Sustainable development requires understanding both the ecological and socioeconomic dimensions of the interdependence between the climatic system and biodiversity. And coherent and integrated policies and measures should be adopted at all levels to address the critical role of biodiversity. However climate change and biodiversity related issues are addressed in a specific though fragmented manner through two of the three so-called Rio Conventions adopted in 1992, namely the UNFCCC and the CBD. Firstly, this contribution recaps the way each of these UN treaties address climate change and biodiversity related issues in the light of its own objectives and provisions. Secondly, it looks at the efforts made or not in each regime to strengthen the coordination toward more interconnected policies and measures. Thirdly, it hightlights some current challenges to address the need of a better synergistic approach of these issues.