Environmental Impact of Construction

Buildings consume 70% of the electricity load in the U.S.
[U.S. Green Building Council (USGBC)]
The most significant factor contributing to CO2 emissions from buildings is their use of electricity.  Commercial and residential buildings are tremendous users of electricity, accounting for more than 70% of electricity use in the U.S.

Buildings account for 38% of CO2 emissions in the U.S. (USGBC)
The commercial and residential building sector accounts for 38% of CO2 emissions in the U.S. per year, more than any other sector.

Green buildings provide abundant opportunities for saving energy and mitigating CO2 emissions  (USGBC)
Building green can reduce CO2 emissions while improving the bottom line through energy and other savings.

Waste
The EPA estimates that 136 million tons of building-related construction and demolition (C&D) debris was generated in the U.S. in a single year.
(U.S. EPA Characterization of Construction and Demolition Debris in the United States, 1997 Update.)

Compare that to 209.7 million tons of municipal solid waste generated in the same year.
(U.S. EPA Characterization of Municipal Solid Waste in the United States, 1997 Update.  Report No. EPA530-R-98-007.)

Materials
Construction and demolition waste constitutes 40% of the total solid waste stream in the U.S.
(U.S. EPA "What's in a Building", 1999.)