The greenhouse effect of the atmosphere is the main factor of possible climate changes of anthropogenic origin. The growing pollution of the atmosphere leads to an increase of the concentration of such gaseous components as sulphur and carbon dioxides, carbon oxide, halocarbons, nitrous oxides, etc. Of great importance is also the consideration of the aerosols, both injected directly into the atmosphere and formed as a result of the conversion of chemical gas into particles (first of all, it concerns the sulphate aerosol). All the above gaseous components, as well as aerosols, have the absorption bands in the IR spectral range, which determines their contribution to the greenhouse effect of the atmosphere, mainly governed by water vapour and carbon dioxide. The traditional attention to the problem of the CO2 contribution to the greenhouse effect has somewhat overshadowed the significance of the different components. The data characterizing the significance of the different components of the greenhouse effect are considered. The results of studying the absorption spectra of methane, nitrous oxides, sulphuric gas, ammonia, nitric-acid vapours and other components are discussed. The assessments of their contribution to the greenhouse effect are given. The important role of the small-size fraction of the atmospheric aerosols as a factor of the greenhouse effect is discussed. Both the analysis of the causes of the Earth's climate variability and the relevant investigation of the atmospheric greenhouse effect determine the expediency of analysing the conditions of the greenhouse effect formation on other planets, that is the consideration of different planetary atmospheres as the specific models of the greenhouse effect formation. To solve such a problem, data are needed on the composition and structural parameters of the atmospheres and the quantitative characteristics of the absorption spectra associated with the specific conditions of various atmospheres. In connection with this, laboratory studies of the IR absorption spectra of the synthetical CO2 atmospheres were carried out. Some results from these studies are discussed. Calculations of the thermal-emission fluxes' spectral distribution in the atmospheres of Mars, Venus and Jupiter were performed to analyse the conditions of the greenhouse effect formation in the atmospheres of these planets. Calculations were made which concern the optical properties of Venus clouds and dust aerosols of Mars,i.e. the contribution of clouds and aerosols into the greenhouse effect was analysed. The conditions favourable to the antigreenhouse effect formation are specified.