Thirty-by-thirty (30—30) refers to efforts by the global community to conserve 30 percent of terrestrial and marine habitat by 2030. The movement started with calls for setting aside portions of the globe as protected, and became official policy in the USA in 2021. At its heart, the 30—30 initiative is about protecting biodiversity, under threat from habitat loss, habitat fragmentation, climate change, and other factors. This protection can be achieved by creating a network of protected areas, which provide the critical component of connectivity. In this paper the attempt is checked whether the mummificated United Nations trusteeship systemUnited Nations Trusteeship System (UN Charter XII) could get reactivated for the 30 × 30 goal and if the international Anti-Covid-Regimes of the last years can provide insights. The recent literature is reviewed what cooperation and what priority on scientific advice Covid in the end made possible on the international level. The evaluation of the post-war United Nations Trusteeship SystemUnited Nations Trusteeship System reveals limits and scope of that measure of international politics (171 words).