The Climate Suspense Story, Who Dunnit?      CO2?

Chapter 1, The Moon, and implications for the earth without oceans or an atmosphere

Our story begins with the moon, the same distance (on average) from the sun.  It has a day (with respect to the sun) rotating on its axis once in about 27 earth days, but pertinent to our story, it has no atmosphere.  During the moon’s day, the surface of the side exposed to the incident solar irradiance is warmed, while it simultaneously radiates energy to outer space.  The incoming solar irradiance wins this tug of war, raising the temperature of the surface to a toasty 253oF (123oC, 396oK around the equator), well more than enough to boil water.  During the moon’s night, without the solar irradiance, there is only the radiation of the moon’s surface to outer space, and the moon’s surface cools to a frosty -243oF  (-153oC, 120oK, again around the equator).  Not that it matters much, but the Anthropogenic Global Warming (AGW) movement seems to love calculating it, the grand lunar average at the equator is a chilly -27.7oF (-33oC, 240oK) (estimated from a plot of heat capacity of the moon from “Lunar Maddness, Science of Doom, given max and min temperatures, which came from website: http://www.space.com/18175-moon-temperature.html”).  Calculating an area weighted temperature average for the whole Lunar Surface gives 288,9oF (142.7oC, 415.7oK).

This initial part of the story is “simple”, and it is real, not a thought experiment, but it sets the stage.

Now consider the earth.  Its heat capacity will be different compared to the moon, but consider it without oceans and an without atmosphere, and being, on average the same distance from the sun as the moon, conditions would be similar, but primarily influenced differently because of a much shorter period of rotation on its axis.  This would not allow as much heating during the day, nor as much cooling at night, as would be the case on the moon.  So the temperature extremes would not be as great as they are on the moon.

[Could we calculate what those extremes for the earth, again with no atmosphere or oceans?]

Chapter 2, The Earth with Only N2 and O2 in the Atmosphere (but without oceans and without evaporation or consider oceans with evaporation somehow suppressed?)

The earth is more massive than the moon, has a much shorter “day”, and has an atmosphere.  To keep things simpler, first consider that the atmosphere is composed only of N2 and O2.  The first, most critical issue for us would be that without CO2, there would be no life on earth, even though, there are oceans with lots of water, the surface of the earth being about 71% covered with water.  To comply with the title of this chapter we have to have some mysterious mechanism to prevent water from evaporating into the atmosphere, but since we are effectively doing a thought experiment, we will postulate that no water is allowed to evaporate into the atmosphere.

So the question is what influence does the atmosphere have on the earth’s climate – no water vapor or so-called “greenhouse gases” that can absorb or emit infrared radiation?

Incoming energy from the sun, solar radiation is 1367 W/M2, called the Solar Constant though not really a constant.

Ideal Gas Laws:   https://tallbloke.wordpress.com/2012/02/25/stephen-wilde-the-myth-of-backradiation/

Chapter 3,  The Earth, Adding Water Vapor into the Atmosphere

[Fill in later.]

Chapter 4,  The Earth, Adding Also Carbon Dioxide into the Atmosphere, the CO2                       Story

“A day in the life of a CO2 molecule”, Geologically Speaking:

When the earth was formed and developed and atmosphere, it was heavily dominated by CO2, as are now the sister planets, Venus and Mars.  Before discussing Earth more, consider conditions on Venus and Mars.

Comparison of Venus, Earth, Mars:

Venus has an atmosphere of 96.5% CO2.  Given that CO2 is one of the heaviest gas molecules, with an atomic weight of 44, compared to N2 at 28, O2 at 32, and water vapor at 18, the Venusian atmosphere is correspondingly massive.  The tremendous mass of the Venusian atmosphere through the Ideal Gas Law gives a very large pressure and temperature at the surface of the planet, with the temperature being further increased due to its closer proximity to the sun.  Furthermore, Venus has sufficient mass to keep its atmosphere.  As a result the surface of Venus is very hot, around 740 oK (467 oC, 873 oF), with the very high temperature being explained by the Ideal Gas Law and the proximity to the Sun.  Believing that CO2 is acting as a “greenhouse gas” to heat the surface is superfluous, and not true.

From Wikipedia, “The atmospheric pressure at the surface of Venus is about 92 times that of the Earth, similar to the pressure found 910 metres below the surface of the ocean. The atmosphere has a mass of 4.8×1020 kg, about 93 times the mass of the Earth's total atmosphere. The density of the air at the surface is 67 kg/m3, which is 6.5% that of liquid water on Earth.  The pressure found on Venus's surface is high enough that the carbon dioxide is technically no longer a gas, but a supercritical fluid. This supercritical carbon dioxide forms a kind of sea that covers the entire surface of Venus. This sea of supercritical carbon dioxide transfers heat very efficiently, buffering the temperature changes between night and day (which last 56 terrestrial days).”

Mars has an atmosphere, also dominated by CO2 at 96%, but Mars is nearly 10 times less massive than the Earth and as a result has lost much of its atmosphere, with its mass being over 200 times less than the Earth’s.  Mars is much colder than the Earth, and as for Venus, the distance from the Sun and the Ideal Gas Law account for nearly all of the colder temperature.  The very dominant “greenhouse gas”, CO2, cannot overcome these factors.

Given that the impact of CO2 on Earth’s two sister planets is minimal to non-existent, that is also likely to be true on Earth, especially given the miniscule amount present on earth.  Early in the Earth’s geologic history, when CO2 dominated the Earth’s atmosphere by much more than 1000 times the present value, there was no runaway temperature due to the so-called “greenhouse effect”.  It is very likely that the very high CO2 level contributed to the onset of life on Earth.  And it was only after life developed that O2 began to become a major gas in the Earth’s atmosphere.  Carbon is essential to life.

If one looks at the geologic history of CO2, after the initial very high level in the atmosphere, the presence of life, began a continuous sequestration of Carbon, that continues to the present.  A noteworthy observation is that more than 95% of the Carbon in the Earth’s crust/bio-sphere, is contained in Limestone!  How did it get there?

The “segregation coefficient” for CO2 in the air compared to sea water is 50:1, meaning the equilibrium concentration of CO2 in the sea water is 50 times that in the air.  So the Earth’s oceans store vast amounts of CO2, vastly more than the atmosphere.  Thus the ocean also acts as a “short-term” buffer for CO2 in the atmosphere.  When the atmospheric temperature rises (it fluctuates much more than does the oceans temperatures), CO2 is released from the oceans to the atmosphere, with the process being reversible.

In climate discussions much is made of the so-called “Carbon Cycle”, typically described as:

• Carbon moves from the atmosphere to plants through photosynthesis.
• Carbon moves from the plants to animals, up the food chain.
• Carbon moves from animals to the atmosphere through respiration.
• Carbon moves back to the atmosphere as living things die and decay.
• Carbon also moves to the ground when living things die and decay, frequently becoming fossil fuels, which, when burned, return Carbon to the atmosphere.
• Carbon moves from the atmosphere to the oceans, and from the oceans back to the atmosphere.

This description of a Carbon Cycle is extremely short-term, geologically speaking, and is largely irrelevant to the long-term Geological Carbon Cycle in that it omits the major source of CO2 to the Earth’s Bio-Sphere and also the major ultimate “Sequestration” of Carbon.  Seldom is the formation of Limestone mentioned, even though, the “noteworthy” comment above is that 95% of the Earth’s Carbon is contained in Limestone!  If the Earth’s atmosphere initially had a very high Carbon content, and now 95% of the total Carbon is contained in Limestone, there must have been a dominant, long-term progression of Carbon from the atmosphere to Limestone.  And looking at the geologic record, at least over the last 600 million years the CO2 level in the atmosphere has dropped from around 7,000 ppm to today’s 380 ppm or so.  (Prior to 600 million years, the CO2 level was much higher.)

Limestone is a sedimentary rock, that is primarily Calcium Carbonate (CaCO3).  It forms primarily in warm, shallow waters as an accumulation of organic debris, and shells, coral, among others, and is then compressed and the combination of pressure and heat converts the material to rock.  The bottom line is that CO2 from the atmosphere is being consumed by life forms and it is eventually converted to Limestone.  CO2 in the atmosphere is essential to life, and with the dramatic reduction of atmospheric CO2, the Earth’s, geologically speaking, is at an all-time low.  In fact the net removal of CO2 from the atmosphere, is leaving us only a little more than a safety factor of two, from CO2 levels being so low that plant life, and therefore all animal life, including humanity, cannot continue to be supported.  With no geological, historical evidence of climate disasters due to high amounts of CO2, worrying about human burning of fossil fuels thus borders on insanity!

Given that CO2 is being systematically removed from the atmosphere over geologic time, dramatically reducing its concentration in the atmosphere, why is there any remaining CO2 left in the atmosphere at all?  The answer lies in Plate Tectonics that are crucial to life on Earth, along with the physical mass of the Earth, and its proximity to the Sun.

The Earth’s physical mass is sufficiently large to maintain its atmosphere, preventing it from escaping to space as has happened on Mars.  The distance from the Sun provides temperature ranges compatible with requirements for life, along with.  The Earth possessing abundant water is also a major requirement. 

The role of Plate Tectonics may not be so obvious.  But as continents drift and some subtend under others, deep trenches form deep in the oceans, that are locations for thermal vents from which copious amounts of CO2 are fed to the oceans and ultimately to the atmosphere over geologic time.  Volcanos (either underwater in the oceans, or on land) also spew vast amounts of CO2 ultimately to the atmosphere during eruptions.  In either case, large amounts of CO2 from deep in the Earth are brought to the surface to feed the Geological Long-Term Carbon Cycle.

Human burning of fossil fuels is part of the very Short-Term Carbon Cycle discussed initially, and cannot play a major role in the Long-Term Carbon Cycle.  The human contribution to atmospheric CO2 remains very small, generally acknowledged to be around 3%.

“A day in the life of a CO2 molecule”, in Real-Time:

[Discuss what happens to a CO2 molecule on a daily basis in the atmosphere with respect to absorbing and re-emitting IR radiation and influence on Earth’s temperature.]