Scenario planning has formed a growing area of interest on the interface of academia and public and private sector policy-making. While methodological approaches are well covered in the academic literature, less attention has been paid to studying the use, impacts and effectiveness of scenario planning in public policy-making. This article combines preliminary findings from a review of evaluative scenario literature with workshop discussions among scenario practitioners, using environmental relevant policies as a case study. Subject to the nascent evaluative scenario literature, our preliminary findings highlight that scenario planning still is often executed in a rather ad-hoc and isolated manner and is mostly geared towards indirect decision support such as agenda-setting and issue-framing. The slim evidence base aggravates the assessment, but the potential of scenario planning to prepare public policy-making for the uncertainties and surprises of future developments and better manage complex decisions involving conflicting societal interests is clearly not fully utilized. Political and institutional context factors need to be treated with greater care in the future. Making better decisions under conditions of deep uncertainty does not only require rigorous analysis, but also political will and more stable institutional settings and organisational capacities to build up trust and experience with adaptive, flexible process formats. We synthesize our analysis with a discussion of further research needs.