Not an O wasted

There's a lot of talk about climate change and CO2 but little talk about the depletion of oxygen in the atmosphere:

   

The graph shows a ratio of oxygen to nitrogen. Here is the math:

δ = ((O2/N2)sample – (O2/N2)reference)/ (O2/N2)reference)

where (O2/N2)sample is the O2/N2 mole ratio of an air sample and (O2/N2)reference is the O2/N2 mole ratio of their reference.  The reference is based on tanks of air pumped in the mid 1980s which are stored at the Scripps Institute laboratory in La Jolla, California. 

This kind of "science" is truly the definition of half-assed.

If all of a sudden, half the atmosphere is filled with some random gas, say helium, the ratio of oxygen to nitrogen stays the same, however, in reality, the percent of oxygen in the atmosphere halves in concentration. By using a ratio, and not measuring the actual percentage of oxygen in a volume of "air" the data can be easily manipulated.

Why can't we just do things properly in all aspects of society? Probably because it's harder, and requires more work to do so.