The media is brimming with images of polar ice caps melting, sea levels rising, and statistics showing the earth's temperature steadily increasing. These hallmark images and statistics of climate change are often accompanied by scientists discussing the cause of these changes and how to address them. Although not unanimous, most scientists place the blame for climate change squarely on human action, and specifically on greenhouse gas (GHG) emissions. For this majority, the logical manner for addressing climate change is by altering human behavior to reduce GHG emissions. With scientific evidence and popular support on their side, state and local lawmakers throughout the United States have taken it upon themselves to reduce GHG emissions. Over the past few years, the attention of state and local lawmakers to climate change has led to the proliferation of various laws regulating GHG emissions (both directly and indirectly). This state and local action has come despite what some consider the federal government's failure to address climate change on the national level. As one of the major sources of GHG emissions, buildings have received much of the state and local regulatory focus. This focus on buildings is driven by statistics showing that buildings consume 39% of all energy in the United States and 72% of the nation's electricity, while producing 39% of GHG emissions. 4 According to the numbers, buildings are responsible for more GHG emissions than either industry or transportation. The statistics also show a continual increase in the level of GHG emissions from buildings. Although new laws regulating buildings vary widely, they typically apply green building standards to new construction and substantial renovations. Generally speaking, early enactments addressed public sector buildings through green building mandates and private sector buildings through green building incentives. Since the early enactments, new regulations have become increasingly broad, including mandates by several local governments applying green standards to private sector buildings. Based on current trends and the political atmosphere surrounding climate change issues, the application of mandatory green building standards to the private sector will not only continue, but may eventually encompass existing private sector buildings. Although the trend toward regulating private sector buildings is clear, the origin of future regulations is still an open question. While states and local governments took an early lead in addressing climate change, the future bodes well for regional pacts and perhaps national regulation from the federal government.