Mapping Marine Protected Area Expansion Opportunities Using Biodiversity Agreement and Low Human Pressure

Marine protected areas (MPAs) remain insufficient to meet global conservation ambitions. We overlaid four biodiversity-prioritization frameworks to map marine conservation priority zones (MCPZs), then intersected them with a published marine-wilderness layer to identify marine ecological expansion zones (MEEZs). The four sources contribute equally to a descriptive agreement score; the wilderness layer indicates low mapped cumulative human impact, not implementation cost. The global mapped MEEZ extent is 10,583,422.69 km2. Within the 101 IHO sea areas used for scenario accounting, MEEZs cover 10,576,936.16 km2 (2.91% of their summed area), and 16.92% overlaps effective 2026 protected-area (PA) polygons. Adding currently unprotected MEEZs to this PA-only baseline would raise coverage from 9.69% to 9.70%, 9.90%, and 12.11% under conservative, moderate, and ambitious scenarios, respectively. The largest absolute additions occur in the South Pacific, Southern, and North Pacific Seas; the largest within-sea percentage-point gains occur in the Beaufort, Chukchi, and Barents Seas. These candidates are a first-stage spatial screen, not a complete pathway to 30% protection; regional ecological, social, and governance assessment remains necessary.