The release of Greenhouse Gases (GHGs) by the activities of humans is a major contributor to current global climate change. A major environmental catastrophe caused by this climate change will be averted only if the emission of GHGs are drastically reduced. Attempts have been made to reach international agreements among nations to achieve this, but these attempts, of which the Paris Agreement is the most recent, appear to be inadequate and ineffective. A group of scholars, the Oslo group, therefore asked the question whether more comprehensive obligations that bind states and enterprises could be deduced from other sources of law. The attempts to answer these questions have culminated in the Oslo Principles on Global Climate Change Obligations. The basic methodology that was followed in drafting the Oslo Principles is described. The Oslo group concluded that several concrete obligations to mitigate climate change could be stated by reference to international and domestic law. Particular attention is given in this contribution to tort law as a basis for mitigation obligations in the Oslo Principles but some attention is also given to other areas of law. The central pillar of the Oslo Principles is the primary mitigation obligation, which according to the Principles, is imposed on states. The ambit and nature of this obligation are described. Finally, it is acknowledged that the Oslo Principles only describe rudimentary obligations on enterprises and that it is both difficult and necessary to set out mitigation obligations that can be imposed on enterprises. The contribution finally proposes that the ideas behind the Oslo Principles and United Nations Guiding Principles on Business and Human Rights can be utilised in devising basic mitigation obligations for enterprises.