The shifting sands

In H. P. Lovecraft's wildly creepy story "The Shadow Out of Time," we meet a superintelligent alien race called the Yith who have a unique way of gathering information.

The Yith, who lived in what is now Australia's Great Sandy Desert some 250 million years ago, are capable of temporarily switching personalities with other intelligent beings throughout the cosmos and from any time period.  While the consciousness of the kidnapped individual is residing in its temporary Yith body, it enjoys the freedom to learn anything it wants from the extensive library of information the Yith have gleaned -- as long as the individual is willing to contribute his/her own knowledge to the library.  The main character, early twentieth century professor Nathaniel Peaslee, is switched, and while he is living with the Yith he meets a number of luminaries whose personalities have also been swiped, including:

• Titus Sempronius Blaesus: a Roman official from 80 B.C.E.
• Bartolomeo Corsi: a twelfth-century Florentine monk
• Crom-Ya: a Cimmerian chief who lived circa 15,000 B.C.E.
• Khephnes: a Fourteenth Dynasty (circa 1700 B.C.E.) Egyptian pharaoh
• Nevil Kingston-Brown: an Australian physicist who would die in 2518 C.E.
• Pierre-Louis Montagny: an elderly Frenchman from the time of Louis XIII (early seventeenth century)
• Nug-Soth: a magician from a race of conquerors in16,000 C.E,
• S'gg'ha: a member of the star-headed "Great Race" of Antarctica, from a hundred million years ago
• Theodotides: a Greco-Bactrian official of 200 B.C.E.
• James Woodville: a Suffolk gentleman from the mid-seventeenth century
• Yiang-Li: a philosopher from the empire of Tsan-Chan, circa 5000 C.E.

Compared to most of the gory dismemberments other Lovecraftians entities were fond of, the Yith are remarkably genteel in their approach.  Of course, it's not without its downside for the kidnapped individual; not only do they lose control over their own bodies for a period up to a couple of years, they experience serious disorientation (bordering on insanity in some cases) upon their return to their own bodies.

Nevertheless, it's a fantastic concept for a story, and I remember when I first read it (at about age sixteen) how taken I was with the idea of being able to meet and talk with individuals from both past and future, not to mention other species. But what struck me most viscerally when I read it was when Peaslee, in the Yith's body, describes what he sees surrounding the library.

It's a tropical rain forest.  What now is a barren desert, with barely a scrap of vegetation, was a lush jungle:

The skies were almost always moist and cloudy, and sometimes I would witness tremendous rains.  Once in a while, though, there would be glimpses of the Sun -- which looked abnormally large -- and the Moon, whose markings held a touch of difference from the normal that I could never fathom.  When -- very rarely -- the night sky was clear to any extent, I beheld constellations which were nearly beyond recognition.  Known outlines were sometimes approximated, but seldom duplicated; and from the position of the few groups I could recognize, I felt I must be in the Earth's southern hemisphere, near the Tropic of Capricorn.

The far horizon was always steamy and indistinct, but I could see that great jungles of unknown tree ferns, Calamites, Lepidodendron, and Sigillaria lay outside the city, their fantastic fronds waving mockingly in the shifting vapors...  I saw constructions of black or iridescent stone in glades and clearings where perpetual twilight reigned, and traversed long causeways over swamps so dark I could tell but little of their towering, moist vegetation.

[Image licensed under the Creative Commons Carl Malamud, Cretaceous Diorama 2, CC BY 2.0]

I think it's the first time I'd really gotten hit square between the eyes with how different the Earth is now than it had been, and that those changes haven't halted. In the time of Lovecraft's Yith, 250 million years ago, where I am now (upstate New York) was underneath a shallow saltwater ocean.  Only a hundred thousand years ago, where my house stands was covered with a thick layer of ice, near the southern terminus of the enormous Laurentide Ice Sheet.  (In fact, the long, narrow lakes that give the Finger Lakes Region its name were carved out by that very glacier.)

I was immediately reminded of that moment of realization when I read a paper in Nature called "Temperate Rainforests Near the South Pole During Peak Cretaceous Warmth," by a huge team led by Johann Klages of the Alfred-Wegener-Institut Helmholtz-Zentrum für Polar und Meeresforschung, of Bremerhaven, Germany.  Klages's team made a spectacular find that demonstrates that a hundred million years ago, Antarctica wasn't the windswept polar desert it currently is, but something more like Lovecraft's vision of the site of the prehistoric library of Yith.  The authors write:

The mid-Cretaceous period was one of the warmest intervals of the past 140 million years, driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume.  In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions.  Here we use a sedimentary sequence recovered from the West Antarctic shelf—the southernmost Cretaceous record reported so far—and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82° S during the Turonian–Santonian age (92 to 83 million years ago).  This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores.  A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120–1,680 parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide.

It's a stunning discovery from a number of perspectives.  First, just the wonderment of realizing that the climate could change so drastically.  Note that this wasn't, or at least wasn't entirely, because of tectonic movement; the site of the find was still only eight degrees shy of the South Pole even back then.  Despite that, the warmth supported a tremendous assemblage of life, including hypsilophodontid dinosaurs, labyrinthodontid amphibians, and a diverse flora including conifers, cycads, and ferns.  (And given that at this point Antarctica and Australia were still connected, Lovecraft's vision of the home of the Yith was remarkably accurate.)

So, if it wasn't latitude that caused the warm climate, what was it?  The other thing that jumps out at me is the high carbon dioxide content of the atmosphere back then -- 1,000 parts per million.  Our current levels are 410 parts per million, and going up a steady 2.5 ppm per year.  I know I've rung the changes on this topic often enough, but I'll say again -- this is not a natural warm-up, like the Earth experienced during the mid-Cretaceous.  This is due to our out-of-control fossil fuel use, returning to the atmosphere carbon dioxide that has been locked up underground for hundreds of millions of years.  When the tipping point will occur, when we can no longer stop the warm up from continuing, is still a matter of debate.  Some scientists think we may already have passed it, that a catastrophic increase in temperature is inevitable, leading to a complete melting of the polar ice caps and a consequent rise in sea level of ten meters or more.

What no informed and responsible person doubts any more is that the warm-up is happening, and that we are the cause.  People who are still "global warming doubters" (I'm not going to dignify them by calling them skeptics; a skeptic respects facts and evidence) are either woefully uninformed or else in the pockets of the fossil fuel interests.

I don't mean to end on a depressing note.  The Klages et al. paper is wonderful, and gives us a vision of an Earth that was a very different place than the one we now inhabit, and highlights that what we have now is different yet from what the Earth will look like a hundred million years in the future.  It brings home the evocative lines from Alfred, Lord Tennyson's wonderful poem "In Memoriam:"

There rolls the deep where grew the tree.
O Earth, what changes hast thou seen?
There where the long road roars hath been
The stillness of the central sea.
The hills are shadows, and they flow
From form to form, and nothing stands;
They melt like mist, the solid lands,
Like clouds, they shape themselves and go.

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Thawing the snowball

One of the frightening things about a system in equilibrium is what happens when you perturb it.

Within limits, most systems can recover from perturbation through some combination of negative feedbacks.  An example is your body temperature.  If something makes it goes up -- exercise, for example, or being outside on a hot, humid day -- you sweat, bringing your temperature back down.  If your body temperature goes down too much, you increase your rate of burning calories, and also have responses like shivering -- which brings it back up.  Those combine to keep your temperature in a narrow range (what the biologists call homeostasis).

Push it too much, though, and the whole thing falls apart.  If your temperature rises beyond about 105 F, you can experience seizures, convulsions, brain damage -- or death.  Your feedback mechanisms are simply not able to cope.

This, in a nutshell, is why climate scientists are so concerned about the effects of anthropogenic carbon dioxide.  Within limits -- as with your body temperature -- an increase in carbon dioxide results in an increase in processes that remove the carbon dioxide from the atmosphere, and the whole system stays in equilibrium.  There is a tipping point, however.

The problem is that no one knows where it is -- and whether we may have already passed it.

A new piece of research from the Virginia Polytechnic Institute has indicated that this flip from stability to instability may be fast and unpredictable.  A paper authored by a team led by paleobiologist Shuhai Xiao, that came out last month in Geology, looks at one of the main destabilization events that the Earth has ever experienced -- when the "Snowball Earth" thawed out in the late Precambrian Period,  635 million years ago.

Artist's conception of the Precambrian Snowball Earth [Image is in the Public Domain, courtesy of NASA/JPL]

Xiao and his team studied rocks from Yunnan and Guizhou, China, that are called cap carbonates.  They are made of limestone and dolomite and are deposited quickly in marine environments when the carbon dioxide content of the atmosphere spikes, leading to a dramatic temperature increase and a subsequent increase in absorption of carbonates into seawater (and ultimately deposition of those carbonates on the seafloor).  The cap carbonates Xiao et al. studied were dated to between 634.6 and 635.2 million years old, which means that the entire jump in both temperature and carbon dioxide content took less than 800,000 years.

So in less than a million years, the Earth went from being completely covered in ice to being subtropical.  The jump in global average temperature is estimated at 7 C -- conditions that then persisted for the next hundred million years.

Xiao et al. describe this as "the most severe paleoclimatic [event] in Earth history," and that the resulting deglaciations worldwide were "globally synchronous, rapid, and catastrophic."

Carol Dehler, a geologist at Utah State University, is unequivocal about the implications.  "I think one of the biggest messages that Snowball Earth can send humanity is that it shows the Earth’s capabilities to change in extreme ways on short and longer time scales."

What frustrates me most about today's climate change deniers is that they are entirely unwilling to admit that the changes we are seeing are happening at an unprecedented rate.  "It's all natural," they say.  "There have been climatic ups and downs throughout history."  Which is true -- as far as it goes.  But the speed with which the Earth is currently warming is faster than what the planet experienced when it flipped between an ice-covered frozen wasteland and a subtropical jungle.  It took 800,000 years to see an increase of the Earth's average temperature by 7 degrees C.

The best climate models predict that's what we'll see in two hundred years.

And that is why we're alarmed.

It's unknown what kind of effect that climate change in the Precambrian had on the existing life forms.  The fossil record just isn't that complete.  But whatever effect it had, the living creatures that were around when it happened had 800,000 years to adapt to the changing conditions.  What's certain is that an equivalent change in two centuries will cause massive extinctions.  Evolution simply doesn't happen that quickly.  Organisms that can't tolerate the temperature fluctuation will die.

We can only speculate on the effects this would have on humanity.

This is clearly the biggest threat we face, and yet the politicians still sit on their hands, claim it's not happening, that remediation would be too costly, that we can't prevent it, that short-term profits are more important than the long-term habitability of the Earth.  Our descendants five hundred years from now will look upon the leaders from this century as having completely abdicated their responsibility of care for the people they represent.

Presuming we still have descendants at that point.

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This week's Skeptophilia book recommendation combines science with biography and high drama.  It's the story of the discovery of oxygen, through the work of the sometimes friends, sometimes bitter rivals Joseph Priestley and Antoine Lavoisier.   A World on Fire: A Heretic, an Aristocrat, and the Race to Discover Oxygen is a fascinating read, both for the science and for the very different personalities of the two men involved.  Priestley was determined, serious, and a bit of a recluse; Lavoisier a pampered nobleman who was as often making the rounds of the social upper-crust in 18th century Paris as he was in his laboratory.  But despite their differences, their contributions were both essential -- and each of them ended up running afoul of the conventional powers-that-be, with tragic results.

The story of how their combined efforts led to a complete overturning of our understanding of that most ubiquitous of substances -- air -- will keep you engaged until the very last page.

[Note:  If you purchase this book by clicking on the image/link below, part of the proceeds will go to support Skeptophilia!]