The GEO Data Portal by the United Nations Environment Programme holds more than 400 different variables as statistics or geospatial data sets (maps), covering themes like Freshwater, Population, Forests, Emissions, Climate, Disasters, Health and GDP.

The EEA glossary contains about 1120 English terms (920 unique concepts) with definitions and definition sources, synonyms and links as well as translations into the 23 other EEA languages.

Edie is a free information and communications service for water, waste and environmental professionals around the world. With independent coverage, powerful search facilities, e-mail alerts and discussion forums, edie provides a one-stop-shop for the exchange of specialised information.

The Environmental Sustainability Index measures overall progress towards environmental sustainability in 142 countries. Its scores are based upon a set of 20 core "indicators," each of which combines 2 to 8 variables for a total of 68 variables.

The World Factbook is prepared by the Central Intelligence Agency for the use of US Government officials. It is an annual publication, but selected data and maps are updated periodically during the year. The Factbook is in the public domain.

The Environmental Information Portal of the World Resources Institute. Using the searchable database, users can search for and retrieve over half a century of environmental data by country, region, variable, or year.