Citizen engagement in Citizen Science (CS) means an active involvement of individual citizens in scientific research, policy and program development. However, it should be noted that including stakeholders in CS organisation, planning, decision-making, implementation of activities and evaluation requires adequate technological capacity, the understanding of roles and clear communication. The possibility to engage users in data science together with the power of AI algorithms presents no doubt opportunities for crowd sourced data science and collective intelligence to be brought to bear on fundamental challenges facing humanity like poverty, diseases, famines and developmental challenges. The focus of the interdisciplinary multinational consortium CLIMAS (Horizon Europe project) is research on empowerment of citizen scientist, researchers, civil organizations, SMEs, innovators, and policy makers by offering practical insights for co-creation of collective intelligence, aligning values and build trust between stakeholders. The project is based on idea that Climate Assemblies can be a perfect domain for participating in citizen science projects, with an active contribution of citizens by tackling environmental issues. In this sense, citizens participate in the collection of evidence, but also in the co-creation of new knowledge to increase awareness of climate change and ultimately to drive changes in climate policy.