This chapter describes a “second wave” of modifications to the UN system that would further strengthen its capabilities during the latter half of the twenty-first century. It focuses on two major challenges that the UN will be facing during the coming decades: the international regulation of biotechnology, and the global effort to remove excess carbon dioxide from the Earth’s atmosphere. New, CRISPR-based technologies for editing genomes have allowed scientists to make path-breaking innovations, bringing the concept of “designer babies” far closer to realization than ever before. At the same time, the climate crisis has prompted some scientists to propose radical new forms of “solar radiation management” such as artificial clouds or even a space shield to prevent runaway global warming. Effective regulation of such extreme new technologies will require new international instruments over the coming decades, such as a democratically elected World Parliament, a more representative Security Council, and a standing UN army equipped to respond swiftly to emerging crises.