This paper comments on the idea of engineering novel and artificial forms of life to combat anthropogenic climate change by 'terraforming' the Earth. The idea of 'Nature-based Solutions' that sustain biodiversity while supporting human well-being connects conservation and climate change. However, the technologies of synthetic biology, particularly gene-editing, challenge the notion that only naturally-evolved organisms and ecosystems are capable of influencing in climate. The release of geneticallyengineered organisms poses risks to biodiversity. Synthetic biology's engineering vision for the organic world is bold. But , terraforming with synthetic organisms is at odds with the conservationist's concern for living diversity and diverse ecologies.