Individual behaviour change is fast becoming a kind of "holy grail" to tackle climate change, in environmental policy, the environmental movement and academic literature. This is contested by those who claim that social structures are the main problem and who advocate collective social action. The objective of the research presented in this paper is to better understand why environmentally concerned citizens choose one of these two types of engagement. Our focus is on the role of experiences of and/or convictions about power in shaping this choice. Within the framework of an explorative qualitative study, we engaged in in-depth interviews with 12 young environmentally concerned citizens. On this basis, five main findings are elaborated. Firstly, powerlessness is shown to be a crucial experience, whatever the respondents' engagement. Secondly, "strategy scepticism" seems to be a more important obstacle for engagement than "climate scepticism". Thirdly, many respondents express significant resistance towards being "conditioned" by awareness-raising campaigns. Fourthly, a "gap" is observed between respondents' analysis and their strategy proposals. Finally, we underscore another important gap between concrete and abstract levels in respondents' discourses. All these findings disclose paradoxical aspects of the role of power in shaping the concerned citizens' engaged choices. (Contains 8 notes.)