Recent research has described concern and anxiety about climate change, especially among young people, but limited data are available looking at the responses of adolescents. Based on further analysis of an existing dataset that obtained survey responses from young people aged 16-25 in 10 different countries, this paper examines differences associated with gender and age, which are important predictors of vulnerability to the impacts of climate change. Gender differences were small but consistent, with female respondents expressing greater levels of concern and negative emotions, while male respondents were more optimistic and expressed greater faith in the government. Within this narrow age group, there were small but significant positive correlations showing that concern and negative emotions about climate change were higher among older respondents. There were complex differences among countries; in general, respondents in the Philippines, India, and Nigeria reported a stronger psychological impact of climate change than respondents in the United States and Finland. These results help to describe the extent and patterns of climate anxiety in multiple locations around the world in an age range that is relatively understudied.