Support or opposition for policies can be determined both by social motives and by (possibly misinformed) reasoning about them. For example, carbon pricing is often promoted as a key climate policy by economists, but remains relatively unpopular among the general public. In this study, we conduct an online survey experiment with a representative sample of U.S. adults (N = 2,685) to investigate the causal impact of social norms and economic reasoning on public support for carbon pricing. Using exogenously assigned video interventions that embed norm information or policy explanation, we show that, immediately after exposure, both types of information increase support for carbon pricing by around 5 percentage points. A follow-up survey more than 4 months later reveals that this initial increase fades away, but that a combined norm and policy explanation intervention retains a significant negative effect on the share of individuals who strongly oppose carbon pricing. Interestingly, we observe no initial effects on incentivized environmental donations, and a significant decrease in (large) donations in the follow-up. One-shot interventions like ours may thus constitute a first step in overcoming public resistance, but struggle to foster persistent engagement.