In the first Eon called the Hadean (Hades or Hell Eon) (4.6 to 4 byr),
That’s the mainstream picture of our planet's development but I’ve shown how all three of these concepts have major flaws.
I’m pleased to see, Wiki has done some updating on this subject
Study of zircons has found that liquid water must have existed as long ago as 4.404 ± 0.008 Ga, very soon after the formation of Earth. This requires the presence of an atmosphere. The cool early Earth theory covers a range from about 4.4 to 4.0 Ga.
In fact, recent studies of zircons (in the fall of 2008) found in Australian Hadean rock hold minerals that point to the existence of plate tectonics as early as 4 billion years ago. If this holds true, the previous beliefs about the Hadean period are far from correct. That is, rather than a hot, molten surface and atmosphere full of carbon dioxide, Earth's surface would be very much like it is today. The action of plate tectonics traps vast amounts of carbon dioxide, thereby reducing greenhouse effects, and leading to a much cooler surface temperature, and the formation of solid rock, and possibly even life.
In the second Eon called the Archean (4 to 2.5 byr), the earliest life forms were single celled microbial cyanobacteria.
Cyanobacteria used sunlight for digestive energy, ate CO2, kept the carbon to make sugar and pooped out O2 which began to oxygenate the planet.
The O2 readily bonded with iron forming a non soluble rusty magnetite (magnets).
The rusted magnetite sank to the bottom of the ocean floor forming sedimentary red bands.
Zoic = of or relating to animal life.
In the third Eon called the Proterozoic (2.5 byr to 541 myr), multicellular life forms, not complex life but life that reproduces itself primarily by cell division took hold.
This is microbial life.
The earliest forms of plant life develop in this period.
Oxygen levels begin to rise dramatically toward the end of this period.
Oxygen helps power complex lifeforms more efficiently which opened the door for the next Eon.
This brings us to the fourth Eon called the Phanerozoic (542 myr to present).
This is where Earth and life on it become complex, diverse and intimately interconnected as a biosphere, a self regulating closed system. It is estimated that 95% of all life on Earth has gone extinct, the biosphere we live in today is the last 5%.
Life on earth today is the culmination of a succession of changes over a span of five billion years, its the gravitational migration process from a solar cloud of dust and gas to complex and semi intelligent life. We are the pinnacle of this process.
There are 5 mass extinction events that have taken place during the Phanerozoic Eon indicated by the yellow triangles in the image to the right. This view, however, is somewhat misleading.
A mass extinction is when 75% of species die. While the cause of these extinctions is not 100% known, most mass extinctions are believed to occur as the result of rapid climate change.
Extinctions usually take place over very long time periods, (20 to 25 myr). Extinctions, more often than not, are a slow migration process, a succession of failed attempts to survive adverse conditions.
In 1 of the 5 mass extinctions, a rapid catastrophic climate change event took place within a short period. A large meteor hit Earth 66 mya which drove all large animal species extinct.
This chart demonstrates more accurately how extinctions are typically a series of multiple failed survival attempts over time.
Extinctions have taken place continually since life began. These extinctions are only called mass extinctions when overlapping extinctions pile up to equal 75% loss of life.
Comparison of the three episodes of extinction in the Late Devonian (Late D) to other mass extinction events in Earth's history. This chart file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
We are currently in the Quaternary period colder periods within the Quaternary are referred to as glacials while warmer periods are called interglacials but we have been in an ice age for 2.58 myr.
The cyclical pattern of these glacials and interglacials revolves around two basic time frames of 41,000 and 100,000 years. Cold glacials lasted about 100,000 years while warmer interglacials lasted about 10,000 years. In other words temperature tends to rise relatively fast while dropping relatively slowly.
I've combined several charts into one in order to align extinction events with climate change and CO2 levels to better understand exactly how these different factors align.
The vertical red lines that run down the entire image are aligned to the five mass extinction events.
Calling these mass extinctions "events" is pretty misleading as most are not "events" rather they are long periods where life has been beaten into non existence under prolonged adverse conditions.
The meteor impact that took out the dinosaurs was an event that caused mass extinction but all the other extinction periods took place over long time scales.
The great dying event (period) took place 250 mya and 95% of all species went extinct during this period.
The dinosaurs were wiped out at the cretaceous paleogene (KT or K-Pg) boundary 66 myr. Since that time, life has flourished and risen to heights never before seen on Earth.
If a rise in temperature is caused by a rise in CO2 levels then as CO2 increases a directly correlated rise in temperature will also occur.
The time increment of the CO2 chart runs from left to right while the temperature chart below runs from right to left.
The below temperature chart has more detail in it than the one above.
About 20 million years ago India was pushing into China.
This process began building the tallest mountains in the world called the Himalayans.
Raising this much rock high into the atmosphere had a tremendous CO2 scrubbing effect on the atmosphere.
The rock absorbs atmospheric CO2 like a sponge absorbs water.
Vast quantities of CO2 were sucked out of the atmosphere by the Tibetan Plateau.
This caused the Earth to cool steadily away from previous historical norms.
This set up the conditions for rapid cyclical (41kyr, 100kyr) glacial and interglacial periods.
I pulled out a section from both the CO2 and the temperature chart that encompasses 175 myr to 50 myr.
I mirrored the CO2 chart so the graphs run in the same age direction from right to left.
The yellow line in the CO2 graph is the most important, the dark blue line is a 30 myr averaging designed to smooth out the yellow line but it is distracting, focus on the yellow line which is the actual GEOCARB III CO2 calculated levels.
As temperatures were increasing a meteor struck Earth and killed off the dinosaurs at the KT or K-Pg boundary. From 175 to 50 myr, except for the KT boundary biodiversity flourished from and grew on Earth as temperatures climbed and CO2 dropped.
This demonstrates that elevated temperature levels were not, at this time period, created by increasing CO2 levels. Other factors were at play which increased Earth's temperature. Something other than CO2 was responsible for Earth's temperature rise 175 to 50 mya.
When CO2 rises, temperatures follow but CO2 doesn't have to rise in order for temperatures to rise.
Two hundred and fifty million years ago temperatures were near their hottest (10.5 C, 19 F above current norm) and this is when Earth experienced the largest mass extinction, ocean levels were near their lowest but beginning to rise, CO2 levels were around 1,400 ppm
For the past 365 million years until the Neogene period, the high low zone for CO2 ranged from 2,300 ppm to 450 ppm placing its average at 1,375 ppm.
A hundred and sixty million years ago during the Jurassic when CO2 levels were at their highest in 365 myr, temperatures were near their lowest and Earth was in a glacial period.
One thing that's clear from the temperature chart is we've been living in a Goldie Lox period for 12,000 years.
Earth's climate has been far more radical in the past and it is likely because of the diversity of life that our planet's temperature has been so well regulated and moderate.
Life on Earth establishes the conditions to regulate temperatures. If the balance of either is disrupted the other will likely follow.
Ice core samples from the Antarctic at Dome C give us a record of atmospheric CO2 level for the past 800,000 years.