Enhancing Perceived Effectiveness of Climate Policy to Boost Public Acceptance

Because the successful implementation of climate policies requires public acceptance, it is critical to understand the determinants of policy acceptance and ways to boost it. In this research, we aim to test the causality of the effect of perceived effectiveness on policy acceptance. Further, we examine whether providing people with information about a climate policy’s objective effectiveness can enhance perceived effectiveness and, in turn, the policy’s acceptance. In a preregistered experiment (N = 953; T1), participants were asked about the perceived effectiveness and acceptance of a speed limit on German highways. Beforehand, participants in the information condition were provided with details about the speed limit’s effectiveness in terms of CO2 reductions, whereas participants in the control condition did not receive this information. Participants were asked about their perceived effectiveness and policy acceptance again 1.5 years later (T2; n = 334). We found that providing vs. not providing such information led to higher perceived effectiveness but not greater policy acceptance at T1. However, among those participants without prior knowledge of the speed limit’s effectiveness, providing the information positively affected both perceived effectiveness and policy acceptance at T1. Finally, we found a causal indirect effect of intervention (vs. control) on policy acceptance (at both T1 and T2) via perceived effectiveness at T1. Our results suggest that perceived effectiveness is an integral causal determinant of policy acceptance in the climate domain. Explaining the objective effectiveness of climate policies thus poses a promising approach for policymakers to increase public acceptance of climate policies.