The recent IPCC report (IPCC, 2023) highlighted the need to increase the perception of risk and prompt climate action through education. The question is what contribution science and environmental education can make-if any-to this challenge. Psychological research has suggested that knowledge (topical and epistemological) and beliefs about self-efficacy are relevant starting points, but the evidence is scarce and inconsistent. We conducted a transversal correlational study to test the direct and indirect effects of system knowledge of climate change, personal engagement with science, and trust in climate science on the willingness to mitigate the effects of climate change. The participants were 386 students attending high schools in Chile. The results reveal that there is no direct effect of climate change system knowledge on the willingness to act. We did find indirect effects of system knowledge on the willingness to act, mediated by personal engagement with science and trust in climate science knowledge. The results also demonstrate a direct effect of personal engagement with science, and an indirect effect mediated by trust in science. The implications for science education are discussed.