- EARTh terminological content is derived from various multilingual and monolingual sources of controlled environmental terminology:
- GEMET - GEneral Multilingual Environmental Thesaurus EnvDev,
- the Terminological Bulletin for the Rio de Janeiro Conference on Environment and Development
- IPPC glossaries
- UNEP EnVoc
- Italian Earth Sciences Thesaurus
plus other thesauri and documents concerning specific sectors like inland waters, pollution and climate changes, environmental safety and disasters management, etc.. The selection, as well as the semantic and morphological processing of this terminology, is still in progress, and requires the management of problems connected with the utilization of multiple sources, developed in different operational fields and characterized by different approaches, concerning conceptual structuring and terminological representation.