Ultimately and increasingly, humans are responsible for and to Earth as planet and biosphere. Peoples in their nations are and ought to be united on one Earth, with an ethics inclusive of both humans and nature. Only people can be ethical, but this does not mean that only people count in ethics; on the contrary, we are fully human only when we appropriately respect life on earth in its rich biodiversity. Much of the urgency for conserving biodiversity arises from our duties to other humans, as nature is instrumental to what humans have at stake in their environments. These interests directly feed into national interests and require international cooperation. But a deeper environmental ethics recognizes intrinsic values in and duties directly to nature. Such duties arise because values are distributed at the levels of animals, living organisms, endangered species, and ecosystems as biotic communities, as well as in human life. Sustaining the biosphere underlies and takes priority over sustaining development. This demands an Earth ethics – increasingly an important mission of the United Nations.