Ways to measure carbon dioxide (co2)?

Question

theres tree rings, weather satellites, weather balloons..any other ways?

Answer 1

Tree rings are a very indirect indicator at best.  

Some detectors are based on the change in resistance of a metal strip as the metal adsorbs CO2.  Other gases such as CO will also adsorb, so the method is subject to error.  

The best methods are optical.  A research grade FTIR instrument with 0.01 cm^-1 resolution and a long path length gas cell is ideal.  Bomem used to make such instruments for satellite and balloon measurements.  The company was bought by European interests and and is now more interested in quality control applications.  A cavity ring down spectrometer with a bolometer or a MCT detector is the best choice for measuring very low concentrations.  Any research grade FTIR spectrometer will give the CO2 concentration to 4-5 significant figures.  On the cheap, LED's and matching thermopiles are now available from Roithner

http://www.roithner-laser.com/All_Datash...

at wavelengths useful for CO2 detection.

Answer 2

U can buy a CO2 detector . Industry uses them for safety for the people working around dry ice.