This is the transcript for the video
"How CO2 Starvation & Plate Tectonics Caused the Greatest Mass Extinction, the Permian Great Dying"
Welcome back everyone.
This video will explore the wealth of evidence suggesting that the combination of CO2 starvation and plate tectonics caused the greatest extinctions on earth collectively known as the end Permian extinction or the Great Dying.
The end-Permian marked the transition from 300 million years of Paleozoic plant and animal dominance and the resetting of earth's evolutionary trajectory, towards our modern fauna.
The Permian extinctions represented a loss of 57% of all biological families, 83% of all genera, 81%of marine species and 70% of terrestrial vertebrate species in existence in the end Permian’s last million years.
Coinciding with these Permian extinctions was the decline of abundant CO2 concentrations since the Ordovician period to the stressful low concentrations in the Permian.
For the first time in earth's history, CO2 concentrations fell below 1000 ppm, the concentration that supports maximum photosynthesis productivity.
While plants suffered from low CO2, land vertebrate extinctions were largely a result of oxygen's dramatic roller coaster ride that crashed in the Permian.
It is essential to first understand how changes in CO2 concentrations affect photosynthesis and plant productivity.
The key productivity enzyme, Rubisco, grabs a CO2 molecule and then shuttles it down a metabolic pathway to produce the sugars and carbohydrates essential for all life.
Today various versions of Rubisco are saturated when CO2 reaches 1000 ppm thus maximizing photosynthetic production.
Our current atmospheric concentrations are only 40% of the optimum. For that reason, modern commercial greenhouses raise CO2 to 1000 ppm for maximum crop yields.
During pre-industrial times of the Little Ice Age, CO2 concentrations fell to 280 ppm and evidence shows during that time ocean productivity was much lower than today.
If CO2 concentrations fall below 150 ppm, then photosynthesis can stop completely. So, policies to sequester and lower CO2 must be very careful not to approach this deadly level.
There are many competing theories regards the causes of the massive Permian extinctions, but scientists are nowhere near a consensus.
Click-bait media such as the NY Times have been obsessed only with theories blaming warming temperatures. They then segue those theories into fearful narratives about extinction threats from modern global warming.
However, many researchers have pointed to the competition for the declining CO2, that resulted in severely reduced photosynthesis, the collapse of primary productivity and a significant malfunction of the global food webs. Evidence is rapidly accumulating to support their conclusions.
During the Ordovician with CO2 concentrations 5 times greater than the saturation level, newly evolving photosynthesizing species were not limited by competition for CO2. Thus, the greatest phytoplankton diversity developed then.
By the Permian, CO2 concentrations fell to a stressfully low 200 ppm and very few new species appeared.
There is a strong correlation with origination of new Paleozoic phytoplankton species (illustrated in green) and the concentration of CO2 (seen on the right).
During the great Ordovician Biodiversification Event, the greatest abundance of newly evolved phytoplankton species correlated with high CO2 concentrations. New species typically also suffer higher extinction rates (illustrated in red) as they evolved to survive in niches that are still in flux.
As CO2 concentrations plummeted during the Devonian when land plants competed for and sequestered more CO2, fewer new marine phytoplankton species evolved, and extinctions increased.
By the end Carboniferous and early Permian periods, virtually no new species appeared as CO2 concentrations fell dangerously close to levels at which photosynthesis could no longer be supported.
As a result, much of the green algae clades that had dominated the Paleozoic oceans died off, although this clade also provided the ancestors for land plants.
Phytoplankton from the red clades with more efficient photosynthesis, rose to dominance later in the age of dinosaurs and still dominate ocean primary productivity today.
When CO2 concentrations reached their lowest levels ever in the early Permian, phytoplankton fossils became extremely rare and the Permian experienced what scientists call a "phytoplankton blackout."
So why the Permian blackout?
Biased by the last mass extinction event at the end of the cretaceous when the earth was struck by an asteroid, researchers often search for a single devastating event, like an asteroid or a massive volcanic eruption to explain what happened during the end Permian. However, there is a growing scientific belief that the Permian extinctions were more gradual and caused by a protracted decline in environmental conditions that slowly reduced the earth's biodiversity and thus reduced the probability of new species evolving that can adapt to changing conditions.
This notion of a protracted extinction was discussed in the 2021 paper "dead clades walking". A clade is a group of organisms that evolved from a common ancestor. Multiple minor extinction events can gradually reduce a clade’s biodiversity and its resilience, so that the clade is doomed to extinction several million years later.
Clearly a mass extinction does not require an asteroid. The gradual reduction in phytoplankton and photosynthesis can collapse food webs and result in major extinctions that, in the sparse fossil record, are incorrectly interpreted as a relatively rapid extinction event.
The media likes to emphasize the earth's 5 great mass extinctions. But several previous minor extinctions have all contributed to dead clades walking, clades that finally went extinct during the Permian mass extinction.
The first so-called great mass extinction happened during the Ordovician just after the great biodiversity event. Associated with the Ordovician icehouse, 61% of marine life disappeared and mostly culled many of the new species that had recently evolved in a previous warmer climate.
The late Devonian mass extinction was more disruptive, involving the loss of entire carbonate reef ecosystems that had dominated the early Paleozoic oceans. However, many researchers now believe that the end Devonian extinctions were simply the last of up to 7 protracted minor extinction events during a time when the colonization of the continents by land plants was rapidly depleting CO2 concentrations and dramatically reducing phytoplankton biodiversity.
The beginning of another glacial period during the mid-carboniferous caused 14-39% of the marine genera to go extinct.
The carboniferous rainforest collapse driven by drying continents and extremely low CO2 concentrations is considered to be only a minor extinction event, yet it totally altered tropical ecosystems and marked the peak in atmospheric oxygen before oxygen plummeted during the Permian.
Between 7 and 17 million years before the end Permian mass extinction, between 35 & 47% of marine invertebrate genera went extinct as well as nearly 80% of land vertebrates.
Those previous extinction events reduced biodiversity and support beliefs that the end per main mass extinction event was likely the culmination of dead clades walking.
The end Triassic and end cretaceous mass extinctions are the last two of the great extinctions but will not be examined here.
By sequestering CO2 and raising oxygen concentrations, photosynthesis paved the way for its own demise by amplifying photorespiration which greatly reduces photosynthesis in both marine and land plants.
The key enzyme Rubisco first evolved when CO2 was abundant and oxygen scarce. Thus, under those conditions Rubisco could be sloppy about discriminating between CO2 and oxygen yet still be productive.
As oxygen concentrations increased and CO2 decreased throughout the Paleozoic, Rubisco increasingly grabbed oxygen instead of CO2 initiating destructive photorespiration that reduces plant productivity.
Laboratory experiments under current oxygen levels found when CO2 concentrations are as low as 220 ppm, plant biomass production is reduced by 50% and 30% of that reduced productivity was due to photorespiration. When CO2 was reduced to 150 ppm, productivity was reduced by 92%.
For ocean phytoplankton, reduced CO2 is even more detrimental. When CO2 diffuses into the ocean most molecules immediately react with water creating 3 forms of inorganic carbon. CO2, bicarbonate, and carbonate ions. (Left graph) bicarbonate ions now constitute over 90% of the ocean's inorganic carbon, but rubisco can only use CO2 molecules.
Furthermore, as CO2 is depleted ocean pH rises (seen in right graph). And ocean pH controls how the inorganic carbon is proportioned between more useable CO2 and bicarbonate ions.
When CO2 falls to 200 ppm, ocean pH rises to 8.5 and the amount of available CO2 approaches zero.
To survive the negative effects of reduced CO2, phytoplankton have evolved CO2 concentrating mechanisms that increase the internal CO2 concentration.
Photosynthesizing cyanobacteria evolved the ability to import bicarbonate ions and shuttle them into a carboxysome where an enzyme converts bicarbonate ions into CO2 while in the proximity of Rubisco.
Algae evolved similar mechanisms with pyrenoids. Without a carbon concentrating mechanism, Paleozoic phytoplankton species experienced limited growth.
All modern phytoplankton have developed various CO2 concentrating mechanisms to survive in today's low CO2 world.
Experimental phytoplankton strains with dysfunctional CO2 concentrating mechanism just cannot survive.
As CO2 has declined over the last 20 million years several clades of land plants (yet still a small percentage of all species) have evolved a similar CO2 concentrating mechanism known as c4 photosynthesis.
In the upper sunlit euphotic zone, phytoplankton generate an abundance of dissolved organic matter and sinking particulate matter.
That organic matter sustains an abundance of marine life in the complex food webs of the dark twilight zone.
Today's oceans contain as much dissolved organic matter as exists in the earth's terrestrial ecosystems.
Several scientists had questioned the reliability of the phytoplankton blackout data because robust invertebrate communities persisted in the fossil record for longer times despite crashes in phytoplankton species.
However, awareness of the bacterial loop, first published in 1983, has altered scientific thinking about ocean food webs. Before 1983, it was widely believed that only phytoplankton could directly sustain the zooplankton, and benthic animals.
However, it is now understood that the bacterial loop recycles dissolved organic matter and thus can maintain a substantial food web until the dissolved organic matter is depleted.
However, unlike oxygen generating phytoplankton, the bacterial loop consumes oxygen and expands the oxygen minimum zones which coincide with the many deadly anoxic events of the Permian.
The complex interactions between, disappearing phytoplankton, cyanobacteria and bacterial loops resulted in the extinction of various Permian marine animals in various niches at different times.
Looking more closely at the stages of the Permian, begining with the ending of the Paleozoic ice age there were large losses in biodiversity with major extinctions during the earliest Permian stages.
Ammonoids had been declining for the Permian’s' first 30 million years with many going extinct 17 million years before the end pemican extinction.
By the Capitanian stage, 75% of the Permian coral families became extinct as well as 82% of coral species.
By the end Capitanian stage, 7-10 million years before the end Permian, 35 to 47% of all marine invertebrate genera had gone extinct. Many researchers now include the Capitanian extinctions as one of the earth's 6 great mass extinctions and separate it from the end Permian. The Capitanian extinctions happened in a cool climate and before the rapid rise in CO2 and the warming that some blame for causing the end Permian extinctions.
On land, North American coal deposits disappeared in the early Permian after the carboniferous rainforest collapsed.
Stressful atmospheric CO2 hovered between 150 and 700 ppm during the late carboniferous.
The lowest calculated values of 100 ppm would have been lethal for many Permian plant species and correlates with the disappearance of coal deposits.
Both laboratory experiments and paleontological evidence show most plant species respond to low CO2 concentrations by producing more stomata to increase CO2 diffusion into the plant.
However more stomata increase water loss and make the Permian plants more vulnerable to the increasing dryness throughout Pangea’s formation. As a result, minor plant extinctions happened throughout the Permian, starting with the Carboniferous Tropical Rainforest Collapse.
The towering lycopsid rainforest trees went extinct leaving only related diminutive species requiring less carbon, some of which have survived until today and are frequently used in terrariums.
As moisture requiring species were extirpated and drought tolerant species increased, food chains were gravely disrupted resulting in the mid-Permian Olson extinctions.
By the Roadian stage 45% of the plant species had gone extinct in the Chinese micro-continents. And by the Capitanian 56% had gone extinct.
Declining biodiversity reduces the probability of new species evolving that would otherwise balance out natural background extinctions.
The formation of Pangea had a negative effect on biodiversity. Pangea removed unique niches from its converging island-like micro-continents. Studies of modern island biology have demonstrated how only a few species are genetically capable of producing a radiation of new species, and only when vacant niches are available.
The "oldest" existing volcanic Hawaiian island, Kauai, emerged about 5 million years ago which is about the time of the arrival of the ancestor of Hawaii’s honey creepers. Since then, one ancestor gave rise to at least 12 unique species, each evolving varied beaks to exploit Hawaii’s unique vegetation.
Of the hundreds of continental vagrant species that ever arrived on the Hawaiian Islands, only a few remained and they only evolved small changes in size or color. But even fewer possessed flexible genomes that allowed successful speciation that could exploit unfamiliar but available niches.
Likewise, the ancestor of the Galapagos finches arrived about 2 million years ago on the volcanic islands and radiated into at least 14 unique species.
During the early Paleozoic, in the Ordovician, many of today's continental land masses were just a multitude of separate large volcanic islands or micro-continents. Islands provided more coastlines with unique coastal niches for marine species.
There were also more abundant shallow seas that readily recycled critical nutrients that would otherwise be sequestered in the deeper ocean.
The convergence of those Ordovician micro-continents into the fully united single continent of Pangea during the Permian, reduced coastlines, and the areal extent of shallow seas.
Pangea's formation also provided connectivity that allowed more competitive generalist species to invade and eradicate species living in previously unique niches of isolated islands. The loss of productive shallow seas exterminated the least productive species within those habitats.
And the loss of coastlines reduced the flow of water vapor from the ocean to the inland. As Pangea consolidated, the continental interiors dried and inland species that had adapted to previous wetter climates became the first to go extinct, like the lycopsid trees of the carboniferous rain forest.
However, species on the islands of north and south China persisted for millions of years later.
The drivers and timing of terrestrial vertebrate extinctions often differed from ocean extinctions. However, the ultimate drivers were still CO2 starvation and Pangea’s formation.
As plants colonized the land, global CO2 was further reduced to near lethal levels for algae by the end of the carboniferous, while oxygen levels rapidly increased to the highest levels ever in the earth's history, benefiting greater animal speciation.
The abundance of oxygen enabled an increase in terrestrial biodiversity as the more aquatic species could venture further onto the land and survive as sufficient oxygen simply diffused through their moist skin or via other forms of primitive breathing. The legacy of these early evolutionary experiments is still seen in amphibian and reptile species that survive today.
Lungless salamanders still totally rely on simple diffusion through their skin for uptake of oxygen (orange bars) and removal of CO2 (green bars). Many frogs and salamanders have aquatic larvae that breathe in water with gills, then metamorphose to air breathing adults with moist skin and primitive lungs ventilated by constant throat flutters.
Despite better evolved breathing mechanisms, many reptiles still supplement their oxygen via diffusion through their skin.
However, oxygen concentrations plummeted during the Permian as the phytoplankton blackout, the rainforest collapse, and Pangea’s switch to less productive vegetation in drier conditions, had dramatically reduced the photosynthetic production of oxygen. Different clades of land vertebrates that had recently evolved in a climate of abundant oxygen, could not compete with species that had evolved more efficient breathing.
Insects rely on passive diffusion for breathing. The high oxygen concentrations enabled the evolution of the earth's biggest insects and centipedes during the carboniferous. however, those giant insects were the first to go extinct as oxygen levels plummeted during the Permian. In fact, it was the only time our earth had ever experienced the mass extinction of insect clades.
Because true amphibian and reptiles had not evolved yet, and the varied characteristics of Permian vertebrates often blurred the line between reptile and amphibian, many Permian vertebrates are best referred to as just tetrapods (4- leggeds) or amniotes if they no longer needed to lay their eggs in water.
One clade of amphibian-like animals, the lespospondyls, appeared in the carboniferous but were extinct by the mid Permian.
Another clade of amphibian-like tetrapods also evolved in the carboniferous
And some evolved reptile-like characteristics as well. While some species also went extinct by the mid Permian, others survived into the age of dinosaurs.
Synapsids were reptile-like animals whose surviving species gave rise to mammals.
The pelycosaurs were sysnapsids that dominated the early Permian but went extinct by the mid-Permian.
The dinocephalians were synapsids that replaced the pelycosaurs. But they went extinct by the Permian’s end Capitanian stage.
Diapsid clades replaced the synapsids in the mid-Permian. This clade's more versatile genetics withstood the end-Permian extinctions and enabled the Mesozoic evolution of crocodiles, dinosaurs, birds, snakes, and lizards, many of which have persisted though today.
In light of all the many extinction factors, the NY Times' promotion of only climate warming as the cause of Permian mass extinctions simply to maintain fear regards our current climate warming, is egregiously irresponsible. The serial reduction of biodiversity for most clades from the Ordovician to the end Permian, strongly suggests CO2 starvation was a far more powerful ecosystem disruptor than periodic warming episodes.
The loss of 61% of marine biodiversity during the Ordovician glaciations, not only demonstrates the lethal power of colder temperatures, but also calls into question the role of CO2 as a temperature control knob.
The Ordovician icehouse happened when CO2 concentrations were ten times higher than today at 5000 ppm.
Some scientists argue solar output was 4% lower and thus counteracted any warming from high CO2. But a solar drop of 7 w/m2 of insolation, does not counteract 13.5 w/m2 of calculated greenhouse warming.
The late Paleozoic icehouse has been attributed to falling CO2 concentrations, even though the glaciations were initiated in the early carboniferous when CO2 was about 2000 ppm. Scientists have proposed other theories for glaciations happening under high CO2 concentrations, suggesting the formation of Pangea prevented warm ocean currents from moderating the polar climate of the southern hemisphere.
By cherry-picking the rise in CO2 only during the very end Permian, such blinkered analyses have allowed some researchers to echo the narrative that it was deadly CO2-driven global warming that caused end Permian extinctions and then fearmonger their conclusions to rant we're in danger of extinction from today's 1-degree Celsius warming climate.
However, such theories totally fail to account for dead clades walking and the numerous extinctions that set the stage for the end Permian extinctions via colder conditions and CO2 starvation.
So, I encourage you to heed the warning from Aesop 2500 years ago. We must avoid any remedy that is worse than the disease. Rash attempts to sequester CO2 and lower its concentrations to levels approaching plant starvation, will prove to be disastrous.
Likewise, shun bill gates' "block the sun" proposals. Such lunacy will definitely disrupt the earth's life-giving carbon cycle and upset global productivity and devastate all ecosystems! Scientists must take a closer look at how CO2 starvation caused the world's greatest extinctions and act accordingly. Furthermore, click-bait media needs to be shamed into honestly educating the public about all the science.
Thank you.
For more superb educational climate science Bookmark my YouTube channel https://www.youtube.com/channel/uc7xnhez2qcj_phf2mvdfk0q/videos
Or read the transcripts at perhapsallnatural.blogspot.com
Jim Steele is an ecologist and Director emeritus of San Francisco State University’s Sierra Nevada Field Campus, (whose research restored a critical watershed), author of Landscapes and Cycles: An Environmentalist’s Journey to climate Skepticism, and proud member of the CO2 Coalition.
