Why Carbon Dioxide Cools the Planet

If we replaced the air in our atmosphere with pure carbon dioxide (CO2), how much would the temperature increase? If carbon dioxide causes global warming, then the temperature increase should be astronomical!

To answer the question, we need to determine how much heat energy per cubic meter of atmosphere the sun and the earth provide. This figure can vary depending on the time of year, how close the earth is to the sun, and other variables.

But on any given day, the sun and earth will provide X amount of heat energy, and on any given day an atmosphere of pure carbon dioxide should be much much hotter than an atmosphere of air. So the number we use for this value can be arbitrary. We can plug in any value as long as we plug the same value throughout the calculation--and the results will be consistent with other values used for the same purpose.

I chose the value of how much heat it takes to raise the temperature 14 degrees Celsius. Typically when I awake in the morning, the summer temperature is around 24 degrees Celsius (75 degrees F) and by midday, when the sun is most intense, the temperature shoots up to 38 degrees Celsius (100 degrees F). I used the following formula (you can pull out of any college physics book) to determine the value:

Q = cm(T1 - T2).

Where Q is the amount of heat energy acting on the atmosphere; c is the specific heat coefficient of air (1.2754); m is the mass of the air (1.2754 kg is the mass of air in one cubic meter) ; and T1-T2 is the temperature change (38 degrees minus 24 degrees is 14 degrees) . Here's what I get when I plug in the numbers:

Q = 1.012 * 1.2754 kg * (38 - 24) = 18.07 kJ per cubic meter.

This result shows that when 18.07 kilo-joules per cubic meter of energy is provided by the sun and earth, the temperature rises 14 degrees Celsius.

That is a pretty hot summer day! But according to the greenhouse theory, we can get the day much hotter if we just add CO2. In an atmosphere of pure CO2, the density would be 1.98 kg per cubic meter. So the mass we will plug in to the equation will be 1.98 kg. The specific heat coefficient for CO2 is .839, and of course the sun and earth's heat energy is 18.07 kJ per cubic meter. Now the moment of truth as we determine the value of T1 (temperature for CO2):

18.07 = .839 * 1.98 kg * (T1 - 24)
T1 = (18.07/.839 * 1.98 kg) + 24 = 34.89 degrees Celsius

Whoa! Hold the phone! If the atmosphere was pure CO2, the midday temperature would be cooler?! Let's round off 34.89 to 35 degrees C.
OK, that's a little bit warmer--but it is still 3 degrees C cooler than an atmosphere of air. 38 degrees - 35 degrees = 3 degrees.

The final CO2 temperature in Fahrenheit degrees is 95 degrees. So the temperature would be 5 degrees cooler on the Fahrenheit scale (100 - 95 = 5).

So what is causing global warming anyway? Definitely not CO2. Global warming has been going on for the last ten thousand years due to the fact our planet is in an interglacial period of an ice-age cycle, or to put it more simply: global warming is the result of natural causes.

However, we do have to be concerned that CO2 could cause global cooling. How much global cooling would result if we doubled the amount of CO2 in the atmosphere?

Well, the math shows that in a pure CO2 atmosphere we can expect a decrease in temperature of about 3 degrees C. Currently CO2 makes up about .0334% of our atmosphere.

If the amount of CO2 is increased to .0668%, we then need to calculate a new specific heat coefficient and mass for air that includes more CO2.

(X = the specific heat coefficient of air with twice as much CO2 )

X = (.000334 * .839) + (.999666 * 1.012)
X = .000280226 + 1.011661992
X = 1.01942218

Now let's find the mass (per cubic meter) of air with twice as much CO2:

Mass (M) = (.000334 * 1.98 kg) + (.999666 * 1.2754 kg)
M = .00066132 + 1.274974016
M = 1.275635336

We are ready to plug in X and M into our equation:

18.07 = 1.01942218 * 1.275635336 kg * (T1 - 24)
T1 = (18.07/1.01942218 * 1.275635336 kg) + 24 = 37.89560733 degrees C

38 degrees Celsius - 37.89560733 degrees C = .10439267 degrees.

Therefore, if we double the amount of carbon dioxide in the atmosphere, the temperature will drop about a tenth-of-a-degree--and all HELL WILL BREAK LOOSE!

According to some alarming stats I read, we humans are increasing CO2 levels in the atmosphere to the tune of 3% per year! (See http://www.physorg.com/news82381987.html.)

If that figure is correct, we on the planet earth can expect CO2 levels to double in 24 years and a temperature drop of one-tenth-of-one degree!--assuming, of course, the natural global warming period is over and temperatures will remain constant absent human industrialization. But you know what happens when you assume: you make an "ass" of "u" and "me."