This report presents the final findings of the HEAT project, which investigated climate-related misinformation, disinformation, and malinformation (MDM) across Germany, France, and the Netherlands—three European Union (EU) member states strategically selected to reflect linguistic, political, and media-system diversity across the EU, as well as distinct disinformation threat profiles. Together, they capture a range of challenges confronting policymakers, civil society, and other actors engaged in climate policy communication. The research shows how false or misleading narratives about climate change are seeded, adapted, and amplified across digital ecosystems, undermining trust in science, policy, and democratic institutions.