Ciarán is from Dublin, Ireland, and is a member of the Greens/EFA political group. Ciarán sits on the ITRE and TRAN Committees of the European Parliament as a full member, and on the REGI Committee as a substitute member. He serves as President of EUFORES, a European cross-party network that promotes the deployment of renewable energy sources and energy efficiency. He is a trained architect and urban planner, and is currently the Rapporteur for the revision of the Energy Performance of Buildings Directive (EPBD). Prior to his election to the European Parliament in 2019, he served as a Dublin City Councillor, Teachta Dála (TD) for Dún Laoghaire, and Minister of State with responsibility for sustainable transport and climate change.

Julije is the Managing Director of the North-west Croatia Regional Energy Agency, member of the European Covenant of Mayors Board and has been the President of the European Federation of Agencies and Regions for Energy and the Environment - FEDARENE since 2013. From 2020, Julije has served the Office of the Croatian President Zoran Milanović as the Special adviser on Energy and Climate. He has published over 60 scientific and professional papers in journals or presented at mayor European conferences.