permafrost feedback is increasingly positive in warmer climates, while the albedo feedback weakens as the ice and snow melt.  Combined, these two factors lead to significant increases in the mean discounted economic effect of climate change: +4.0% ($24.8 trillion) under the 1.5 °C scenario, +5.5% ($33.8 trillion) under the 2 °C scenario, and +4.8% ($66.9 trillion) under mitigation levels consistent with the current national pledges.

Catch that?  Under the best case scenario, the economic cost by 2100 is projected at almost twenty-five trillion dollars.  That's "trillion," with a "t."  And the current Paris Agreement pledges don't even meet that.  If all the signatories meet their pledged targets for carbon emission, the cost is projected to be well over twice that.

Oh, and the United States, one of the top carbon emitters in the world, withdrew from the Paris Agreement in June of 2017 under an explicit directive from Donald Trump, using the excuse that the mandated targets would be "too expensive" and "economically disastrous for the United States."

You want to see economic disaster, Mr. Trump?  You ain't seen nothing yet.  Wait till rising sea levels start inundating coastal cities, requiring massive relocation.  And from the Rignot et al. study referenced above, the wait may not even be that long.

"It’s disheartening that we have this in front of us," Yumashev said in an interview with The Guardian.  "We have the technology and policy instruments to limit the warming but we are not moving fast enough."

Disheartening?  I'd call it "alarming," myself.

I know I've rung the changes on this topic many times, but I feel duty-bound to keep bringing it up because our leaders are still not doing anything.  There's been some lip-service to addressing climate change, but the propaganda machine that is bound and determined to label any recommendations for mitigation as left-wing ultra-green economically unfeasible claptrap has worked all too well.  So don't expect this to be the last time you hear about it here -- and, hopefully, elsewhere.  We'll keep yelling until the politicians wake up or get voted out of office.

It's too important an issue to do otherwise.

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This week's Skeptophilia book recommendation is a classic, and is pure fun: Man Meets Dog by the eminent Austrian zoologist and ethologist Konrad Lorenz.  In it, he looks at every facet of the human/canine relationship, and -- if you're like me -- you'll more than once burst out laughing and say, "Yeah, my dog does that all the time!"

It must be said that (as the book was originally written in 1949) some of what he says about the origins of dogs has been superseded by better information from genetic analysis that was unavailable in Lorenz's time, but most of the rest of his Doggy Psychological Treatise still stands.  And in any case, you'll learn something about how and why your pooches behave the way they do -- and along the way, a bit about human behavior, too.

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

Piercing the clouds

One of the most unusual stories that H. P. Lovecraft ever wrote is "In the Walls of Eryx."  It isn't the usual soul-sucking eldritch nightmares from the bubbling chaos at the center of the universe; in fact, it's his only real science fiction story.  It centers around a human colony on Venus, devoted to mining a kind of crystal that can be used for propulsion.  There's an intelligent native species -- reptilian in appearance -- who was content to let the humans bump around in their space suits (Lovecraft at least got right that the atmosphere would be toxic to humans) until the humans started killing them.  At that point, they started fighting back -- and setting traps.

The story centers around a crystal hunter who is out on an expedition and sees a huge crystal in the hands of a (human) skeleton.  He goes toward it, and bumps into an unseen obstacle -- completely transparent walls, slick (and therefore unclimbable) and twelve feet tall (so unjumpable).  The problem is, when he tries to back out, he's already moved around a bit, and doesn't retrace his steps perfectly.

Then he runs into another wall.

What's happened is that he's stumbled into an invisible labyrinth.  And how do you find your way out of a maze if you can't see it?  You'll just have to read it.  It's only a dozen or so pages long, and is one of the neatest (and darkest) puzzle-box stories you'll ever pick up.

It's been known since Lovecraft's time ("In the Walls of Eryx" was written in 1936) that Venus was covered by clouds, and its surface was invisible from Earth.  Of course, a solid mantle of clouds creates a mystery about what's underneath, and speculation ran wild.  We have Lovecraft's partially-correct solution -- a dense, toxic atmosphere.  Carl Sagan amusingly summed up some of the early thinking on Venus in the episode "Heaven and Hell" from his groundbreaking series Cosmos: "I can't see a thing on the surface of Venus.  Why not?  Because it's covered with a dense layer of clouds.  Well, what are clouds made of?  Water, of course.  Therefore, Venus must have an awful lot of water on it.  Therefore, the surface must be wet.  Well, if the surface is wet, it's probably a swamp.  If there's a swamp, there's ferns.  If there's ferns, maybe there's even dinosaurs...  Observation: I can't see anything.  Conclusion: dinosaurs."

Of course, reputable scientists didn't jump to these kinds of crazy pseudo-inferences.  As Neil deGrasse Tyson points out, "If you don't know, then that's where your conversation should stop.  You don't then say that it must be anything."  (Perhaps not a coincidence that Tyson was the host of the reboot of Cosmos that appeared two years ago.)

The first hint that Venus was not some lush tropical rain forest came in the late 1950s, when it was discovered that there was electromagnetic radiation coming from Venus that only made sense if the surface was extremely hot -- far higher than the boiling point of water.  This was confirmed when the Soviet probe Venera 9 landed on the surface, and survived for 127 minutes before its internal circuitry fried.

In fact, saying it's "hot" is an understatement of significant proportions.  The average surface temperature is 450 C -- 350 degrees higher than the boiling point of water, and hot enough to melt lead.  The atmosphere is 96.5% carbon dioxide (compared to 0.04% in the Earth's atmosphere), causing a runaway greenhouse effect.  Most of the other 3.5% is nitrogen, water vapor, and sulfur dioxide -- the latter being the rotten-egg chemical that, when mixed with water, creates sulfuric acid.

Yeah.  Not such a hospitable place.  Even for crystal-loving intelligent reptiles.

Photograph from the surface of Venus [Image is in the Public Domain, courtesy of NASA/JPL]

But there's still a lot we don't know about it, which is why at the meeting last fall of the American Geophysical Union, there was a proposal to send a probe to our nearest neighbor.  But this was a probe with a difference; it would be attached to a balloon, which would keep it aloft, perhaps indefinitely given the planet's horrific convection currents.  From there, we could not only get photographs, but more accurate data on the atmospheric chemistry, and possibly another thing as well.

One of the things we don't know much about is the tectonics of the planet's surface.  There are clearly a lot of volcanoes -- unsurprising given how hot it is from other causes -- but whether the crust is shifting around the way it does on Earth is not known.  One way to find out would be looking for "venusquakes" -- signs that the crust was unstable.  But how to find that out when probes on the surface either melt or get dissolved by the superheated sulfuric acid?

The cool suggestion was that because of the atmosphere's density, it might be "coupled" to the surface.  So if something shook the surface -- a venusquake or volcanic eruption -- those waves might be transferred to the atmosphere.  (This effect is insignificant on Earth because our atmosphere is far, far less dense.)  Think of a plate with a slab of jello on it -- if you shake the plate, the vibrations are transferred into the jello because the whole thing is more or less stuck together, so the surface of the jello wobbles in resonance.

An airborne probe might be able to tell us something about Venus's geology, which is pretty awesome.  It appeals not only to my fascination with astronomy, but my love of a good mystery, which the second planet definitely is.

So I hope this project gets off the ground, both literally and figuratively.  Even if it's unlikely to detect anything living -- reptilian or not -- we could learn a great deal about what happens when the carbon dioxide levels start undergoing a positive feedback.

A scenario we all would like very much not to repeat here at home.

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This week's Skeptophilia book recommendation is a tour-de-force for anyone who is interested in biology -- Richard Dawkins's The Ancestor's Tale.  Dawkins uses the metaphoric framework of The Canterbury Tales to take a walk back into the past, where various travelers meet up along the way and tell their stories.  He starts with humans -- although takes great pains to emphasize that this is an arbitrary and anthropocentric choice -- and shows how other lineages meet up with ours.  First the great apes, then the monkeys, then gibbons, then lemurs, then various other mammals -- and on and on back until we reach LUCA, the "last universal common ancestor" to all life on Earth.

Dawkins's signature lucid, conversational style makes this anything but a dry read, but you will come away with a far deeper understanding of the interrelationships of our fellow Earthlings, and a greater appreciation for how powerful the evolutionary model actually is.  If I had to recommend one and only one book on the subject of biology for any science-minded person to read, The Ancestor's Tale would be it.

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