Climate change denial is associated with diminished sensitivity in internalizing environmental externalities

espite a strong scientific consensus about the existence of anthropogenic climate change, widespread scepticism in the general population continues to exist. Past research has largely relied on self-reported behaviours or behavioural intentions when investigating downstream ‘behavioural’ consequences of climate change denial. As a consequence, there remains a large gap in the literature about how belief in climate change interacts with the pursuit of self-interested, environmentally harmful behaviours. To fill that gap, the present research uses a novel, experimental economic paradigm that allows to attach true environmental consequences to laboratory decisions. Based on ∼56 000 pollution decisions from 2273 participants in more than 30 countries, we find that belief in climate change meaningfully affects decision-making. Our results show that climate change scepticism predicts self-interested choices and showcases that sceptics have an insensitive acceptance of emissions, reaping benefits no matter how large the climate cost are or how small the personal benefits become. Therefore, our results critically augment meta-analytic evidence arguing that downstream behavioural consequences are small to medium in their effect size. We discuss the use of experimental economic paradigms as a crucial innovation tool for psychological research addressing people’s willingness to engage in climate action.