Global Commons Stewardship Index

Sustainable management of the Global Commons– the climate system, ozone layer, land biosphere, oceans, and ice sheets & glaciers – requires data and metrics to guide better poli­cies. To this end, the 2021 Global Commons Stewardship (GCS) Index assesses both countries’ domestic impacts on the Global Commons and the impacts embodied in trade and consumption (so-called “international spillovers”). 

The Yale Center for Environmental Law & Policy (YCELP) has partnered with the University of Tokyo Center for Global Commons (CGC) and Sustainable Development Solutions Network (SDSN) to produce the 2021 GCS Index.

The 2021 GCS Index provides scores for 100 entities: 99 countries and the European Union.  There are six impact categories: Aerosols, Greenhouse Gas 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. 

This year’s GCS Index generates five key findings:

  1. Major transformations are urgently needed in all countries to address negative impacts on the Global Commons generated by unsustainable production and consumption.

  2. Rich countries generate the largest share of the international spillovers that need to be addressed. 

  3. Further efforts will be needed to decouple socio-economic progress from the neg­ative impacts of the current trading system on the Global Commons.

  4. G20 countries bear a special responsibility in reforming the governance of the Global Commons.

  5. Persistent data gaps and limitations should be addressed for more real-time and forward-looking monitoring of countries’ impacts on the Global Commons.

The GCS Index aims to inform policymaking to reduce negative impacts on the Global Commons and to accelerate the implementation of the Paris Climate Change Agreement and the Sustainable Development Goals, adopted by all UN Member States in 2015. 

Contact: Reed Miller, YCELP Postdoctoral Associate,

Related resources:

2021 GCS Index

2020 Pilot GCS Index