This study examines the pace and content of Climate Change Mitigation Technology (CCMT) inventions, focusing on the influence of government-funded research on patent characteristics. Utilizing data from the USPTO, we analyze the trends in CCMT patenting from 1988 to 2017 and reveal a significant increase in CCMT inventions. However, patents in hydrogen technology and Carbon Capture and Storage (CCS) are comparatively low, suggesting these fields are still in the early development stages. CCMT inventions rely heavily on government-funded research, particularly in CCS and hydrogen technology. CCMT inventions relying on government research are more complex and generate larger and more pervasive knowledge spillovers than their counterparts. However, they are less likely to be novel and tend to consolidate rather than destabilize existing technologies. Interestingly, the effect of government research reducing the likelihood of novelty is only observed in CCMT inventions and does not extend to utility patents. These findings highlight the role of government-funded research in facilitating high-quality CCMT inventions through knowledge spillovers. Our study underscores the importance of sustained and targeted public investment in CCMT R&D.