This book makes an argument for the legal role and responsibility of sovereign states in the trusteeship of the Earth. In 1972, the first photo of the Earth – Blue Marble – sparked the imagination and need to care for our planet. In the same year, the world’s first UN conference on the environment adopted the Stockholm Declaration, proclaiming that the Earth’s natural resources and ecosystems 'must be safeguarded for the benefit of present and future generations'. Today, the Earth’s ecological systems deteriorate at accelerating speeds, as if Earth does not matter to law and governance. But what if it does? Earth system science and related jurisprudence provide clear guidance for effective law and governance, in particular the trusteeship responsibilities of sovereign states. This book closes the gap between the promises of international environmental agreements and the concept of state sovereignty. Maintaining that state sovereignty is not an end in itself, but rather a means to