Access to earth observation data has become critically important for the wellbeing of society. A major impediment to achieving widespread sharing of earth observation data is lack of an operational web-wide system that is transparent and consistent in allowing users to legally access and use the earth observations of others without seeking permission from data contributors or investigating terms of usage on a case-by-case basis. This article explores approaches to supplying a license-based system to overcome this impediment in the context of the Global Earth Observation System of Systems. It discusses the benefits and drawbacks of the explored approaches and suggests an integrated legal and technological approach for supplying an effective web-wide sharing environment for earth observation data.