Climate change is an urgent global challenge that affects both environmental sustainability and psychological well-being, making it essential to identify effective ways to promote public engagement in climate action. A growing body of laboratory research suggests that joint action interventions can increase climate action. This study examined whether participation in a real-world joint action task would increase general climate action intention more strongly than an active control condition, and whether this effect could be explained by society-level collective agency beliefs and eco-anxiety. 

In a randomized field experiment, participants were assigned to either a collaborative litter-picking activity or a discussion-based group walk about littering and climate change. Pre- and post-intervention survey data from n = 54 participants were analyzed using measures of climate action intention, collective agency, and eco-anxiety. Results showed that climate action intention did not increase significantly in the joint action condition compared to the active control condition. In addition, neither collective agency nor eco-anxiety mediated the relationship between condition and post-intervention climate action intention. 

These findings sharpen the focus on a central challenge in developing reliable real-world joint action interventions: changes targeted by small-scale interventions may be difficult to translate into broader societal beliefs and more general climate action intentions. The results highlight the importance of testing climate interventions under ecologically valid conditions and understanding the underlying psychological mechanisms of pro-environmental behavior. Future research may use larger samples, more proximal behavioral outcomes, and measures towards different levels of beliefs.