Climate change is the most important challenge humankind has ever faced. It is commonly accepted that GHG emissions must be reduced at great pace and to a significant extent to keep global warming below 2 (or, preferably, 1.5) degrees Celsius. This can only be reached if the obligations of major players-States, enterprises and investors-are sufficiently clear. The Oslo Principles aim to discern the legal obligations of States. The current Principles focus on the obligations of enterprises and investors. They identify the reduction obligations of enterprises, and articulate a series of related obligations. Investors can-and many already do-play an important role. These Principles aim to provide a legal basis for active investment management and engagement geared at stimulating enterprises to comply with their legal obligations. An extensive commentary further explains the Principles and their legal underpinning. The members of the expert group are Thomas Pogge, Brian Preston, Tianbao Qin, James Silk, Jaap Spier (reporter), Elisabeth Steiner, Philip Sutherland, and Dani l Witte.