The green movement was rooted in the 60’s, beginning more than 40 years ago. Spurred on by emerging energy markets and volatile commodity pricing, the cost of energy and the cost of building materials became global issues.As building technologies aggressively adopted air-conditioning and as building design embraced the outdoors with a heavy emphasis on “glass box” configurations, building technology challenged local climates and strove to provide consistent “in-office” environments. Energy costs and operating costs were secondary to this design goal. This philosophy was soon recognized as unsustainable economically and environmentally. The global conservation movement picked up pace in the 80’s and 90’s.As climate change gathered more attention and as energy costs began to again increase, nations sought remedies. At the 1992 United Nations Conference on Environment and Development in Rio de Janiero, concern over greenhouse gases inspired a call for environmental rating systems for new construction projects.While concern over energy and operating costs seemed to fluctuate according to market conditions, the concern for harmful CO2 emissions had a feeling of permanence. International rating systems such as BREAM from the United Kingdom and BEPAC from British Columbia inspired the development of several U.S. rating programs. Specifically, the Austin Energy Green Building System, Green Built North Texas and Built Green Colorado started the ball rolling. These early green rating programs were viewed as regional and lacked criteria for national evaluations.The LEED® Rating System is the product of the U.S. Green Building Council (USGBC). The council’s goal was to develop a new design and construction sustainability rating system. The system was designed to encourage the development and evaluation of economically, environmentally and socially sustainable design and construction principles. Due to its comprehensive systems, the LEED® rating system is now the standard for sustainable achievement throughout the U.S. and most of the world.Other prominent rating systems are:• Green Globes – the system developed by the Green Building Initiative and an offshoot of BREAM.• Energy Star – Developed by the U.S. Environmental Protection Agency and the Department of Energy, this rating system deals primarily with energy efficiency.• NAHB Green Scoring Tool and Green Building Certification – The National home Builder’s guide to green construction.The LEED® rating system includes the concepts of other rating systems and takes a more detailed look at the design and development process as integral parts of an overall evaluation system. The LEED® system has been implemented into many community, state and federal programs.