As sustainability shifts from aspiration to enforcement, real-world impact becomes the defining basis for corporate credibility and market access. Traditional sustainability metrics, which were designed for disclosure rather than judgement, no longer meet the demands of investors, regulators, or communities. They describe activities in silos and ignore system-wide consequences, obscuring who is affected, where, and at what cost. These siloed metrics routinely misrepresent risk, mask trade-offs, and undermine accountability, particularly where climate, water, nature, labour, and development challenges intersect. New measurement approaches that reflect interdependence, including system-level and place-based metrics that reveal cumulative pressures, distributional effects, and long-term viability are needed. As finance, trade, and regulation increasingly rely on demonstrable outcomes, organisations that cannot evidence real-world impact face discounting, dispute, or exclusion. In this environment, meaningful metrics are not optional—they determine competitiveness, legitimacy, and resilience.