The book, in a popular form, elucidates the problem of the Earth climate change. It considers the causes of natural climatic variations and their character during long-lasting time periods in the past, taking into account the green-house gas effect. The authors estimate, against the background of global heat balance, the influence of heat release by infra-red radiation, considering also the convective heat transfer to the layers of troposphere and stratosphere as well as how this process is affected by carbon dioxide gas. Such an analysis, to a definite extent, would allow the possible character of future climate changes to be judged.