Which organization developed a system to certify buildings as "green" in 2000?

The United States Green Building Council (USGBC) developed a system for certifying buildings as "green" through its Leadership in Energy and Environmental Design (LEED) program, introduced in 2000. LEED certification is designed to promote sustainable building practices that focus on energy efficiency, water saving, sustainable site development, material selection, and indoor environmental quality. The framework set by USGBC encourages building owners and operators to pursue strategies that help improve performance across the board.

Other organizations mentioned have various roles in environmental protection and building standards but do not specifically provide a green building certification system as comprehensive or widely recognized as that of the USGBC. For instance, the International Building Council does not exist as a recognized entity responsible for such certifications. Meanwhile, the Environmental Protection Agency (EPA) focuses primarily on regulating pollution and managing environmental standards rather than building certifications. The National Green Building Alliance exists to promote green building practices but does not offer a certification system equivalent to LEED. Therefore, the USGBC distinctly stands out as the organization that initiated and developed a successful system for recognizing environmentally sustainable building practices starting in 2000.