Building sector has a heavy role to create sustainable society, because CO_2 emissions associated with construction and operation of buildings are estimated to be 1/3 of the whole CO_2 emissions in Japan. These CO_2 emissions were estimated from 1970 through 2050 and the following results were obtained. (1) CO_2 emission between 2008 and 2012 will increase by 15% than 1990 level. (2) CO_2 emission can be reduced by 6% between 2008 and 2012, and reduced by 40% in 2050, if the 30% energy saving, long life and environment-conscious materials are adopted to new buildings.
