Scientific evidence is clear: unsustainable resource use, destruction of nature, and pollution are changing the climate and other critical Earth systems. By damag­ing the Global Commons, humanity has the power to undermine life on earth as we have known it for millennia. Major and rapid transformations of energy, production, and con­sumption systems require data and metrics to guide better poli­cies.

The Global Commons Stewardship (GCS) Index is a composite of the latest breakthroughs in sustainability indicators, focusing attention on how countries are af­fecting the Global Commons both within their borders and through impacts embodied in trade and consumption (so-called “international spillovers”).

The Index aims to inform actions to achieve major international agreements, including the Sustainable Development Goals (SDGs), the Paris Climate Change Agreement, and the Con­vention on Biological Diversity. This Index is the successor to the Pilot GCS Index, which was released at the 2020 Tokyo Forum.

In its inaugural report, the 2021 GCS Index provides scores for 100 entities: 99 countries and the European Union (EU27). The organization of the Index is structured around two major pillars: domestic impacts and international spillovers. There are six impact categories: Aerosols, Greenhouse Gas (GHG) Emissions, Terrestrial Biodiversity Loss, Marine Biodiversity Loss, Nutrient Cycle disruptions, and Water Cycle disruptions. This year’s edition includes 33 indicators using data from official sources and scientific research. Scores and dashboards are presented in proportional terms that allow comparison across countries with very different sizes, usually in per capita units, and also in absolute terms to identify which coun­tries are having the greatest absolute impacts on the Global Commons. Results presented this year are based on data collected largely pre-COVID-19.

The Global Commons Stewardship Index is a collaboration between the SDSN, the Yale Center for Environmental Law & Policy, and the Center for Global Commons at the University of Tokyo. We gratefully acknowledge financial support for the Index from the University of Tokyo.