Greenhouse gases such as carbon dioxide, methane and others are believed to have a significant impact on global climate warming. Emissions of carbon-containing gases are commonly referred to as carbon footprint which reflects their formation and emission into the atmosphere in the full production cycle. The questions of definition of emission (carbon footprint) of carbon dioxide at soda ash production are considered. The differences of transit (indirect) and end-to-end emissions are shown. The calculations of through emission (carbon footprint) of soda ash and quicklime production are given. Based on chemical and thermochemical equations analysis and peculiarities of technological processes it was determined that the carbon dioxide net carbon footprint emission in soda ash production is 975 kg/t soda. The end-to-end carbon dioxide emission in lime (calcium oxide) production is 1180 kg/t.