- Climate Voices
- Climate Change Action
- Climate Change Action
- Clean Energy Business Council
- Classroom
- Cirencester Science and Technology Society
- Centre for Climate Change Research (CCCR)
- Centre for Climate Change Research (CCCR)
- Centre for Climate Change Research (CCCR)
- Centre for Climate Change Research (CCCR)
- Centre for Climate Change Research (CCCR)
- Central Tibetan Administration
- Central Tibetan Administration
- Center for Large Landscape Conservation
- Center for Climate Strategies
- CCCR - Indian Institute of Tropical Meteorology
- Catherine Donnelly Foundation
- Catalyst
- Catalyst
- Catalyst
- Catalyst