Atmospheric Composition

With no understanding of the atmosphere and it's composition, it is easy to see why someone might question how we could change the climate. The atmosphere is really big. But to get this in perspective, you really only need to know how much of the atmosphere keeps us warm.

Generally speaking, looking at the pre-industrial atmosphere, if you don't consider water vapor (a larger variable gas), the atmosphere is about 78% Nitrogen and 21% Oxygen. So, 99% of the atmosphere is accounted for in those two gases. The last one percent includes various trace gases, some are greenhouse gases, and some are not.

To get that in perspective, think about it like this. the natural greenhouse gases are CO₂, CH₄, and N₂O. These gases comprise less than 300ths of a percent of our pre-industrial atmosphere. Then of course add water and stir :)

If it were not for that tiny fraction of our atmosphere that are greenhouse gases, we would be a giant frozen ball in space. It's as simple as that.

Once you understand that you don't need to change the whole atmosphere to change the climate, or climate forcing... and once you understand that if naturally it's around 300ths of a percent that keeps us warm, you can see that if we change that 300th's of a percent to 400th's of a percent, you begin to understand how human industrial processes can change the climate by adding greenhouse gases which changes the forcing levels.

Table 7a-1: Average composition of the atmosphere up to an altitude of 25 km.

* variable gases

Links

• http://daac.gsfc.nasa.gov/acdisc/
• http://disc.sci.gsfc.nasa.gov/acdisc/
• http://www.ndsc.ncep.noaa.gov/
• http://www.usgcrp.gov/usgcrp/ProgramElements/atmosphere.htm
• http://sedac.ciesin.columbia.edu/mva/iamcc.tg/eosdata.html
• http://www.physicalgeography.net/fundamentals/7a.html

Atmospheric Science:

• 2009 http://www.realclimate.org/index.php/archives/2009/04/yet-more-aerosols-comment-on-shindell-and-faluvegi/
• Water vapour: feedback or forcing? () ()
• Et Tu LT?
• The tropical lapse rate quandary
• Busy Week for Water Vapor
• More satellite stuff
• Naturally trendy?
• Cloudy outlook for albedo?
• On a Weakening of the Walker Circulation
• The sky IS falling () ()
• On Mid-latitude Storms
• Uncertainty in polar ozone depletion?
• Tropical tropospheric trends
• Butterflies, tornadoes and climate modelling
• Tropical tropospheric trends again
• Tropical tropospheric trends again (again) () ()
• Ozone holes and cosmic rays () ()