Climate change is one of the most urgent problems of modern societies. Its consequences will affect human welfare, economic development, political stability, and social justice in many parts of the world. Humans play a prominent role with respect to climate change: They cause the problem by emitting greenhouse gases, they suffer from the consequences, and it is humans who have the capacity and responsibility to address and master the problem. Therefore, it is important to understand how the public perceives climate change and its consequences. Investigating the public perception of climate change will also help to understand if and under what conditions people are willing to engage in mitigative actions. And since climate change is a problem of global dimensions, it is important to compare public perceptions across nations. The present paper presents a cross-national survey that compares climate change perceptions of undergraduate students in economics across five countries: Norway, Finland, Germany, Austria, and Bangladesh (total N = 600). Perceptions of climate change were compared to perceptions of another challenge to modern societies with potential effects on human welfare and economic development: pandemic influenzas. The questionnaire consisted of six parts: a) risk perception of climate change, measured on 12 psychometric scales (e.g., perceived threat, perceived benefits, knowledge, dread, moral concerns), b) risk perception of pandemic influenzas (measured on the same scales), c) perceived causes of climate change (importance rating for 12 causes, e.g., car driving, destruction of tropical forests, ozone hole), d) perceived consequences of climate change (likelihood of 11 consequences, e.g., food shortages, diseases, climate refugees, species extinction), e) perceived efficiency of various mitigative actions (rating for 11 actions, e.g., taxes on fossil fuels, fertilizing oceans, emission trading, replacing fossil fuels with nuclear energy), and f) support for the same list of mitigative actions (rating). // Two main questions were addressed in the data analysis: a) How do people perceive the risks from climate change compared to those from pandemic influenzas? b) What is the relationship between knowledge of causes and consequences, perceived risk, perceived efficiency of mitigative actions, and policy support for mitigative actions? // Furthermore, differences between nations were analyzed for both research questions. With respect to risk perception for climate change, human causation is generally very salient, and the consequences seem more threatening to humans in general than personally. Pandemic influenzas, in contrast, are seen as less anthropogenic and the consequences seem more relevant personally. Bangladesh deviates from the other countries in that Bangladesh respondents see climate change as more threatening and less controllable. There is little variation across countries with respect to the relationships between variables. Risk perception is related with knowledge about consequences; policy support, in contrast, is more strongly related to the perceived causes and to whether the actions are seen as efficient in mitigating the causes. This implies that people support preventive actions more than adaptive strategies. In addition, we find that misconceptions which have been found in previous research still prevail in our study (e.g., the ozone hole is seen as an important cause of climate change); and that some mitigative actions that are discussed in the scientific debate as potential solutions are neither perceived as efficient nor supported by the public (e.g., fertilizing oceans, putting dust into the atmosphere). The fact that national differences are more pronounced in risk perception than in the correlational structure of the variables may suggest that even though people differ in their perceived vulnerability, the general process of risk perception and evaluation is universal across cultures.