Technological innovation is key to mitigating climate change, yet excessive faith in technology may undermine the wider societal transformations needed to address it. In their roles as knowledge producers and trusted public figures, scientists play a vital part in shaping how societies understand and respond to climate change. We examine techno-optimism — here defined as the belief that technology will largely solve the problems caused by climate change — among scientists using survey data from $N = 9,199$ scientists across $115$ countries. Our findings show that techno-optimism is most prevalent among scientists in applied and natural sciences, and among those with right-leaning political views. Techno-optimistic scientists are substantially less likely to engage in civic climate action (28\% lower) or make high-impact lifestyle changes (20\% lower). These results suggest that techno-optimistic worldviews within science may inadvertently constrain the behavioral and cultural shifts required for effective climate action. The preprint is available here.