Recent international climate agreements ask for an acceleration of innovation in climate change mitigation technologies (CCMTs). To design and plan efficient and effective actions, evidence is needed on what has been achieved up to now in terms of technological development. This paper provides an objective and evidence-based overview of the status of global inventiveness in CCMTs. Thanks to a detailed methodological approach, able to capture and exploit the information potential of patent data, this paper proposes a comprehensive analysis to evaluate the global inventive activity. Several indicators are defined and used to measure trajectories of technology development, globalisation of inventions, and networks of collaborations. The study focuses on four major international economies: Europe, China, Japan and USA. Findings show that these major economies have substantially advanced their inventive activity, but continuous and common effort is needed to combat climate change. In particular, the emergence of China as a major economy has been very relevant, since it has opened important market opportunities for incumbent players, but has also introduced competitive restrictions. The degree of internationalisation of CCMT-related activity has increased, as well as the number of collaborations among countries. The comparative analysis of two renewable technologies, solar PV and wind, shows that international inventiveness is technology-dependent and reflects country specialisation. Based on this evidence, international climate agreements need to be further supported to foster clean energy innovation, thereby shaping international collaboration and boosting positive competition.