We overestimate the effect of small gestures for the climate

People misjudge the climate effectiveness of their own behaviour. This emerges from a University of Geneva study published in the journal Nature Sustainability.

The research involved nearly three thousand participants, asked to estimate the reduction in CO2 emissions achievable through 32 everyday and consumption actions. Comparing the estimates with the real values reveals systematic errors in both directions.

Some gestures are overrated. Among them are sorting waste, avoiding plastic packaging, reducing hot water use and saving paper when printing. Their reduction potential is low to modest, yet they are perceived as highly effective.

Others are underrated. These are giving up air travel, a vegetarian diet, cutting beef consumption and switching to electric vehicles.

Two mechanisms of distortion

The researcher Mario Herberz identifies two causes.

The first is the availability heuristic. The more an action appears in the media or is taught at school, the more readily it comes to mind, and the more effective people judge it to be.

The second is motivated reasoning. People tend to regard the actions they already perform as more effective, because this reinforces a positive image of themselves.

The study also points to two profiles. Those with strong ecological values tend towards optimism and generally overestimate the impact of environmental actions. Those comfortable with numbers give more accurate estimates and are less affected by these distortions.

The researchers tested various corrective interventions, with effectiveness varying by group, particularly those using the cost of a behaviour as an indicator of its impact. The conclusion is that awareness campaigns should be adapted to different population profiles, in order to encourage the behaviours and policies that genuinely reduce emissions.