Methodology

This page explains how Eye on Earth chooses and handles the data behind each indicator.

Choosing indicators

We prioritise indicators that are (1) globally significant, (2) measured by a credible scientific body, (3) published openly, and (4) updated regularly. We favour a small number of well-understood measures over a sprawling dashboard.

Sourcing figures

Each figure is taken from a primary or authoritative secondary source — for example NOAA and Scripps for CO₂, the WMO and Copernicus for temperature, NASA and NSIDC for sea level and ice, Ember and IRENA for energy, WRI/Global Forest Watch for forests, WWF/ZSL and IUCN for biodiversity, and UNEP for resources and waste. The specific sources are listed on every indicator page and collected on our data sources page.

Charts

Our charts are drawn directly from published values. Where a chart is stylised or illustrative rather than a precise reproduction of a dataset — such as the surface-warming map on the home page or the composite “analysis” indices — we label it as illustrative. Composite indices are simple normalisations intended to communicate pattern, not to replace the underlying measurements.

Handling uncertainty

Environmental data carries uncertainty. We report central estimates with ranges where the source provides them, flag preliminary figures (for example, current-year temperature rankings), and avoid comparing numbers produced by incompatible accounting methods (for example, different ways of counting the fossil-fuel share of energy).

Updates and corrections

Figures are reviewed periodically and updated as agencies publish revisions. If you spot an error, please contact us and we will correct it.