For the first time in history, the world has formally agreed to protect nearly half the planet. In September 2025, the United Nations ratified the high seas treaty, officially known as the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement—a landmark global pact to safeguard the parts of the ocean that lie beyond any one country's national jurisdiction.

These vast waters—the high seas—cover nearly half of Earth's surface and sustain much of the life on our planet. Yet until now, they've been largely ungoverned, leaving marine ecosystems vulnerable to overfishing, pollution, and the growing impacts of climate change. In this episode of "After the Fact," Pew's director of ocean governance, Liz Karan, explains why this moment represents one of the most significant conservation milestones in decades—and what comes next.