This chapter debates historical responsibility for climate change. The argument from historical responsibility has a legal dimension, as it is often used to assert the heightened mitigation and compensation obligations of some states. The debate here begins with the question of whether certain historically high-emitting states are legally bound to provide some sort of compensation for past levels of greenhouse gas emissions. Sarah Mason-Case and Julia Dehm answer this question in the affirmative, arguing that international law, but also notions of justice, provide bases for recognizing historical responsibility and for claiming reparation for the wrongs inflicted. Alexander Zahar, on the negative side, attacks the assumption that historical emissions and their growth rate since Industrialization are known accurately enough, such as to allow for blame to be pinned on certain countries and not others.