Offering financial benefits or creating social pressure by informing people about what others are doing are the most effective strategies to promote climate-friendly behaviors, according to a new study. These approaches are more effective than simply educating people and providing facts about how to shrink their carbon footprint.
The findings come from an analysis of data from more than 430 previous studies of interventions to promote conservation of water, electricity, or other resources; sustainable consumption habits such as buying organic products; recycling; sustainable transportation; and reducing littering.
The previous studies addressed six different types of climate interventions: appeals that urge people to act more sustainably; commitment interventions to get people to set goals or publicly commit to environmentally friendly behavior; educational interventions that provide facts through flyers, videos, energy labels, and the like; feedback that provides information about a person’s own behavior; social comparison that provides information about other people’s behavior; and financial incentives to reward people for sustainable behavior.
In the past, similar analyses have generally addressed only one type of sustainable behavior or one type of intervention. The new study is the most wide-ranging and comprehensive analysis of its type yet conducted.
Overall, interventions to promote climate-friendly behaviors are effective, the researchers report in the journal Proceedings of the National Academy of Sciences. On average, these efforts increase climate-friendly behavior by 12 percentage points compared to what it would have been without the intervention. That’s a relatively small effect, but about on par with interventions to promote health behaviors.
The researchers employed some statistical techniques to correct for the well-known tendency of scientists to publish only positive results, and found that this reduced the estimated effectiveness of climate interventions to 7 percentage points – still evidence that these strategies “are indeed a useful tool for mitigating climate change,” they argue.
An analysis of just the largest, most statistically robust studies suggested these interventions increase climate-friendly behaviors by just 2 percentage points. This means there might be a tradeoff between reach and effectiveness, the researchers say. “Large-scale interventions often target nonvoluntary participants by less direct techniques (e.g., “home energy reports”) while small-scale interventions often target voluntary participants by more direct techniques (e.g., face-to-face interactions),” they write.
Interventions that use social comparison or financial incentives have the largest effects, the researchers found. Interventions that use feedback or education have the smallest effects. And interventions that involve appeals or commitments are somewhere in the middle.
Some behaviors are easier to change than others. “Interventions targeting littering showed by far the strongest effects,” the researchers write. Interventions to promote recycling, resource conservation, or sustainable consumption habits were less effective, but still significantly increased climate-friendly behaviors. Interventions to promote sustainable transportation choices had the smallest effects.
But, the researchers note, behaviors differ in their climate change impact. A smaller increase in a high-impact behavior might have a greater impact on carbon emissions than a larger increase in a lower-impact behavior.
“For example, in terms of climate change mitigation, an increase of 7 percentage points in recycling is not equivalent to an increase of 7 percentage points in sustainable food consumption,” they write. “Even behaviors that are difficult to change might nonetheless have a large impact because even small changes in the behavior can have large effects on the outcome of interest.” How long the behavior change lasts is another important variable that’s not captured by the current analysis.
Future research should look at the effects of combining different interventions, the researchers say. More study of infrequent but high-impact behaviors such as forgoing air travel or installing solar panels is also necessary.
Source: Bergquist M. et al. “Field interventions for climate change mitigation behaviors: A second-order meta-analysis.” Proceedings of the National Academy of Sciences 2023.
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