He has been trained as a palaeobiologist and palaeoclimatologist, but nowadays he is working on climate and biological systems spanning from the present to the future and all the way to the deep past. He is drawn towards complex system theories and networks and is also interested in socio-ecological systems that humans form together with the surrounding world. He is a founding member of BIOS, and in the core team of the Scientific Consensus on Maintaining Humanity's Life Support Systems in the 21st Century. He is also Chair of the iCCB, integrative Climate Change Biology, together with Jason Head), part of the ETE programme, and an Associate Coordinator for the NOW database.