The World As It Was

Imagine a world of green, ferns and evergreens, from shrubs to trees that tower into the sky like redwoods. The conifer forests stretch on as far as the eye can see. A river lazily meanders through the fields. The climate is warm, but comfortable.

Everywhere you look animal life flourishes and fills the land with abundance. The air is filled with dragonflies and the ground crawls with beetles, centipedes, spiders and scorpions, some much larger than anything we see today.



Images of late Permian animals from wikimedia commons

Even more amazing are the amphibians and reptiles. They are everywhere and range in size from tiny scampering lizards to vast herds of Hummer size giants grazing on the greenery. Smaller plant eaters scamper here and there, disappearing into burrows and popping up elsewhere. Even more amazing are the predators – think giant hairless reptilian werewolves with saber teeth – some reaching almost fifteen feet long. It seems that everywhere you look there are more new plants and animals. The world is bursting with diversity of flora and fauna.

We have travelled back in time, 252 million years to the last days of the Permian period. At this time plate tectonics have gathered together all the continents of earth into on giant landmass, a supercontinent called Pangaea.



Map of the earth at the end of the Permian period 250 million years ago.

We must now visit the oceans, where life itself began. All of the world’s oceans have been combined into an ocean of unbelievable proportions: Panthalassa. Spanning three quarters of the globe, it contains uncharted depths. This ocean is a mystery; we do not know what life prowled its waters. The imagination fills with images of massive sea serpents and alien squid.

A very slow conveyer belt of hot and cold currents carry nourishing oxygen into the deepest trenches before the oxygen depleted waters return the surface where gas exchanges take place that replenish the oxygen and life goes on. Unlike modern oceans, these oceans are stratified with layers of warm water remaining mostly at the surface and cold water sinking to the depths. The deepest, oxygen poor parts of Panthalassa are the home and breeding ground to bacteria that consume sulfur to produce energy and do not need oxygen to survive.

There is also a vast but shallow sea almost surrounded by Pangaea – the Tethys Sea. Plunge into this sea and discover a massive reef system that rivals the complexity of any system today. Trilobites crawl through the waters as alien looking crabs, clams, corals and sponges cover every available square inch of space. Fish dart in and out of the safety of the corals and sharks patrol the open waters. Ammonites, secure in their spiral shells hunt with probing tentacles.



End Permian sea life.

Like the modern world, the ecosphere of the Permian is complete. The same webs of interdependence between plant and animal, between predator and prey that we observe today existed then. This mature, complex ecosystem thrived and prospered just like ours.

But as these plants and animals lived out their lives, volcanoes in Siberia spewed out massive amounts of CO2 into the atmosphere. These volcanic eruptions set off a chain reaction that almost ended complex life on earth.

Aftermath on land

Let us move one million years forward in time; to 251 million years ago and visit those same forests and plains we stood upon.





Stretching in all directions, as far as the eye can see is barren land, sandy here, rocky there. Not a trace of green remains, no plants live here. Nothing remains of the forests we saw, not even rotted tree trunks. Plants cannot survive here.

Where the river had meandered there are dried, braided stream beds partially filled with sand. Sometimes there are massive dust storms of catastrophic intensity and duration, but rock and sand remain to see them.

The merciless sun bakes the ground in temperatures reaching daytime highs of up to 154ºF (.pdf warning). In places the ground is cracked and buckled, parched beyond all recognition. There is no rain here, ever. Decades pass without even the smallest amount of moisture intruding.

The air reeks with a bitterly pungent mixture of sulfur and methane. But worse than that, little oxygen is present. Here at sea level is equivalent to standing on top of a 5.3 kilometer tall mountain – 17,000 feet high (.pdf warning) – in today’s world. A human here might die rapidly from high altitude pulmonary edema or high altitude cerebral edema.

Welcome to the world of runaway global warming.

The aftermath in the waters

From the surface, the oceans look deceptively normal. The tidal action of the moon stirs the surface. But plunge beneath and the truth is revealed. There is nothing alive. The massive ocean that encompasses 75% of the entire world is dead. No plankton, no fish, no jellyfish, no recognizable life at all. There remain only trillions upon trillions of gallons of apparently lifeless water. Even the algaes that produced the majority of oxygen for the world have died.

The surface water is much warmer than before but just below this surface layer lays an unfathomed icy crypt of darkness. There are no currents. The conveyer belt that brought cold water down to the depths has broken and apart from the very surface of the ocean, there is no oxygen.

Despite appearances, life continues. The anaerobic bacteria do not need oxygen to thrive. They have fed upon the countless corpses of marine organisms who drowned in anoxic water. Now the bacteria use inorganic sources of energy to feed and reproduce. Others use the energy of the sun to feed themselves.



Cyanobacterial mats

In some places the surface of the ocean is coated by tens of thousands of square miles of cyanobacterial mats – slime algae. Primitive, single celled organisms are the only life in this ocean. As these organisms thrive and reproduce they release Hydrogen sulfide (H2S) as a byproduct of their metabolism – and hydrogen sulfide poisons organisms that require oxygen, both plants and animals. The waters grow more inhospitable to complex life with each passing year.

Reentering the Tethys Sea is we discover much lies buried under layer after layer of monotonous bacterial mats. Mile upon mile of once beautiful thriving reef is lifeless...



Scenes of mass death of marine life as a result of the anoxic zone off the Oregon coast; the fish, crabs and starfish washed on shore and were photographed there.

The reef structures themselves are largely gone. As the CO2 levels in the oceans increased, the pH of the oceans dropped - CO2 is acidic. Once the pH levels dropped low enough the reef building organisms were no longer able to use calcium carbonate to make shells or reef structures. Crabs, clams, oysters, corals all suffered. The existing structures began to erode as the acidic waters eroded their very components away.



Dead, bleached coral reef in the Caribbean

How and why complex life almost vanished from the earth

This is the Permian – Triassic (P – Tr) extinction; the largest mass extinction known in the history of the earth. On land up to 80% of all living organism died; entire biological families vanished. Even insect populations, spared by all other mass extinctions, have taken a brutal hit. But land dwelling animals and plants fared much better than their marine counterparts. In the ocean over 90 to 95% of all life died.

Scientists call it the Great Dying and for one brief moment it looked as though all multicellular life might be extinguished.

While there are competing theories out there (including the ever popular massive asteroid impact) scientific consensus centers on global warming as the culprit in the almost successful eradication of complex life.



A graphic illustration of the loss of diversity: the Permian ocean life before the mass extinction - then after.

Very late in the Permian massive – truly massive volcanic eruptions took place. These eruptions in the Siberian Traps lasted around 700,000 years and poured CO2 and other gases into the atmosphere. It is likely that during this time there were periods of global cooling – caused by the ash in the atmosphere reflecting the sunlight. But overall, CO2 levels, much as they are today, trapped heat in the atmosphere, gradually raising global temperatures.

At some point the global temperature increase reached a critical level and methane clathrates (methane hydrates) stored in the ocean were released. A methane clathrate is essentially a methane molecule trapped inside a cage of water molecules by a combination of low temperatures and high pressures. If the temperature of the water surrounding the methane increases past a certain level, the methane is released. It appears that the modern ocean floor contains significant amounts (millions of gigatons) of methane hydrate and this would likely have been true in the past.



A clathrate releases bubbles of methane gas

Methane (CH4), like CO2, is a greenhouse gas – it traps heat in the atmosphere. But Methane is at least 20x more powerful than CO2 as a greenhouse gas. Once methane clathrates began to destabilize the atmospheric heating increased which in turn destabilized more clathrates and on and on. The massive release of methane caused a rapid, sharp spike in global temperatures.

The Permian oceans (the Tethys Sea and the Panthalassic Ocean) started at a warmer temperature than our oceans today (.pdf warning). Thus, rather than the conveyer belt system we have today where cold, highly saline water near Greenland and Antarctica takes in massive amounts of oxygen and then sinks and keeps the conveyer belt in rotation, a much weaker circulation system existed in the Permian. There were few glaciers to create the cold, saline water and the oceans started out stratified with high oxygen levels near the surface and low oxygen levels below.

Oxygen is consumed as part of the decomposition of organic. As plants and animals die due to increased temperatures and lack of oxygen, their bodies decay which further depletes the oxygen poor waters until the only organisms left are single celled bacteria which consume sulfur compounds and produce hydrogen sulfide – which is lethal to organisms that breathe oxygen.

The hydrogen sulfide levels in the ocean increase rapidly and rise to the surface, killing off the marine organisms still surviving. This includes algaes that produced the majority of the oxygen for the planet. Above the water, oxygen levels worldwide begin to plummet. Hydrogen sulfide levels increase. The increasing temperatures worldwide begin to kill off terrestrial plant life. As the deserts of central Pangaea expand, less and less and less plant life is left.





Land animals begin to die as well. Many species can no longer exist near the equator. The increased temperatures, the lack of vegetation and water drive them to higher latitudes –but not higher altitudes. In fact, animals which previously thrived in the low oxygen high altitude environments have moved to low altitudes where the oxygen concentration now resembles what used to only be found in mountaintops. The low altitude animals, adapted to a high oxygen environment, die.

Some scientists estimate that this process took only 80,000 years from start to finish. This was not a steady rate of death; there were pulses where more death occurred than at other times. However, current evidence suggests that virtually all the marine deaths happened in one amazingly brief moment in geologic time.

The Recovery

We are here today so obviously complex life survived. But the recovery was a long and tenuous process. During other mass extinctions it appears that plant and animal life rebounded fairly rapidly, often in less than a million years. The Permian – Triassic extinction took five times that long.

Some researchers think that it took as long as one hundred million years for the planet to reach its previous oxygen levels. This had a direct effect upon the course of terrestrial life on the planet. The reptiles that were flourishing just before the Permian extinction were called “mammal-like reptiles.” Biologically similar to modern mammals some may even have had fur. These animals almost disappeared during the Permian extinction; lucky for us a few survived.

Another reptile family did pretty well after the Permian extinction. The diapsid reptiles took control of land and sea. Their descendants include the dinosaurs. Recent fossil discoveries indicate that dinosaurs may have had complex lungs – similar to their descendants, the birds. Did the dinosaurs achieve domination of the earth because their lungs were more efficient than our ancestors?

Can it happen again?

It is important to note that there are massive differences between the world today and the world of the Permian – Triassic extinction. Our landmasses are split into seven continents, not one giant one. We have several distinct oceans, each with their own currents and conveyor belts. We don’t have the problem of massive volcanic activity. Our base temperature is lower than it was in the Permian; we have polar ice caps which did not exist at that time.

Another factor is the distorted and incomplete picture from peering backwards into time – the gaps in the evidence, the risks if misinterpreting the data that does exist. There is persuasive supporting evidence for this theory but there are also gaps and inconsistencies. That’s the nature of science when you peer this far back into the past.

But there is no reason to think that the biosphere of earth has changed so fundamentally that the events of the Permian extinction could not be repeated. The atmosphere does not care if the atmospheric carbon which causes the warming comes from volcanoes or coal fired power plants. One hundred million cars and trucks on the roads for ten years might have the same effect as a Vesuvius on global warming. The rules still apply.

Disturbing similarities exist between our world and the end Permian:

• Our biological systems are stressed – worldwide ecosystems everywhere are suffering. Many scientists believe we are already in the midst of a mass extinction.

• Atmospheric CO2 levels are steadily increasing, as are global temperatures.

• Weather systems and patterns are changing; adding additional environmental stress to already strained ecological chains.

• The arctic is warming dramatically. This weakens the Atlantic Ocean conveyor belt which oxygenates our oceans.

• Methane is leaching out of the defrosting permafrost.

• It is estimated that at least 50 gigatons of methane under the Arctic Ocean can potentially be released at any time – enough to almost immediately double the carbon levels in the atmosphere.

It is unlikely but not unthinkable that we – human beings – can literally precipitate a mass extinction which would result in the death of all multicellular life on earth, leaving the planet where it was 2 billion years ago: a rock covered with stagnant water, populated by mats of slime.

Or we can take action against global climate change. The choice is ours to make.



Map of locations of methane clathrates.

If you want to take action, this is where I would start:

350.org

also check out:

Get Energy Smart Now!

and

Green Options

SOURCES

Hypoxia, global warming, and terrestrial Late Permian extinctions, RB Huey, PD Ward - Science, 2005

Climate Simulation of the latest Permian: Implications for Mass Extinction, Kiehl, J.T., Shields, C.A. Geology; September 2005; v. 33; no. 9; p. 757–760

Non peer reviewed sources:

Gorgon: The Monsters That Ruled the Planet Before Dinosaurs and How They Died in the Greatest Catastrophe in Earth's History by Peter Ward (This is a link to the Amazon page; this a a book and is not online)

Climate Model Links Warmer Temperatures to Permian Extinction

Researchers Warn Of A Methane Clathrate Destabilization Time Bomb Due To Global Warming

Methane Bubbling Up From Undersea Permafrost?

Boost to CO2 Mass Extinction Idea

Recovering from a Mass Extinction

Canada's Shores Saved Animals From Devastating Climate Change 252 Million Years Ago

Global Warming Led To Atmospheric Hydrogen Sulfide And Permian Extinction

When Bivalves Ruled The World

The Permian Extinction—When Life Nearly Came to an End

The Day The Earth Nearly Died

The Great Dying