“Net Zero” has been an effective rallying cry for the green building movement, signaling a goal of having every building generate at least as much energy as it uses. Enormous strides have been made in improving the performance of every type of new building, and even more importantly, renovating the vast and energy-inefficient collection of existing buildings in every country. If we can get every building to net-zero energy use in the next few decades, it will be a huge success, but it will not be enough.  
 
In Build Beyond Zero, carbon pi