Does climate change create conditions in which ethnic groups, particularly in developing countries, become more likely to struggle for scarce resources which can then spur ethnically motivated violence and serious atrocities? Or is the relation between climate change and atrocities, if there is one, far more complex and perhaps indirect? How should climate change be viewed as a risk factor for the onset of violent ethnic conflict? What practical relevance could climate change effects have on early warning and prevention of serious human rights violations including crimes against humanity and genocide? The author first considers whether climate change science warnings deserve to be taken seriously before reviewing empirical studies focussing on the supposed link between climate change and ethnic conflict. Second, he argues that it is valuable to treat climate change as a possible risk factor for ethnic conflict situations in which crimes against humanity or genocide might be perpetrated, and to reflect upon early warning and prevention in this connection. The author then sets out five considerations that research on the question of a causal link between climate change and ethnic conflict should take into account.