The CO2 Debate

Reme,

First, thank you for your patience. It's been a busy week for me, multiple papers, multiple mid-terms, a group project and prepping for a James Joyce presentation (you think arguing global warming is difficult...try explaining Joyce).

I said earlier I wanted to address the CO2 argument, which I will do in this post. I realize your own post regarding CO2 also covered other topics, including feedback loops, which I would like to comment on as well, but will do so at a later date.

This post here is actually the same post I threw up a year ago when we were having this same debate then. I have gone back only to cut it down where it isn't relevant (direct commentary to questions not related to CO2).

While the point of this post should be clear, what I want to emphasize from the start is the complexity of what we're talking about and the danger of over-simplifying it.

In your post you explained the basic argument I hear from all Global Warming Advocates (GWAs as they will be referred to in this post), and I find that argument naively simplified. It works well in convincing an uneducated public to say that the earth is a greenhouse and CO2 heats it up, but by ignoring the vast complexity of a system like global climate GWAs are, at best, clouding the issue, and, at worst, being willfully, manipulatively dishonest.

My hope here is to engender at least a small sense of how the simple CO2 explanation given by GWAs is only a minute glimpse of a much larger picture, and to furthermore emphasize how GWAs have blown that glimpse far, far out of proportion.

Here we go.

If I’ve got it right, the general, popular global warming argument goes like this: Mankind has drastically increased the amount of carbon dioxide in Earth’s atmosphere, thus causing an ever-increasing Greenhouse Effect because the CO2 traps heat within the atmosphere. The result is Earth’s temperature rises and rises, eventually spiraling out of control.

This entire argument rests on the assumption that Earth’s atmosphere acts exactly like a greenhouse, so let us begin there.

A greenhouse raises temperature within it by controlling convection (the circulation of the air). Sunlight comes in through the glass, warms the ground inside, the ground warms the air, the air rises but cannot escape, and thus the temperature simply continues to rise. When you need to cool a greenhouse, you open a window on the roof and a door below, creating a convection current, and the air circulates and cools.

The Earth’s system, however, does not operate in this manner (the big giveaway should be the lack of a giant window in the sky). The Earth does employ a “greenhouse effect,” but it does so through modulating radiation, which is not the way an actual greenhouse works.

The importance of this distinction is that “greenhouse gases” in the atmosphere do not behave like the glass ceiling of a greenhouse, preventing all the heat from leaving. This is a common misunderstanding.

To understand the Earth’s own “greenhouse effect,” we must first understand the larger system of energy exchange. The drastic oversimplification of this system is this:

The Sun sends out strong, shortwave radiation. This radiation moves through our atmosphere and is absorbed, and then a portion of it is emitted back as longwave radiation (this is because the Earth isn’t as hot and energetic as the sun). This longwave radiation moves back through the atmosphere and escapes into space.

The more complex reality includes other factors:

The atmosphere is a series of layers and includes clouds and other gases. Not all of the radiation from the sun reaches the surface; indeed much of it bounces off the atmosphere and never enters Earth at all. Radiation leaving the surface must also pass back through many stages, thus encountering another complicated journey.

What should be immediately clear is that the general belief that our atmosphere acts as a barrier, “trapping” heat inside the system is a myth. Radiation enters and leaves continuously, and while radiation may be slowed down on its journey back and forth, it is never fully “trapped” within the system. No matter how many layers it has to pass through, it will eventually exit the system.

Again, the difference we need to fully grasp is the difference between a convection system, which fully traps air, and the Earth’s radiation system, which allows flow of radiation in and out.

Now, with that understanding, let us address the “greenhouse effect” that actually occurs on Earth, and in the process abandon our earlier misunderstanding of a glass ceiling.

First, it is critical to grasp that while the Earth’s “greenhouse effect” has been given a bad rap, it is vital for life on our planet. Minus out the “greenhouse effect” and we don’t exist.

This critical system works like this:

A portion of the radiation emitted back from the Earth is absorbed by water vapor and greenhouse gases before then being emitted once again, which allows the surface and atmospheric temperature to rise. This interplay within the system is what keeps our planet at a hospitable temperature.

If you could remove this mechanism, the temperature would drop by 35 degrees, well below the freezing point of water.

Obviously then, while we can discuss the fluctuations of this “greenhouse effect,” it is a serious mistake to believe that our goal should be to remove it altogether.

The core issue GWAs raise at this juncture is that C02 in the atmosphere acts as a major force within the system, causing massive fluctuations in temperature by absorbing major quantities of radiation and bouncing it back to the surface.

To figure out if this is true, we must first know what the atmosphere is made of and how much C02 is currently there.

The composition of Earth’s atmosphere is comprised of the following gases: Nitrogen, Oxygen, Water (in the form of vapor), Argon, Carbon Dioxide, Neon, Helium, Methane, Krypton, Hydrogen, Nitrous Oxide, Xenon, Ozone, Nitrogen Dioxide, Iodine, Carbon Monoxide, and Ammonia. I have ordered them from largest quantity to smallest quantity.

Nitrogen makes up 78.08% of the atmosphere. Oxygen 20.95%.

That means over 99% of the atmosphere is Nitrogen and Oxygen.

C02, which GWAs spend so much focus on, makes up .0383% of Earth’s atmosphere.

That is less than half of one percent.

Surely then, C02 must be an incredibly powerful “greenhouse gas,” so incredibly powerful that the amount of radiation it can absorb can simply overpower the effects of over 99% of Earth’s atmosphere.

This is a pleasant fantasy GWAs would like to believe. In reality, C02 is one of the weakest absorbents of heat in the atmosphere (Methane is capable of absorbing 21 times the amount of heat of C02, Nitrous Oxide 310 times). Also, since neither Nitrogen nor Oxygen is a “greenhouse gas”, even if we added all the “greenhouse gases” together we’re still talking about less than 1% of the atmosphere.

In fact, only one item on the list can truly be called a major player:

Water vapor.

Water vapor, especially in the form of clouds, accounts for between 90% and 95% of Earth’s “greenhouse effect,” a fluctuation that is never entirely stable at one number because the water in the atmosphere is constantly changing (due to elevation, temperature, wind, etc.). Clouds are the single most important and determinant “greenhouse gas,” absorbing more and emitting more radiation than anything else in the system.

To go further, one must recognize that all gasses can only absorb radiation within a narrow bandwidth of the light spectrum (C02 absorbs longwave, infrared and far-infrared radiation only in three narrow bandwidths, at 2.7, 4.3 and 15 micrometers...which means only 8% of the Earth’s emitted radiation can be absorbed by C02 at all), and that each of the “greenhouse gasses” is, for lack of a better metaphor, in competition with the rest for the chance to absorb radiation. And all of these gasses are effected by an atmosphere that is not static…it is constantly in motion, as is the air, the ocean currents, the Earth itself, everything.

So…to come back to the central argument.

Of all of the radiation from the Sun the Earth can possible take in, roughly half reaches the surface. Of that half, only some 15% is absorbed into the atmosphere when emitted from the Earth.

Of the 100% composition of Earth’s atmosphere that will absorb that 15% energy, C02 makes up a slight .0383%.

And that .0383% of C02 is only physically capable of absorbing 8% of the emitted radiation.

These are the numbers. They are plain and simple numbers, and you may interpret them how you choose.

GWAs offer us the interpretation that the .0383% of C02 in the atmosphere is responsible for all of the temperature fluctuation of the last century, and that this less than half of one percent of the atmosphere will cause the end of mankind as we know it.

GWAs offer that the .0383% of C02 in the atmosphere plays a larger and more powerful role than 99% of the atmosphere, and that it outweighs the effects of water vapor and clouds, which are admitted by climatologists to play the largest role in Earth’s “greenhouse effect.”

GWAs offer that this minuscule amount of carbon is more important than all other factors, from natural interglacial warming to urban sprawl to the effect of the Sun itself.

Now, I imagine that you are probably saying to yourself that even if this amount is so small, human beings have already added to it, and will keep adding to it, and so there will be more and more C02 in the atmosphere, wreaking more and more havoc, so that we need to ACT NOW OR ELSE.

Which would be logical if humans accounted for the majority of carbon emissions into the atmosphere (we don’t…human activity accounts for roughly 3.4% of annual carbon dioxide emissions…the other 96.6% is entirely natural) and if the accumulation of C02 didn’t have a logarithmic effect (except it does…which means that the more C02 you add, the less effect the additional gas has…imagine putting up window blinds, and then another set of blinds behind those, and then another set, on and on…each successive set has less effect than the one before it). Actually, the truth is that advocating for a massive C02 reduction would mean advocating for the destruction of the natural world producers of C02…kind of ironic, I think.

Still, you could argue that cutting out the major sources of human production of C02 emissions would lessen the amount of C02 in the atmosphere, thereby DOING OUR PART to help keep the planet at its current temperature. This would at least be making an effort.

Which would be logical if the major sources of human production of C02 (factories and cars) didn’t also produce aerosols, which act as a cooling mechanism in the atmosphere, thereby canceling out the effect of C02 in the first place (cooling mechanisms are actually an entire focus GWAs try to ignore, both natural and man-made)

The truth, my friend, is that the GWAs concentration on C02 emissions is based upon bad science, misinterpretation and fundamental misunderstandings of the way our world works.

And, to put it rather bluntly, folks still making this argument simply don’t know what they’re talking about.