Introduction As environmental and climate issues permeate all areas of human activity, it is increasingly likely that discussions about these problems and solutions will arise daily in teaching across disciplines. The knowledge of sustainability and climate change among teachers of different education levels is not very systematic, which can hinder the growth of climate awareness in society. The problem Misunderstood or oversimplified concepts about the nature of the problem can lead to erroneous conclusions and practices. In order to design more effective teacher training and better learning materials for both teachers and students, it is important to understand the nature of the misconceptions, what content of scientific explanations is missed or failed to be integrated into one's knowledge system, and which knowledge might be distorted to fit the lay understanding. The study's first aim was to describe the knowledge of the teachers who participated in specially organised interdisciplinary training on the nature of, and adaptation to, climate change. Specifically, teachers' pseudo-, synthetic, and misconceptions about climate change were the focus of the analysis. The study's second aim was to assess the impact of climate awareness training to take the first steps in examining the effectiveness of this increasingly common way of spending resources, which can problematically generate an illusion of knowledge acquisition. Thus, the study assessed how climate-related training impacted the change in knowledge among the trainees. The method The three research questions guiding the study were: 1) How science-based is teachers' understanding of the nature of, and the adaptation to, climate change? 2) How much and what kind of misconceptions characterise teachers' understanding regarding the nature of climate change? 3) Do climate-related misconceptions (their type and frequency) change as a result of the short interdisciplinary course delivered by top experts in the field? The questions posed to the teachers were as follows: • Why does the addition of greenhouse gases warm the global climate? • Please describe the most important actions that you think would help adaptation to climate change. For assessing the understanding of the nature of climate change, five expert knowledge components were distinguished in the science-based answers to this question: • Greenhouse gases absorb heat radiation • Energy is added to the climate system • The extra energy warms the climate • Warming continues until a new energy balance is reached • Greenhouse gases throw the original system out of energetic balance. The results Only some of these components are represented in the teachers' answers. While almost half of the teachers mentioned that the energy added to the system warms the climate, none noted that the warming lasts until a new energy balance is reached. The ontological category or cognitive schema for the emergence of a new energy balance due to the addition of greenhouse gases was missing in the teachers' answers, with only six of them mentioning disturbed energy balance. A lack of understanding of the energy balance process is likely to mean that the dangers of climate change to human society will probably remain unclear to the respondent. This may be why climate topics are undervalued in schools and curricula. An in-depth understanding may make it possible to better assess the current situation and the future. Our second research question revealed reasoning that does not really describe the nature of climate change. The misconceptions included, firstly, the concepts from the wrong ontological category - for example, there were suggestions that climate warming is related to the hole in the ozone layer. Secondly, there were synthetic or pseudo-concepts that demonstrated a simplified understanding of the scientific content - for example, that greenhouse gases create a "film" in the upper layers of the atmosphere. These distorted concepts could result from the oversimplified explanations or metaphorical terms used in science communication, which for the scientist may have scientific content but become common-sensical in the listener's thinking as they focus on some aspect of the metaphor that the scientist did not, in fact, want to emphasise. In the case of the term "adaptation", the clearest gap was understanding the difference between climate change adaptation and climate change mitigation. However, as we do not know whether the respondents might have understood "adaptation" correctly but chose to answer concentrating on how to prevent the need to adapt, we have not labelled this a misconceptualisation. Nevertheless, some of the answers to the open questions indicate that for the respondents, "adaptation" was a new term yet to be filled with content. In conclusion, we found that some core aspects of the relevant knowledge are missing from the teachers' understanding of climate change, and, at the same time, some synthetic and pseudo-conceptual approaches confuse the information on the climate system and climate change. In further teacher training, we need to consider these conclusions in order to enable teachers to discuss, in particular, the missing or misunderstood concepts. Thirdly, we examined the change in knowledge related to the climate change process after a one-day training session on climate change. There was no change in the understanding of the nature of climate change. Several reasons might be contributing to this result. Firstly, before this study, it was not very clear which aspects of climate change knowledge might need the most support, and the training focused equally on all the relevant knowledge. Secondly, especially when learning complex topics, offering learning methods that help the construction of new knowledge is needed. This would enable noticing and becoming aware of one's own misconceptions. However, the premise of such learning is enabling meaningful discussion and construction of knowledge (for example, problem-before-theory-after design). Thirdly, the more complex the topic to be studied and the more numerous the prior misconceptions, the more times should the learner (re)construct new knowledge in their mind before properly grasping the correct approach. The question on adaptation to climate change indicated that the concept of adaptation was generally unfamiliar to many. Thus, the responses addressed climate mitigation instead of adaptation. The focus remained mostly the same both before and after the training. Nevertheless, the training had a statistically significant effect on referring to the concept of adaptation and the adoption of related topics in the answers after the training (e.g., topics of heat, preparedness for climate-related disasters, etc.). Another significant change is that after the training day, the following elements were referred to more frequently: on the individual level - changes to be made in individual life; need for individual awareness and self-education; individual adaptation measures; on the level of systemic changes, there was an increase in mentioning the state and institutional reorganisation in the context of climate change. These changes were statistically significant. It is unclear why the changes in social science knowledge were more significant compared to natural science knowledge. However, based on the theories of concept development, it could be assumed that facts and knowledge related to social life are more directly related to people's everyday practices and as such, are easier to learn. As a rule, this knowledge is also less in conflict with prior knowledge and intuitive conclusions. At the same time, there can be no intuitively correct - if any - understanding of many processes and laws arrived at by natural sciences. Thus, the more effective transferability of social science knowledge compared to natural science knowledge is probably related to experientiality: during the training, heat waves and other changes influencing peoples' lives directly and demonstrating the effects of climate warming were repeatedly discussed. The emergence and further development of this connection may be the reason why, in this case, there has been a statistically significant shift in the answers related to adaptation. Teachers' increased knowledge of climate change leads to greater concern about climate change and, thus, to a greater willingness to act to protect the climate (Seroussi et al., 2019). More accurate and scientifically correct knowledge enables discussions in classrooms on the inevitably complex topic of climate change. As better knowledge is established, more resources and more time can be dedicated to discussions on what can actually be changed. [ABSTRACT FROM AUTHOR]