Concrete's thermal mass can realise fabric energy storage (FES) solutions for improving the energy efficiency of buildings and so reduce their carbon emissions. Concrete offers a free thermal sink that absorbs heat during the day and can be cooled during the night. Steel conducts heat rather than absorbs.
Typically, using concrete's FES can result in internal temperatures being some 8°C cooler than peak external summertime temperatures without the need for energy demanding air conditioning.
Timber has significantly less thermal efficiency than concrete.