Аннотация:The series of monthly mean concentrations of carbon dioxide (CO2)in the near-surface layer of the atmosphere over the past 50 years have beenanalyzed. The series are presented on two publicly accessible Internet resources,namely, the websites of the World Greenhouse Gas Data Center (GlobalAtmosphere Watch, World Meteorological Organization) and of the Earth SystemResearch Laboratory (National Oceanic and Atmospheric Administration, USA).The series from 80 stations are considered, of which 27 are from global(background) stations and the rest are from regional stations. Long-term changesare characterized by the series of twelve-month running averages, while intraannual(inter-monthly) variability is described by the difference of the initialseries and the series characterizing long-term changes. Consideration ofsystematic differences showed that the highest levels of CO2 are characteristic ofthe regions with developed economies located in North America, Western andCentral Europe, and Southeast Asia. Long-term changes (trends) at all stationsare practically identical to those at the global (background) stations. Intra-annualvariability is regular (seasonal). Seasonal deviations from the line of long-termtrends at different points of geographical space demonstrate high correlativesimilarity after respective seasonal time shifts have been applied. Such similarityis manifested even at the long distance between the stations. The root-mean-squarevalues of the series of intra-annual deviations are maximum in the regions withdeveloped economies located in North America and Western and Central Europe.They are smaller in the high latitudes of the Northern Hemisphere, while in theSouthern Hemisphere they are noticeably smaller and decrease with latitude.