While the UN officially recognizes only 17 Sustainable Development Goals (SDGs), proposals for "SDG 18" emphasize expanding the agenda to address critical, emerging challenges. The most prominent proposals focus on either incorporating space exploration for long-term human survival or ensuring peace through "No War" initiatives. 
Top Proposals for SDG 18
  • SDG 18: Space Exploration & Sustainability (Space Renaissance): This proposal argues that human long-term survival is at risk if confined to a single planet. It promotes using space-based resources (mining, energy) to relieve Earth's environmental burden, reducing resource wars, and establishing independent communities in the solar system.
  • SDG 18: No War (Peace and Justice): Proposed by peace organizations, this goal aims to strengthen international law and protect civilian populations. It suggests that a dedicated "No War" goal is necessary to prevent war from undermining the other 17 SDGs.
  • SDG 18: Zero Animal Exploitation (Beyond Cruelty Foundation): This campaign urges the UN to add a goal focused on ending animal exploitation, highlighting the need for animal welfare and plant-based systems in sustainable development. 
Core Principles of Proposed SDG 18 (Space/Technology Focus)
  1. Relaunching Global Economy: Using space-based industry to grow the economy beyond the limits of Earth’s environment.
  2. Environmental Protection of Earth: Relieving the ecological strain on Earth by transferring industrial activity into space.
  3. Human Expansion: Developing space communities to ensure humanity's survival against potential disasters (e.g., asteroid impact, nuclear war).
  4. Scientific Advancement: Enhancing understanding of ecosystems through space exploration. 
Why an 18th Goal?
Proponents argue that the 17 SDGs, while comprehensive, were established in 2015 and do not adequately address the rapid advancements in technology or the growing need for global peace and environmental stewardship. They emphasize that the 17 goals are interdependent and require a stronger foundation to be fully realized by 2030. 
Context in the Existing Agenda
Although not currently in the UN's official 2030 Agenda, these proposals reflect the ongoing need to update global goals to meet new realities, such as climate change, pandemics, and the necessity of sustainable space development.