Climate change simulations allow the experience of complex processes in rapid progression. Additionally, they hold the potential to enable citizens to quickly evaluate the impact of measures offered as political options to mitigate climate change. Taking En-roads as a test case, we investigated whether exposure to a web-based climate simulation influences laypersons’ views on effectiveness of such measures with an experiment in Germany (N = 271). High usability ratings ascertained that the simulation can be used by lay-persons without detailed support. In line with this, app usage was effective. Using the climate simulation led to higher self-efficacy with regard to being able to evaluate policies with the help of tools. Moreover, comparisons with the control group suggested that app usage affects beliefs about the impact of specific measures such as CO2 pricing. Taken together, the results suggest that online climate simulations such as En-roads can help inform and empower citizens in the process of mitigation of and adaptation to climate change.