Abstract
<title>Abstract</title> <p>Background Climate change has emerged as one of the greatest global public health threats of the twenty-first century, with profound consequences for disease patterns, food security, mental health, and healthcare delivery. As frontline healthcare professionals, nurses play a critical role in addressing climate-related health challenges. However, evidence suggests that many nurses remain inadequately prepared to respond effectively. This study assessed nurses' knowledge of climate change and its health impacts in selected healthcare institutions in Southwestern Nigeria. Methods A convergent parallel mixed-methods design was employed among registered nurses working in six selected tertiary and secondary healthcare institutions in Ekiti State, Nigeria. Quantitative data were collected using a structured questionnaire adapted from validated instruments, while qualitative data were obtained through face-to-face interviews. A total of 396 nurses participated in the quantitative survey. Descriptive and inferential statistics were performed using SPSS version 26, while qualitative data were analysed thematically using NVivo software. Results The findings revealed that 61.4% of nurses demonstrated good knowledge of climate change and its health impacts. Most participants correctly identified climate change definitions, anthropogenic causes, and its links with vector-borne diseases, mental health disorders, and water-borne illnesses. Nevertheless, important knowledge gaps were identified, particularly regarding indirect effects such as malnutrition and food insecurity. Nurses in tertiary healthcare institutions were significantly more likely to possess good knowledge than those in secondary facilities (AOR = 0.300; 95% CI: 0.186–0.484; p < 0.001). Qualitative findings further showed that knowledge was largely acquired through self-learning, social media, and clinical experience rather than formal professional training. Conclusion Although nurses in Southwestern Nigeria demonstrated encouraging levels of climate-health knowledge, significant gaps and institutional disparities remain. Integrating climate-health education into nursing curricula and continuing professional development programmes is essential for strengthening nurses' preparedness and promoting climate-resilient healthcare systems.</p>