We have analyzed atmospheric spectra obtained with the Fourier transform spectrometer on Kitt peak, in Arizona, for absorption by CO2 and CH4. During the period 1979--1985 we find that the CO2 total column amount was increasing at a rate of 0.4%/yr and that CH4 was increasing at a rate of 1.1%/yr. This is in substantial agreement with air sampling measurements from other sites. In addition, a weak seasonal variation of ~2% is detected in CO2, but none is seen in CH4.