cheee wrote:Your figures are a bit off. I'm not sure, but you might be doing it by mass (weight), though it doesn't look right for that even.
Answer:
Nitrogen: $77.00
Oxygen: $20.00 (animals NEED this to live)
Water: $ 2.00 (this is the ‘real’ GHG)
Argon: $ 0.95 (that’s right, 25x the amount of CO2)
CO2: 4 cents (plants NEED this to live)
Other: 1 penny
By volume (which would be your molecule count), for dry air, it should be:
Nitrogen (N2) $78.08
Oxygen (O2) $20.95
Argon (AR) $0.93
Carbond Dioxide (CO2) $0.03
Other $0.01
I've left out water (H2O) because it's so variable. Water content is highly dependent on air temperature, as well as on humidity. The relationship is fairly complex. If you specify a temperature and a relative humidity, H2O content can be calculated. And additional H20 will pull a few cents from the Nitrogen and Oxygen "budget" to keep your total at $100.00.
You’re correct in both your numbers and your commentary.
One rarely sees water included in any listing of the components of air. I think that’s a mistake ... it’s important that folks realize that it’s both significant and far more prevalent than CO2. I chose 2% for water since it’s in the middle of the range most often stated.
I’ve not seen a specific overall average ‘percentage of water in the atmosphere’. While it might not be easy to come by, I’d bet it’s fairly constant when averaged over the whole globe.
Also, I intentionally used very ‘round’ figures. I originally came up with this as an exercise for Jr. High School aged Girl Scouts (my wife leads a couple of troops). The idea was to give them $99. of monopoly money plus a dollar’s worth of change and see how closely they could get to the actual numbers. When they later see the ‘real’ level of CO2 in the atmosphere ... well, it’s something they’d be likely to remember.
Anyway, thanks for the response ...