Monday, February 17, 2014

Part 2 -- How Humanity Saved the Biosphere. The Decadence of the Pleistocene Biosphere [First Part].

To My Readers,

Below is the second part of my multi-part re-rendition, in this blog, of a classic text, written by an anonymous collective author, one which -- very early-on, in the 1970s -- '''smelled a rat [smelled the 'Rocke-Nazi' rat, in my opinion, the biggest, rottenest rat in all of human [pre-]history to-date -- the most rabid, the most massively "ambitious" mass torturers, and mass murderers, in all of human history, who make the bloody Vlad The Impaler pale to an infinitesimal in comparison] in the "Global Warming", "People Are Pollution" rap''', and circulated, in <<samizdat>> fashion, a rather comprehensive warning to humanity about this new "eu"-genocidal ploy, until years later, when an updated version of this text became available on the world wide web.

This text is entitled --

Crises by Nature:  How Humanity Saved the Biosphere   

For the Resumption of Humanity's Ascent, and, with it -- and by it -- the Regeneration of Our Planetary Biosphere,

M. Milankovitch

Crises by Nature
How Humanity Saved The Biosphere

Capitalist Crisis Studies
[with modifications by M. Milankovitch]

Table of Contents

III - The Decadence of the Pleistocene Biosphere 
[first part]

What we are trying to do, here, now, is to uncover the hidden history of the biosphere — hidden, blocked from view, at least, for the pervasive ideology of Nature which still characterizes much of modern science; an ideology of ‘equilibriumism which unspokenly assumes only stasis, balance, and pre-established harmony in Nature, and is blinded to dialectical patterns by that pre- and contra-empirical presumption. 

What we are trying to determine is: What has really been underway in the last 280 million years — what has been the summary content, the dominant theme, the major trend, of the history of Nature on this planet in that time?

There is mounting evidence — evidence discernible, at any rate, to the dialectical eye, expecting not equilibrium, stasis, permanence, but dynamism, self-contradiction, self-change, evolution — that the biosphere, the photosynthetically-centered stage of it, had already reached its peak in the Carboniferous period, long before the advent of man, and has been in decline ever since; that the human species as we know it -- whose first tracks, those of scattered stragglers staggering out of the blizzard, we can pick out against the opaque white background of the great Pleistocene Ice [see
Graphics 5, 8, 9, 10, 11) -- that this human species was born into a dying world.

The remaking of that world, the restoration of ecological prosperity to that planet, then depends, evidently, on what that newest -- human -- species will do. 

If ecological prosperity is ever to be restored on Earth, if the biosphere is to halt its self-destruction, and attain to a state of vigorous health again, it evidently must be through the agency of that -- human -- species, within Nature; through its redesigning of the Natural World, through its solving the contradictions of that world (including including those within its own portion of that world).

Typical contemporary plants grow faster, healthier, fuller in an atmosphere many times as rich in CO2 as the present one c5, suggesting a long, ancient adaptation to a climate much different from that which prevails today, for an atmosphere richer in CO2 would tend to be a warmer one. 

Of late c6, great bald patches have begun to appear in the forestrial living fur coat of the planet — the gigantic deserts — which, like the Sahara, are continuing a geologically rapid growth.  

Before this balding set in, successive walls of ice had invaded the lower latitudes from both poles, lacerating the great rain forests and beating them back to a narrow equatorial band; melting back again but leaving great desolations of desert in their wake, desertifications which global-cooling-caused drought had already initiated during the prelude to the Great Ice. 

For some reason — CO2 deficiency and cooling global climate? — the great forests lacked the vitality to spread out once again from their equatorial respite and reconquer lost ground, so the ice was replaced instead by arid waste, grassland, or temperate forest, all much less prosperous ecosystems in "primary productivity", rate-of-photosynthesis terms.

In the long view, and in terms of the prime vital sign of this form of the biosphere, which is "biomass primary productivity", or the rate of photosynthesis, controlling the rate of reproduction or self-accumulation of living mass, this is a picture of a world in decline, of a life-bearing planet committing suicide.

We can readily envision the final scenario  --

The climate continues to deteriorate as the CO2 level continues to fall. 

Glaciations grow more frequent and more severe. 

The ice retreats for a time after each onslaught, thrown back by the saturation nonlinearities, the negative feedbacks, or inhibitory self-effects, which a vast glacier system develops against itself once it grows beyond a certain extent. c7 

But each time it gathers greater force, laying siege anew to the tropics and cutting deeper into the last fastness of the once great global forest.  

Finally, the twin equator-ward pincers of the two polar caps meet, clanging shut like frigid, icicle-fanged jaws over the world of life they have just devoured.  

Having broken through the last defenses of the plant world, marine and continental alike, and, with that, of the life-world, of the biosphere, as a whole, all that would remain would be the mopping up of isolated pockets of biology — spores, seeds, micro-organisms — which could not long hold out beyond this, the biospheres mediated self-destruction of its own photosynthetic basis.  

In the end: a sterilized planetary surface, alternately frozen or arid, but shaved clean, by an ice-edged razor, of that mantle of life which once adorned it with such luxuriance and promise, with life persisting only in the loci of ocean floor "black smokers", and in the form of deep subterranean lithotrophic, etc., archaeo-bacteria, for as long as the inner self-heating of the Earth, via radioactive decay and naturally-arising fission reactors, continues!

That is the scenario, unless we stop it!

Now let us examine the evidence behind it. 

According to available information, the last 3 million years of Earths history, called the Quaternary period (refer to Graphics 5, 8, 9, 10, 11), has been a time of unusually harsh climate. c8  

In fact, through most of Earths history as a '''biotic''', or life-bearing, planet, tropical conditions prevailed over most of its surface:

... one conclusion seems inescapable. This is that the present restriction of tropical climates to a relatively narrow belt (and in periods of glaciation to an even narrower belt) of the Earths surface is an unusual situation.
The evidence of the Cretaceous and Tertiary indicates that for most of the time prior to the Pliocene the tropical zone was more widespread than now and that during certain intervals at least the boundary of the tropics was at some point between 50o and 60o N latitude in the northern hemisphere and occupied a similar position in the southern hemisphere...
...the conclusions of various workers, such as...[MM -- long list follows] indicate that a more widespread tropical or warm” climate prevailed over much of the Paleozoic,  Mesozoic, and Tertiary [MM -- i.e., for most of the last 500+ million years since the dawn of photosynthetic life before the Cambrian Period — see Graphics 5, 8, 9, 10, 11, reproduced here from the text]. c9
And temperate forests extended deep into both polar regions --

The luxuriant growth of broad-leaf hardwood forests in high Arctic latitudes persisted from the Cretaceous into the Eocene and probably the Oligocene, indicating a prolonged continuation of humid warm temperate, or at least temperate forest climate in the polar regions.
Evidence for this may be found in both Arctic and Antarctic regions.
During the early Cenozoic the northern mid-latitudes were covered by vegetation, the botanical equivalent of which is now confined to sub-tropical and even tropical climates. c10

The polar regions at that time were iceless --

From all we know, the Quaternary represents an exceptional period in the history of our globe.
The repeated advance and retreat of glaciation is a phenomenon specifically restricted to this period: before that, for a time interval of about 200 million years, there was almost no permanent ice on the earths surface: even the poles were free and enjoyed a temperate or cold-temperate climate... .
[MM -- note:  this passage was written before the discovery of the full "Snowball Earth" evidence].
In any case it is now clear that the ice ages represent cases of a general deterioration of the climate of our globe. c11

During this long warm period of the last 130 million years and more, two successive intercontinental forests clothed the globe, of which today we know only tattered remnants. 

The earlier of these two was tropical --
At the beginning of the Tertiary, the continent was relatively low and relatively uncut by the many mountain ranges of today.
There were only three main ranges:  two in the Rocky mountains, and one in the Appalachian region.
Everything west of the present Utah-Nevada line was relatively low country with relatively even and mild climates.
Tropical forests extended as far north as the state of Washington, and Alaska was covered with temperate forests of redwood and other species.
These warm and uniform conditions across the continent eventually came to a gradual close with volcanic activity and a cooling of the climate in Miocene times and ended in another great period of mountain-building during the very late Pliocene and Pleistocene within the last million years or so.c12

In the wake of the great cooling, a temperate forest succeeded this inter-continental jungle, but a temperate forest whose grandeur surpassed by far that of any seen on this planet since, let alone that of the — comparatively speaking — mere pockets of forest we know today --

Taking the place of the tropical forests in the North, the transcontinental temperate forest moved down from Alaska and northern Canada.
This northern Miocene forest was the most magnificent temperate forest of all time.
It not only was essentially transcontinental from the Southern Appalachians to Washington and Oregon but, with variations, extended clear around the Northern Hemisphere so that it was well developed also in Europe and Asia.
Dr. Chaney has called it the Arcto-Tertiary forest.
In middle Miocene times, it extended down the west coast as far as central California and south central Nevada, where it bordered on the Madro-Tertiary woodland.

The Arcto-Tertiary forest was so big geographically that it was bound to vary in composition from one place and time to another.
No temperate forest in the world today is exactly like the Arcto-Tertiary forest.
However, if one walks through the cove hardwood forests of the Great Smoky Mountains of eastern Tennessee and western Carolina, he [ed: one] will get some idea of what the Arcto-Tertiary forest was like.
Another forest quite like parts of the Arcto-Tertiary forest is the coastal redwood forest of northern California...”. c13

The later history of this forests life unfolds as a vast story of Nature at war with itself, of a planet-spanning battle between Green and White, a war of the forest versus the desert and the great Ice for predominance in the occupation of the surface of the Earth --

Within the last million years or so, the climates of Western North America began to turn much colder and drier....
Not only did the climate become colder and drier but the rainfall pattern changed.
Instead of rainfall being evenly distributed throughout the year with plenty of summer rainfall, there was a shift toward winter precipitation and very little rain during the summer.
This pattern persists today... .
These climatic changes had pronounced effects on the vegetation.
The Arcto-Tertiary forest disappeared over much of its range... .
Great grasslands, with herds of hoofed mammals such as the horse and camel, replaced the forest east of the Sierra and extended far into the interior of the continent.... c14

About this time, the troubles begin to show, and the first rumblings of the coming war were sounded, by by the Ice Age heralds of drought and desertification --

In late Pliocene and Peistocene times, some 1 or 2 million years ago, with the Sierra rising rapidly, the climates became even more arid.
From the retreating subtropical Madro-Tertiary flora, from the Arcto-Tertiary flora, and from the high mountains, new kinds of plants evolved that fitted the extremely dry conditions.
Up to this time, there had been no real desert climate or desert vegetation in North America.
The present deserts of the American Southwest owe their origin to increasing aridity in late Pliocene and Pleistocene times, and thus, compared to the forests, are a recent phenomena.
The species, and often the genera in them, are new....” c15

Next, monstrous creatures of ice began to gather on the edges of the forests --
Soon, however, things began to change rapidly.
For some reason (there are many theories), the snow that fell in winter in the north and in the mountains did not all melt the following summer.
Every year there was more carry-over of old snow to the new winter, when even more snow fell.
The winter snowfall increased, and permanent snowbanks in the mountains got larger and became more abundant.
These snowbanks gradually turned to ice and because of their weight began to move down and away from the zone of accumulation.
These events were the beginning of the Ice Age of the Pleistocene Epoch.

Four times the continental glaciers moved down past the middle of the Rocky Mountains... .
Heavy precipitation built up great lakes in what had been the deserts and grasslands of Utah and Nevada.
The western glaciers carved the mountains into new forms; the Tetons, the Beartooth, the Lewis Range, and many others emerged sharp, polished and devoid of much vegetation.
In the eastern half of the continent, the ice stood a mile deep over Michigan and New York, and the Arcto-Tertiary forest was wiped out except in its Southern Appalachian and Mexican refuges.

...The climatic changes of the late Tertiary eradicated or restricted the Arcto-Tertiary and Madro-Tertiary vegetations of the West and aided the evolution of the floras of the present deserts, chaparral, and pine forests.
However, the eastern part of the forest probably escaped serious disruption until the Pleistocene ice.
Nothing was more destructive than the physical mass of ice and the severe climate to the south of the ice front.

The land of the northeastern quarter of the United States and all of eastern Canada was either scoured away or covered with glacial debris; the vegetation was destroyed.
On a major scale, this destruction has occurred four times in the last million years.
After each advance of the ice, warmer periods have followed, the ice has receded into the Arctic and the higher mountains, and the flora has migrated species by species both northward and upward....
All evidence appears to indicate that we are in another interglacial period. c16

Indeed, it is our hypothesis that it has been the human contribution of CO2 return to Earths atmosphere that has forestalled the — now long overdue — ending of the current interglacial, an ending that would be heralded by renewed, gargantuan global drought and desertification, followed by the return of Ice Age conditions, at the timing appointed by the insolation-based and now-coinciding cooling effects of the three types of Earth orbital variations which constitute the Milankovitch mechanism of Ice Age pace-making. 

We believe, that is, that it has been the human CO2 contribution that averted the progression of the ~400 year so-called Little Ice Age, from ~1450 through ~1850, into the next Big Ice Age, so far

However, our hypothesis also holds that this so far inadvertent, unconscious, 'undeliberate', and 'undesigned' intervention of humanitys global Warming Effect will prove insufficient, over time, to hold back the growing, glaciation-forcing momentum of the Milankovitch drivers, all three of which now mutually-reinforce to impend Earths climate in the direction of the termination of the present ~10,000+ year interglacial, and the return of another ~100,000+ years of The Great Ice. 

A conscious, deliberate, and designed human intervention will be necessary, to pace humanitys counter-action — to avoid either under-warming or over-warming in the short-term — if humanitys salvation of the biosphere is to continue much longer in a geologic sense, and if that salvatory contribution is to finally succeed in ending Ice Age 'eco-suicide' by the pre-human/exo-human planetary biosphere of planet Earth p2

Failing such deliberative intervention by humanity, the blind-running destiny of our planet, biosphere and noosphere alike, is the global graveyard of a Snowball Earth. p3


In the foregoing record, we have before us a vast pattern of devastation and decline of the biomass self-productivity of the biosphere, proceeding with accelerating ferocity over a protracted duration of geologic time:  at least the last 22 million years. 

What was the cause of this decline? 

A little further on, we will present evidence that all this devastation was, in fact, a self-devastation of the biosphere, a manifestation of what Marx might have called the internally self-ravaged ground of the evolving planetary ecosystem; that this colossal violence, geologic in scale, was the explosion of the self-contradiction inherent in a photosynthetically-grounded biosphere.

Prior to that, however, let us put in place a few observations regarding the foregoing material. 

We see, within and leading up to this pattern of self-devastation, a prolonged trajectory of decay, a movement of dense jungle giving way to temperate forest, thence to grassland, and finally to desert, barren tundra, and ice; a movement, thus, toward the denudation of the continental land surfaces -- toward the scraping clean of the film of biotic matter from the underlying lithosphere upon which it had grown up. 

It is important to notice the implications of this trend in terms of the pulse-beat of the photosynthetic biosphere, the rate of photosynthesis, the rate of biomass 'self-reproductivity'. 

Even today, under conditions of extreme CO2 rarefaction, and of a world climate unusually cool and dry, the tropical rainforests are much lusher, denser biomes, much more ecologically prosperous regions of the biosphere, more productive in biomass terms, than the temperate forests, not to mention grasslands and deserts [including under this concept tundras and ice deserts]. 

Current estimates indicate that tropical forests exceed other forests by a factor ranging from about 2 to 3 times in Net Primary Productivity [NPP], and exceed the NPP of temperate grasslands by a factor of 4 or greater. c17 

Thus, this movement of succession represents the decadence of the photosynthetic regime; a prolonged secular fall in the rate of reproduction of the biosphere — what might be called contracted natur(e)-al reproduction [or self-contracting ecological self-reproduction].

Much about Nature that we today accept without question as ineluctable facts of life unchangeable as the weather, as the saying goes, had its origin in the protracted catastrophe of global cooling -- and in global-cooling-caused drought, deserticiation, and, ultimately, Ice Age glaciation -- narrated above. 

The descent into cold has profoundly reshaped the climatic morphology of our planet, generating a new global differentiation in both spatial and temporal dimensions. 

Before this climatic cataclysm, neither latitudinal zonation nor seasonal variation were so pronounced as today. 

Instead, a unified global climate prevailed, with a single season year round and a single, tropical zone, virtually from pole to pole. 

The three-way geographical mitosis into tropical, temperate, and polar bands c18; the two-way (in tropics and poles) or four-way (in the two temperate zones) temporal mitosis into dry and rainy seasons, or Fall, Winter, Spring, and Summer seasons c19, are, respectively, both products of the geologically recent period of global cooling — of drought, desertification and glaciation. 

We can at present only speculate about the possible effects of the fantastic loads impressed upon the Earths crust by up to mile-thick jackets of ice, and the resulting depressions and compressions, beginning in the two polar circles, in stimulating associated periods of vulcanism, earthquake, and orogeny (mountain-building) elsewhere on the surface of the planet. c20 [For example, perhaps the pressure of mounting ice-packs literally squeezes magma up out through the volcanic pores of the Earth].

At any rate, it seems clear that the cooling, and subsequent desertifications and ice invasions, as well as the prior warm eras, were not mere local events, but reflected a global process with presumably a global causation --

At present there is little doubt that all the phenomena of the Quaternary glaciation happened simultaneously all over the surface of the globe... .
The ice ages reflected a general decrease of the average temperature of the earth...
...the climate changes took place simultaneously all over the surface of the earth and were not produced by local conditions.c21

Moreover, this epoch of the great global cooling, and great global dying, in which we find ourselves still situated today, represents not a sudden change, but a longterm trend in the climatic evolution [or 'dis-evolution'] of the planet, characterizing not just the Pleistocene Epoch or even the whole Quaternary Period, but at least the entire Cenozoic Era to date --

The most significant feature of the Cenozoic migration of vegetation is the steady retreat of the temperate forest flora from the Arctic regions and the concomitant retraction of the early Tertiary tropical elements of mid-latitude floras into the present marginal tropics.
The curve of floristic change may therefore be translated into a curve of climatic change.
If this interpretation is accepted, it appears that the great trend of Cenozoic climate which culminated in Pleistocene glaciation began in the mid-Tertiary, probably more than 20 million years ago.
Pleistocene glaciation itself, of which present climate is in many respects an extension, may then be regarded as a geologic and climatologic event the antecedents of which extend over a fair segment of recent geologic time and is not to be viewed as a sudden change in the history of the earths climate.c22

We must also avoid, therefore, the empiricist error of assuming the normality or 'naturality' of presently prevailing climatic and ecological conditions -- is apparent that the present climate of earth is not a logical point of departure for interpreting past ecologic conditions of the present land surfaces.c23

Post-Pleistocene humanity, it appears, was born, not into an idyllic, harmonious, balanced, cyclically self-maintaining state of Nature, but into the ruins of a mediately self-ravaged biosphere; into the desolation wrought by a state of internecine ecological warfare within Nature!

What was the source of these vast ecological and climatic movements? 

Strange as it may sound, we are going to argue that the vast forests themselves, together with their marine counterparts, caused their own demise; that their own nature-al’ doing was also their own undoing. 

The glacieral juggernaut which mowed down the ranks of trees; the flood-tide of white which overwhelmed the once-dominant intercontinental carpets of forest green, was a self-reflexion of the forest itself, the other side of its ascendancy, the rebound of its pre-eminence, the mirror image of its burgeoning growth. 

The real domination of photosynthesis is the harbinger of the end of that photosynthesis-domination.

We propose that the well-known hypothesis of the atmospheric greenhouse effect of carbon dioxide is the key to understanding this whole dynamic of the biosphere since the Carboniferous:

“... the carbon dioxide theory is not new; the basic idea was first precisely stated in 1861 by the noted British physicist John Tyndall.
He attributed climatic temperature changes to variations in the amount of carbon dioxide in the atmosphere.
According to the theory, carbon dioxide controls temperature because the carbon dioxide molecules in air absorb infrared radiation.
The carbon dioxide and other gases in the atmosphere are virtually transparent to the visible radiation that delivers the suns energy to earth.
But the earth, in turn, re-radiates much of the energy in the invisible infrared region of the spectrum.
This radiation is most intense at wavelengths very close to the principal absorption band (13 to 17 microns) of the carbon dioxide spectrum.
When the carbon dioxide concentration is sufficiently high, even its weaker absorption bands become effective, and a greater amount of infrared radiation is absorbed [MM-- see Graphics 12a, 12b, 12c reproduced here from this article].
Because the carbon dioxide blanket prevents its escape into space, the trapped radiation warms up the atmosphere... .
Water vapor and ozone, as well as carbon dioxide, have this effect because they too absorb energy in the infrared region.
But the climatic effects due to carbon dioxide are almost entirely independent of the amount of these other two gases.  For the most part their absorption bands occur in different regions of the spectrum.
In addition, nearly all water vapor remains close to the ground, while carbon dioxide diffuses more evenly through the atmosphere.
Thus throughout most of the atmosphere carbon dioxide is the main factor determining changes in radiation flux.
The 2.3 × 1012 [2,300 billion] tons of carbon dioxide in the earths atmosphere constitute some 0.03 per cent of its total mass.c24

Thus, the geologically rapid depletion of CO2 -- atmospheric carbon — by the fabulous rates of photosynthesis of the global forest and its associated oceanic plant forms in the heyday of photosynthesis; the fixation of this carbon in atmospherically inaccessible forms, encased in the corpses of these plants, and of the animals supported by those plants, shielded from normal decay by the very rapidity of their accumulation, and therefore later transformed into 'hydrocarbonaceous' forms, such as coal [on land] and petroleum [in the sea] c25, would have led to a gradual cooling of the global climate which, coupled with the slow suffocation of photosynthesis owing to the progressive CO2 rarefaction of the air, would have paved the way for desertification and the icing of the poles, followed by the extension equator-ward of the polar ice caps, the process known as an Ice Age.

Infrared Absorbers

Graphic 12: infrared absorption
Infrared absorbers in the Earths atmosphere include carbon dioxide, water vapor, and ozone. Spectral charts of their absorption in the infrared region show that these gases warm the Earth by preventing its infrared radiation from escaping into space. Carbon dioxide influences climate because it has a broad absorption band at wavelengths (13-17 microns) near the wavelengths at which the Earths infrared radiation is most intense. Water vapor and ozone can also influence climate.

The causation of the Ice Ages is one of the great, not-yet-fully-solved problems of modern science, and an intensely active area of current scientific speculation and research, as a glance at the contents-page of virtually any recent number of any prominent scientific journal will attest. 

Most of this activity is focused on possible astronomical explanations for the Ice Age phenomenon, i.e., on a causation external to even the geological, let alone the biological, processes of the planet itself.  

Theories of such internal causation are neglected, and/or disparaged.


Another of the great unsolved problems of the Earth Sciences, and of paleoecology, is that of the extinction of the dinosaurs, the rather sudden and thorough killing off of the whole spectrum of plant and animal forms which constituted the Era of the Great Reptiles. 

Here too, we find a very active current literature in the journals, and here also externalist, astronomical explanations, which project the causation of this ecological catastrophe wholly outside the ecosystem itself, are much in vogue. though at least partially-dissenting theories are also lately on the rise.


However, declining temperatures, climaxing the Cretaceous, have long been recognized as a possible cause of, or contributor to, this Great Dinosaur Dying” --

Why did the great dinosaurs die?
It had long been thought that the 150 million year reign of these reptiles on earth was brought to an end by cooling of the earths climate about 65 million years ago.
This idea was supported by geology, but the evidence was incomplete.
At Ureys suggestion, Epstein and Heinz Lowenstam set out to survey the climate of the latter portion of the Age of Reptiles, formally designated as the Upper Cretaceous [MM -- using a new technique developed by Urey in 1950]... their results showed that temperatures rose during the first half of the period and declined during the second half [MM -- see Graphics 14a and 14b below, reproduced here from the text].
Unfortunately they could not measure temperatures at the very end of the period, because they could not obtain suitable fossils.
The study nonetheless supports the conclusion that a decline in temperature might well have played an important part in the extinction of the dinosaurs. c26

The Dinosaurs, mostly lacking anything equivalent or superior to the homeostatic, cybernetic systems of internal temperature and general metabolic regulation characterizing the mammals, which succeeded them, and dependent on climate-sensitive plant life for their subsistence, are thought to have been highly vulnerable to the stresses of falling temperatures and changing vegetation patterns.

Temperatures fluctuated toward the end of the Age of Reptiles. A maximum was reached about 80 million years ago; the subsequent decline may have brought about the extinction of the dinosaurs. Above the graph are two dinosaurs and a primitive mammal.

Temperatures declined during the Age of mammals. Oxygen isotope temperatures (dots) show that Pacific bottom water originating around Anarctica dropped from 10oC to 2oC between 31 and 1 million years ago.  At top are three distinct mammals.

Our hypothesis is that it was the interacting combination of both "external causes" and/with 'internal causes' -- and, in particular, of external, 'exolithic' bombardment of the Earth, and of the [partly-]external, Milankovitch orbital/insolation variation drivers involving Earth's revolutions with respect to the Sun, and/with the Earth-internal depletion of atmospheric carbon dioxide levels, lowering of atmospheric temperatures, and general "drying out" of the atmosphere's water-vapor content, due to the effect of lower atmospheric temperatures in cooling oceanic and fresh water surfaces alike, thus slowing the rate of evaporation of water into the atmosphere, these later effects produced by the photosynthetic biosphere itself -- that induced both the Pleistocene Ice Ages, and the dinosaur demise.



Part 3 --  The Decadence of the Pleistocene Biosphere [Second Part].


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