August 25, 2010
History poised to repeat itself
Billions of Years ago
Our Earth is 4.6 billion years of age. It can still exist for 7 billion
Years before the sun becomes a giant star, and utterly destroys it.
The temperature of Earth is determined by the balance between the
Energy it receives from the sun, and the energy it reflects back into space.
Atmospheric carbon dioxide (CO2) is the major determinant of the latter.
The correlation between Earth’s temperature and CO2 is impeccable.
Millions of
Years ago
From 600 to 318 million years ago, atmospheric CO2
was at least 1,000-3,000
Parts per million (ppm), compared to 391 ppm today. In waters long since
Displaced by Western Australia, early life built the flamboyant 120 meter-high,
160 Kilometers-long coral mound, we call the Devonian Canning Barrier Reef.1
From 318 to 299 million years ago, atmospheric CO2 declined to a level lower
Than ours today. Ice formed on the southern end of what was then the
Super-continent of Gondwana. Further north, plants covered the ground,
Providing shelter for invertebrates, these, in turn, choice food for early lizards.2
From 299 to 251 million years ago, CO2 at first continued low, then suddenly
Shot up, causing all ice to melt, and the extinction of 95 percent of all
Species. The peak was followed by a long downward trend which, with
Oscillations, gave us a CO2 level, in 1750 C.E.(pre-industrially), of 280 ppm.3
34 million years ago, a sharp downturn in CO2 level superimposed itself on the
Slow cooling trend. CO2 decreased from 540 to 370 ppm, the temperature
Plunged 8 degrees Celsius, and the mild tropical climate changed to one similar
To today’s, in which an icy Antarctic drives a strong ocean
circulation.4
From 2.6 million years to 11,430 years ago, was the great ice age known
As the Pleistocene Epoch. CO2 levels were low, varying from 180 to 280 ppm.
Continents were in their present positions, both continental and marine
Fauna were essentially modern, and humans evolved in their present form.5
Thousands of
Years ago
125,000 years ago marks the last inter-glacial interval prior to the most
Recent one which began 11,430 years ago. Atmospheric CO2 was 270 ppm,
And the temperature was 1 degree Celsius warmer than ours in 1950 C.E.
Wholesale melting of glaciers caused the sea level to rise
by 4-6 meters.6
From 11,430 years ago to 1750 C.E., was the most recent inter-glacial interval,
The Holocene Epoch. CO2 stayed between 260 and 280 ppm. The climate
Was stable, conducive to the flourishing of life, and for humans, the rise
Of agriculture, civilization, population numbers, and large coastal cities.7
Now
We have now entered the Anthropocene Epoch, during which humans,
Even if mindlessly, are in control of Earth’s climate. In 1900, the CO2
Level was 295 ppm; in 1950, it was 325; in 2000, it was 385 and rising.
These numbers represent an exponential increase, with no end in sight.
The History of Extinctions
Of the five worst extinctions of life which have occurred to date, all but
The last were caused by rapid global warming. Only the last, 65.5 million
Years ago, ending the Age of Reptiles, including the dinosaurs, was
Caused by an asteroid hitting Earth (on the Yucatan Peninsula, Mexico).8
The laws of physics are unbendable. A warmer climate means less ice.
As glaciers melt, particularly those draining into the North Atlantic,
They freshen the salty ocean, thereby interfering with the sinking of
The Atlantic conveyor current carrying warm water from the tropics.
Arriving near Greenland, the current, by then cold and well-oxygenated,
Would normally sink, bringing oxygen to the lower layers of the ocean.
Now, however, stopped by the less dense fresh water, it sinks at lower
Latitudes, bringing less cold, less oxygenated water to the bottom.
Concurrently, as Earth warms, the poles warm disproportionately –
Much more than the tropics. It is the differential in temperature
Between poles and tropics which drives Earth’s wind and ocean
Currents. A lesser difference means stagnation, both in air and water.
The bottom layer of the ocean, lacking oxygen and now stagnant,
Can no longer sustain aerobic organisms. It can only sustain anaerobic
Bacteria which produce the gas hydrogen sulfide (H2S), poisonous to
Aerobic life. They feast on the rotting plants submerged by high water.
The hydrogen sulfide rises to the surface of the ocean, killing marine
Life on its way. It rises in the atmosphere, killing plant and animal
Life on its way. And upon reaching the stratosphere, it destroys ozone.
Except in a few protected corners and coves, life is decimated.
This is what happens, no matter the historical period,
Whether 439 million years ago, 364 million years ago,
251 million years ago, or 210 million years ago. The
Physics are the same.
History is poised to repeat itself.9
With one caveat.
The sun is warmer now than it was millions of years ago.
Levels of carbon dioxide which in the past would not
Have triggered the extinction process, now well could.
With our current solar radiation, a CO2 level of 1,000 ppm
Would make Earth the second hottest it has ever been.
The four hottest times have brought mass extinction.
Graph
Graph: See page 9 for graph of temperatures mentioned in the poem.
Notes
1. 600-318 million years ago: The Paleozoic Era (542-251), Cambrian Period (542-488), Ordovician Period (488-444), Silurian Period (444-416), Devonian (416-359), and Carboniferous (Mississippian) Period (359-318).
2. 318-299 million years ago: The Paleozoic Era (542-251), Carboniferous Period (Pennsylvanian) (318-299).
The super-continent of Gondwana was formed c.525 million years ago, and disintegrated c.140 million years ago. It extended from the South pole to near the equator, comprising Antarctica, India, Australia, Africa and South America.
3. 299-251 million years ago: The Paleozoic Era (542-251), Permian Period (299-251).
By the Eocene Epoch (55-34 million years ago), CO2 levels had decreased to 800-1,000 ppm.
4. 34 million years ago: Cenozoic Era (65.5-Present), Paleogene Period, previously known as the Tertiary Period (65.5-23); 34 million years ago represents the transition between the Eocene Epoch (56-33.9) and the Oligocene Epoch (33.9-23).
5. From 2.6 million years to 11,430 years ago: Cenozoic Era (65.5-Present), Quaternary Period (2.6 million-Present), Pleistocene Epoch (2.6 million years ago-11,430).
6. 125,000 years ago: Cenozoic Era (65.5-Present), Quaternary Period (2.6-million-Present).
Pleistocene Epoch (2.6 million-11,430).
7. From 11,430 years ago to c.1750 C.E.: Cenozoic Era (65.5-Present), Quaternary Period (2.6-million-Present), Holocene Epoch (11,430-c.1750).
8. 65.5 million years ago: Mesozoic Era (251-65.5-Present), Cretaceous Period (146-65.5).
9. The first four major extinctions:
439 million years ago: Paleozoic Era (542-251), Silurian Period (444-436).
Duration: 2 million years
Extinction: 57 percent of all genera.
Recovery Time to original Level of Diversity: 25 million years.
364 million years ago: Paleozoic Era (542-251), Devonian Period (416-359).
Duration: 20 million years.
Extinction: 70 percent of all species, including 75 percent of the dominant marine species.
Recovery Time to original Level of Diversity: 30 million years.
251 million years ago: Paleozoic Era (542-251), Permian Period (299-251).
Duration: 8 million years.
Extinction: 96 percent of marine species and 70 percent of land species (including 75 percent of land vertebrates).
Recovery Time to original Level of Diversity: The recovery of vertebrates took 30 million years. Together with the next extinction (210 million years ago), recovery to the original level of diversity took 100 million years.
210 million years ago: Mesozoic Era (251-65.5), Triassic Period (251-200).
Duration: 17 million years.
Extinction: 48 percent of all genera.
Recovery Time to original Level of Diversity: Together with the previous extinction (251 million years ago): 100 million years.
References
Principal Reference:
Ward, Peter. 2010. The flooded Earth – our future in a world without ice caps. New York, N.Y.: Basic Books.
P. 9 (125,000 years ago); p. 14 (251-65.5 million years ago); pp. 15-16, 146, 186-192 and 215-217 (mechanism of extinctions); pp. 52-57 (carbon dioxide levels); p. 53 (CO2 level 56-34 million years ago); pp. 53 and 141-143 (CO2 level 34 million years ago); pp. 144-146 (climate 200 million and 2.5 million years ago); p. 146 (thermohaline currents); pp. 180-182 (the Devonian Canning Barrier Reef);
Other References:
Archer, David. 2009. The long thaw – how humans are changing the next 100,000 years of Earth’s climate. Princeton, N.J.: Princeton University.
Hall, Francoise,
2005. “Ask the Mosquitoes.” (Poem). March 19 (13 pages, unpublished). (See Wilson 1992/1999).
2006. “The brief and disastrous Reign of Homo petrolatum.” September 30 (61 pages, unpublished).
Kazlev, Alan, 1998-2002. “The Mississippian Epoch of the Carboniferous Period: 359-318 Mya.” Uploaded on Kheper Site, May 27, 1998. Uploaded on Palaeos Site, April 10, 2002.
http://palaeos.com/Paleozoic/Carboniferous/Mississippian. Updated May 4, 2002. Checked ATW040712. Accessed August 27, 2010.
Prothero, Donald, and Robert Emry (Editors). 1996. The terrestrial Eocene-Oligocene Transition in North America. New York, N.Y.: Cambridge University.
http://books.google.com/books?id=tCwwlEmSdJkC&printsec=fr. Accessed August 26, 2010.
“The transition from the Eocene to the Oligocene epochs (from about 47 to 27 million years ago), was one of the most dramatic episodes of climate and biotic change since the demise of the dinosaurs. The mild tropical climates that characterized the Paleocene and early Eocene, were replaced by the beginning of modern climatic extremes, including glacial ice in Antarctica and modern deep-water oceanic circulation.”
Siegel, Lee. 2000. “The five worst Extinctions in Earth’s History.” September 7.
http://www.space.com/scienceastronomy/planetearth/extinction_sidebar_000907.html. Accessed August 24, 2010.
Wikipedia,
2005. “Late Pleistocene (650,000-0 years BP): Atmospheric CO2 (ppm) and the glacial Cycles (N. American and Alpine Regions). Graph. December 3. Copied from en: Image: Atmospheric_CO2_with_glaciers_cycles.gif. (Tom Ruen).
http://en.wikipedia.org/wiki/File. Accessed August 26, 2010.
2008. “File:Geological Time Scale.png.” Author: Richard Murphy, Jr.
http://en.wikipedia.org/wiki/File. February 24. Accessed August 26, 2010.
2010.
“Carbon dioxide.”
http://en.wikipedia.org/wiki. Updated August 24. Accessed August 28, 2010.
“Extinction Event.”
http://en.wikipedia.org/wiki. Updated August 7. Accessed August 24, 2010.
“Geologic Clock.”
http://en.wikipedia.org/wiki/File. Authors: Woudloper
and Andrew Colvin. June 22. Accessed August 24, 2010.
“Geologic Time Scale.”
http://en.wikipedia.org/wiki. Updated August 23. Accessed August 24, 2010.
“Gondwana.”
http://en.wikipedia.org/wiki. Updated August 10. Accessed August 28, 2010.
“Greenhouse Gas.”
http://en.wikipedia.org/wiki. Updated August 28. Accessed August 28, 2010.
“Ozone Layer.”
http://en.wikipedia.org/wiki. Updated August 24. Accessed August 27, 2010.
“Paleoclimatology.”
http://en.wikipedia.org/wiki. Updated August 13. Accessed August 24, 2010.
“Pleistocene.”
http://en.wikipedia.org/wiki. Updated August 26. Accessed August 26, 2010.
Vostok Petit Data.svg. File. Author: Vostock-ice-core-petit.png.
http://en.wikipedia.org/wiki/File. June 20. Accessed August 24, 2010.
Wilson, Edward. 1992/1999, The diversity of life. New York, N.Y.: W. W. Norton.
Summarized in Francoise Hall, 2005. “Ask the Mosquitoes.” (Poem). March 19 (13 pages, unpublished).
Wormuth, Laura, 2008. “Mass Extinctions – through History and today. New Paleontological Database refines Extinction and Recovery Rates.” Evolution.suite101. October 28. (Data taken from Prothero, Donald. 1998. Bringing fossils to life).
http://evolution.suite101.com/article/cfm. Accessed August 28, 2010.
Zanazzi, Alessandro, Matthew Kohn, Bruce MacFadden and Dennis Terry. 2007. “Large Temperature Drop across the Eocene-Oligocene Transition in Central North America.” Nature, Volume 445, Number 7128, pp. 639-642. February 8.
http://www.nature.com/nature/journal/v445/n7128/abs/nature055. Accessed August 26, 2010.
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