It is widely recognized that changes are occurring to the earth's climate and, further, that these changes threaten important human interests. This raises the question of who should bear the burdens of addressing global climate change. This paper aims to provide an answer to this question. To do so it focuses on the principle that those who cause the problem are morally responsible for solving it (the ‘polluter pays’ principle). It argues that while this has considerable appeal it cannot provide a complete account of who should bear the burdens of global climate change. It proposes three ways in which this principle needs to be supplemented, and compares the resulting moral theory with the principle of ‘common but differentiated responsibility’.