CO2 emission from the construction of buildings is seldom taken into account because focus is primarily on building operation. New technologies have therefore mainly been developed to reduce the energy consumption connected to operation. Super-light technology is a new structural principle giving rise to a substantial reduction of the CO2 emission in the construction phase. The present paper describes how the CO2 emission is reduced when using Super-light technology instead of traditional structural components. Estimations of the CO2 emissions from a number of projects using various construction methods suggest that building with Super-light structures may cut the CO2 emission in half, compared to traditional concrete structures, and reduce it to 25% compared to traditional steel structures.