This doctoral thesis focuses on the foundations of the theological and academic thought of Leonardo Boff. It demonstrates how his theology, in this phase of 1973-77, depends on his experience in the two complex and different realities of Europe and Latin America. The fundamental principle of God’s Kingdom is constructed in the foundational research work, Jesus Christ, Liberator (1972). In this way, an ontological-relational otherness is discovered proceeding from the totality and the interdependence of the life of Jesus. For this reason, the Openess-Dignity-Otherness becomes the answer to the question about full and ultimate meaning present in the social and religious environment lived by Jesus. Although the actual context is different, the human crisis, in which can be observed the paradigm change and global warming, presents a similar question about the total meaning of existence as unity in the diversity of differences. Therefore, this research considers global warming as the boundary signal of the crisis in the ecosystem and on the human that, concomitantly, relativizes sustainable development and trivializes life. For this reason, global warming transforms itself not only in a cry for biodiversity and of the human being against unsustainable development, but also the chance for humanity to rediscover its way to Dignity-Otherness, as much for the human being as for all creation.