Credible scientists give us 10 years to be well on our way toward global greenhouse gas (GHG) emissions reductions in order to avoid catastrophic climate change.’ The urgency of the emissions reduction adds significance to the role of embodied impacts. Most current sustainability thinking is informed by the fact that roughly 20 percent of a building’s total environmental impacts are embodied in the materials, with the remaining 80 percent due to operations (Figure 1). However, a frequently overlooked element is that the embodied impacts occur today, while the operations impacts occur over the building’s lifetime. Consider a building built today with a 50 year design life. The solid lines in Figure 2 show that, for at least the first 10 years, the majority of the environmental impacts are due to those embodied in the building, not operations. The dashed lines represent a more energy efficient building, where 60 percent of the total impacts are due to operations; in this case it takes over 30 years for the operations impacts to overtake the embodied impacts.”