This think piece examines the concept of solidarity and contemplates the extent to which it is a relevant and valuable mechanism for the promotion of justice within climate change law. In particular, it is suggested that solidarity potentially offers greater depth and maturity than principles such as cooperation, which have previously been the focus of attention, thereby better reflecting the diversity and complexity of our international society. The climate change framework already features solidaristic measures in the form of the principle of ‘common but differentiated responsibilities’, flexible mechanisms such as the ‘clean development mechanism’, and the introduction of funding initiatives. It is concluded that whilst solidarity is a mechanism which demonstrates potential for further promoting justice within international climate change law, there remains considerable scope for further development in this area.