Our Methodology

Global emissions data

Global CO2 figures are sourced from the IEA World Energy Outlook 2023 and Global Carbon Project 2023. The live counter extrapolates annual totals to a per-second rate (36.8 Gt ÷ 31,536,000 seconds = ~1,167 tonnes/second).

Carbon calculator

Emission factors are taken from DEFRA's GHG Conversion Factors 2023 — the UK government's official figures used by businesses for carbon reporting. All calculations happen in your browser.

Country data

Country-level emissions are from IEA 2023. Per-capita figures divide total national emissions by UN population estimates.

UK city data

UK city footprint estimates are based on BEIS Local Authority CO2 statistics, adjusted for consumption-based emissions.

Limitations

All figures are estimates. Emissions data has a 1–2 year lag. City-level figures involve modelling assumptions. Use these figures for educational purposes and general guidance.