Education for Sustainable Development (ESD) aims to transform lifestyles and societal structures for a better future. Today, ESD often focuses on climate change (CC) and is widely considered as an important tool for empowering individuals for climate change adaptation (CCA). However, the effectiveness of ESD has scarcely been assessed empirically, especially in non-formal education. To address this gap, we conducted a Delphi study involving ESD practitioners from German non-formal education institutions. Our findings indicate that practitioners recognise the importance of ESD but think that it lacks coherence and needs further development, particularly in teaching CCA. Respondents identified various challenges, including the complexity of the topic and its association with 'dystopian' future visions. For successful CCA, respondents consider the ability to act, self-efficacy and motivation as crucial. We conclude that prioritising problem-solving skills and encouraging learners to reimagine social structures are essential for ESD to effectively contribute to society's CCA preparedness.