Calling attention to opponents of climate action in climate and health messaging

Previous research suggests that providing information about the health effects of climate change and the health benefits of climate action can increase public engagement with the issue. We sought to extend those findings with an experiment to test the motivational value of calling attention to opponents of climate action. In February, 2022, we conducted a survey experiment with adults from the USA, quota-sampled to represent the USA population (n=2201). Participants were randomly assigned to a no-message control condition, or one of four message conditions identified as authored by concerned health professionals. These messages warned recipients about the negative effects of climate change on health, and either made no mention of an opponent to climate action, or were messages augmented by identifying one of three opponents: (1) fossil fuel chief executive officers and their lobbyists, (2) politicians, or (3) a combination of the two. Portrayal of opponents to climate action increased attitudinal engagement, support for mitigation policies, and intentions to advocate for climate solutions, compared with message conditions not identifying an opponent-with the combined opponent portrayal tending to result in the largest effects; these effects were evident with audiences across political lines, especially political conservatives. Climate and health messages-with or without portrayal of an opponent-also increased trust in the messengers relative to the no-message control. These findings suggest that identifying opponents to climate action can be advantageous to building support for such action, reducing political issue polarisation, and fostering greater trust in health professionals as climate messengers.