What matters from the standpoint of justice is whether people's important human interests are protected and promoted, not the volume of emissions they produce.

Second, it is worth asking why we should care about emissions at all. In themselves they do not matter to the people who generate them or who enjoy the goods and services whose production involves greenhouse gas emissions. They matter because they are a by-product of activities that people engage in to serve important human interests. More specifically they largely arise because of energy use (for building, heating, cooling, transporting, manufacturing, lighting and so on) and because of agricul