The need to understand how to encourage people to adopt more climate-friendly behaviors is pressing, but "nudging" people to adopt behaviors such as recycling, taking public transport, and reducing their consumption of energy and water, is notoriously difficult. For example, the Behavioral Insights Team failed to find an effect of an advice and support campaign on energy consumption and interventions to reduce single-occupancy cars, and more recently found that the most successful arm of a large trial to reduce household water consumption only reduced it by 0.5%.