Abstract
Net-zero-energy buildings (ZEBs) that contribute to making annual energy consumption balances zero are effective measures for reducing greenhouse gas (GHG) emissions in the construction sector. As the application of ZEBs progresses, GHG emissions during the construction of buildings and the manufacturing of materials and products (called construction EG) account for a relatively large proportion of overall emissions. This study aimed to clarify construction EG as a means by which to formulate policies for the reduction of emissions in each country. The construction EGs of 43 countries from 2011 were analyzed. The 56-sector input/output table and CO2 emission data of the 2016 World Input/Output Database, published by the EU, were both used in this analysis. It was found that the construction sector accounted for the highest proportion of total CO2 emissions. Moreover, the fraction of construction EG tended to be higher in developing countries such as China and India, while developed countries tended to contribute a lower fraction of construction EG. Construction EGs were shown to be heavily influenced by the sectors that manufacture “cement”, “steel bars and steel frames”, and “energy sources”. Thus, it is very important to advance technological developments to reduce CO2 emissions within these sectors. The annual variation of construction EGs and CO2 emissions from 2000 to 2014 showed that the construction EGs and total CO2 emissions in developing countries were increasing, whereas emissions from developed countries have been decreasing slightly.