Testing deontological warm glow motivation for carbon abatements

•An experiment tests contributions to carbon abatements in groups of three.•In target rounds, contributions are completely crowded-out by the experimenter.•Participants first play three no-target rounds, then six target rounds.•Contributions decline in target rounds, but are positive and relatively stable.•A substantial part of warm glow motivation is independent of marginal climate effects.

Do people contribute to CO2 abatements even when these contributions are completely crowded out by a third party? This study reports from an experimental test of contributions to carbon abatements when the contributions are completely crowded out by the experimenter. Contributions are determined to decline by 44% compared to a policy in which the contributions are spent directly on carbon abatements. Still, contributions remain at 18% of endowments and are relatively stable over six rounds of the crowding-out policy. These results support previous psychological findings that a deontological warm glow is important for motivating environmentally friendly behavior.