Cornerstone EEIO is an open, global, environmentally extended input-output (EEIO) model for estimating the greenhouse gas emissions of economic activity. It continues and replaces two widely used models: CEDA, known for its global coverage, and USEEIO, known for its detailed US data. Together they form one model covering 148 countries, 21 regional averages plus one global average, and 405 sectors, free to use.

This release brings three main changes.

- The US model now uses annual detailed IO tables and facility-reported emissions data.

- Data for the European Union, the UK, and China is more recent, reflecting structural changes in the world’s largest economies.

- A consistent time series from 2017 separates real decarbonization from changes in methodology, so year-over-year differences can be used to track progress.

Cornerstone EEIO 2026 emission factors are being released in two phases. The release candidate (2026-rc) is available to download now. Cornerstone EEIO 2026, the final model with the full time series, follows in December 2026 and is intended for measurement and reporting.

Additional support and data insights are available through Watershed’s enterprise offering here.

Read the full methodology and documentation here.