Semantic Web for Earth and Environmental Terminology
Modular ontology suite with ~6,000 concepts in ~200 ontologies covering Earth system science.
Visit WebsiteBrowse the tree, filter it, or click any class to see just its corner of it.
Where this one tends to earn its keep.
Earth science data discovery and search
Climate research data integration
Oceanographic data annotation
Geological survey data classification
I haven't checked this label against the actual licence text — it's the catalogue's original guess. Check the ontology's own site before you rely on it.
Others worth a look in Agriculture & Environment.