Abstract

In this paper we show that the concept of cooling and settling of the middle and upper atmosphere formulated in 1999 finds new experimental confirmations in various measurement data of the parameters of both the neutral and ionized components of the middle and upper atmosphere. At the same time, it is becoming more and more obvious that it is impossible to explain the entire range of observed long-term trends in the atmosphere and ionosphere by a mere increase in the CO₂ content in the atmosphere. In particular, the main source of CO₂ entering the atmosphere is the combustion of hydrocarbon fuels on an industrial scale, which binds free oxygen with carbon. On the other hand, oddly enough, the processes caused by the decrease in the O₂ content in the atmosphere are not considered in any theoretical model designed to explain the observed phenomena. In the meanwhile, the effect of a sharp drop in the O₂ concentration above the turbopause level is clearly recorded from the data on the response of the ionosphere to solar flares.