In the absence of concerted federal leadership, cities and states have been taking the lead in addressing the issue of climate change. But now, with the help of the American Institute of Architects (AIA), the federal government is stepping up to the plate. The day after his State of the Union speech in January, President Bush signed Executive Order 13423, which mandates green building targets for all executive branch agencies. Topping a long list of goals, it calls for a 3 percent annual reduction in energy intensity, defined as energy consumption per square foot of building space, and increased use