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Global warming from a former petroleum geologist's viewpoint

To understand greenhouse warming from human-generated carbon dioxide requires aproper geological grasp of two things: First, the photosynthesis-respiration cycle, themost important element of Earth's delicately balanced surface environment; second, theenormity of geological time over which the worlds petroleum accumulated, in contrast tothe century and a half during which we have burned half of it.

Photosynthetic organisms transform sunlight, water and carbon dioxide intohydrocarbons containing stored chemical energy, with a byproduct of free oxygen. Thestored energy is released by respiration, whereby animals and fungi power theirexistence by "burning" the hydrocarbons with oxygen, releasing "waste" water andcarbon dioxide, and thus completing the cycle.

The photosynthesis-respiration cycle is very efficient, but small amounts of hydrocarbonsescape respiration by being buried in swamp deposits or in oceanic sediments.

Deep burial of the swamps transforms the organic material into coal. When the oceanichydrocarbons are buried to depths of about 2 to 5 kilometers, the elevated pressuresand temperatures slowly cook them into oil and methane, which migrate upward, beingof low density. The petroleum is trapped if it enters the pores in sands or limestones thatare enclosed on the top and sides by impermeable rocks.

Given enough time, all coal and petroleum eventually must undergo one of two fates.Either they are buried so deeply that Earths internal heat rips the hydrocarbonmolecules apart, or uplift and erosion of the carbon-bearing rocks releases the coal andpetroleum back into the surface environment. The Canadian and Venezuelan tar sandsare oil deposits exposed by erosion that have lost their volatile components.

Natural processes over the great lengths of geological time have achieved a roughbalance between carbon storage and release, leaving the global environmental balanceessentially undisturbed, leaving a quasi-steady-state amount of carbon stored in Earthscrust.

Ignoring coal and methane to look only at oil, the best geological estimates are: sinceabout 600 million years ago, when the oldest oil we use was formed, the Earth hasstored only about two trillion barrels. On average, this is little more than 3,000 barrelsannually.

The most prolific oil-generating period was the 20 million years or so of late Jurassic tomid Cretaceous time, from about 110 to 90 million years ago, when more than half of theworlds oil including all in the Middle East was stored. Even during that period, the

Earth stored only about 50,000 barrels annually.

At present, Humanity burns about 29 billion barrels a year. That is what the Earth hasstored, on average, over about nine million years.

In other words, the carbon dioxide that Nature took out of the atmosphere and tuckedaway as oil in rocks over nine million years, we return to the air in one year. Over the

8/6/2019 07 0326 Global Warming From a Former Petroleum Geologist

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last one and a half centuries the blink of an eye in geological terms we have burneda trillion barrels of oil and have dumped its carbon dioxide waste back into the air.

Even if TWICE as much oil has accumulated in the Earth's crust as our best estimates -a totally unrealistic figure that not even the most wildly optimistic "cornucopians" claim,we would be pumping into the air in one year the carbon dioxide that nature had

sequestered in the rocks for over four million years.

Comparable amounts of carbon dioxide are also pumped into the atmosphere by burningcoal and natural gas. To the total 6.5 billions of carbon returned to the air every year,deforestation also adds another 1-2 billion tons.

Thus is Humanity inflicting on Earth's delicately balanced living environment one of themost severe traumas it has ever had to endure. The resulting fever is what we callAnthropogenic Global Warming.

Hurricanes Katrina and Rita may be only tiny symptoms of that trauma.

The Earth occasionally undergoes a severe trauma, such as the impact of the Chixulubmeteorite, ten kilometers in diameter, that 65 million years ago caused massiveextinctions of oceanic and terrestrial life including the dinosaurs. Burning a trillionbarrels of oil plus an equivalent amount of coal and natural gas in less than twocenturies is a geological catastrophe of similar magnitude.

Given enough time after catastrophe, the Earths surface environment and its life havealways managed to restore equilibrium, including equable temperatures. They will do soagain, regardless of whether humankind survives or not.

But such a recovery cannot possibly begin while humanity continues to accelerate itsuse of fossil fuels.

Even if we were to stop all fossil-fuel combustion today, it will still take a very long timefor our global environment and ecosystems to recover.

Kelvin S. RodolfoProfessor EmeritusDept. of Earth & Environmental SciencesUniversity of Illinois at Chicago845 W. Taylor St.Chicago IL 60607 U.S.A.(312) 243-8241 or (312) 733-0617krodolfo@uic.edu

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