The Effective Impact of Behavioral Shifts in Energy, Transport, and Food

Working Paper

This Working Paper is part of The Living Lab for Equitable Climate Action within Climate, Economics and Finance. Reach out to Mindy Hernandez for more information.

This working paper is the first to analyze which individual behavior shifts have the largest "effective impact" on reducing greenhouse gas (GHG) emissions. Effective impact is a novel measure that combines both theoretical potential (what could happen if everyone adopted sustainable behaviors) and real-world results (what actually happens when interventions aimed only at individuals are attempted without changing the broader system).

While sustainable behavior shifts could theoretically cancel out all the GHG emissions an average person produces each year, individual-level interventions typically achieve only 10% of this potential - highlighting the need for both individual and systemic change. In addition, this paper identifies which behavior change tools (like defaults, social norms or providing information) are the most effective.

Summary

The working paper provides an analysis of the most impactful choices individuals can make to curb GHG emissions. It bridges for the first time two previously disconnected research domains: studies estimating the theoretical emissions reductions possible through behavior change and studies evaluating the effectiveness of individual-level behavior change interventions.

Merging these two literatures, the working paper quantifies the actual emissions reductions that can realistically be achieved through individual-level behavior change interventions. Combining data on projected emissions reductions with evidence on the effectiveness of real-world interventions (representing over 1.3 million individuals), it provides an evidence-based assessment of which behavior shifts offer the greatest emissions-reduction potential when accounting for both theoretical potential and real-world feasibility.

Specifically focusing on behavior shifts in the energy, transportation and food sectors, the paper identifies four key "Priority Shifts" for policymakers, industry and individuals to prioritize.

It also analyzes the effectiveness of various behavior change intervention tools (such as defaults, social norms and providing information), categorizing them and ranking their proven impact.

Key Findings:

We find that behavioral interventions aimed at individuals show consistent but modest effects, typically improving target behaviors by 10 percentage points compared to controls.

We identify four "Priority Shifts" that have a particularly high projected impact on emissions, noting that these are especially relevant for higher-income, higher-consuming populations which have a bigger responsibility to reduce their emissions. In order of climate impact, these behaviors are:

1. Shifting to sustainable ground travel (such as by decreasing gas-powered car use, using public transport and cycling).
2. Shifting to air travel alternatives (like high-speed rail and teleconference).
3. Installing residential solar and increasing home energy efficiency.
4. Eating more plant-rich meals.

Of the behaviors surveyed, three of the top six most impactful relate to alternatives to gas-powered car use: from going totally car-free, to shifting to hybrid or electric, to opting for public or active transit. The magnitude of the potential reductions is significant: car-free living is more impactful than adopting home solar and going vegan combined.

On the other hand, some common "green" behaviors like composting, while valuable, have a minimal effect on emissions. We refer to these remaining shifts as "Supplementary Shifts."

Prioritization is key: the difference in emissions impact between behaviors is massive, and shifts toward high-impact behaviors dwarf the adoption of lower-impact actions. For example, going car-free is 78 times more impactful than composting. Our findings underline the need to redirect individual, industry and policy attention toward the highest-impact shifts.

Crucially, our analysis finds a significant gap between theoretical potential and real-world achievement - highlighting that without systemic support, interventions aimed at changing individual behaviors cannot realize the emissions reductions that the climate crisis demands.

Our data shows that combining all key behavioral shifts could theoretically reduce emissions by 7.2 tons (6.53 tonnes) of carbon dioxide-equivalent per capita/year [tCO2e/cap/yr]. This would theoretically offset all the average global citizen's per capita emissions, which were 6.28 tonnes of carbon dioxide-equivalent per capita/year [tCO2e/cap/yr] in 2021 (Climate Watch 2022). However, the real-world impact is substantially lower, achieving only about 10% of this.

Finally, the paper provides recommendations to policymakers for supporting high-impact behavior shifts. For example, to support the shift to active and public transit, policymakers can implement targeted incentives such as e-bike subsidy programs, as well as invest in public and active transport.

To facilitate the transition to clean home energy, policymakers can support solar-ready building requirements, feed-in tariffs (where utilities are obligated to purchase electricity generated from renewable sources), and subsidies.

And to support the shift to more plant-rich meals, policymakers can leverage procurement standards and choice architecture strategies, such as ensuring plant-rich options are easily available and appealing.

Industry leaders should likewise align sustainability initiatives with these Priority Shifts, applying effective behavioral tools rather than passive approaches. Financial institutions can offer low-rate loans for energy-efficient home upgrades, automotive companies can provide incentives toward hybrid or EV purchases, and food service providers can reduce climate impacts by making plant-rich options the default or featured menu items.

Individuals, meanwhile, can maximize their climate impact by personally changing key behaviors in line with the priorities the research identifies, and collectively pushing for better policies and industry practices that make sustainable options more widely available and affordable.

Across behaviors, policies should aim to use the most effective behavioral tools. Our research shows choice architecture (such as making sustainable options more appealing and accessible) and commitment-based approaches (such as encouraging commitments or pledges to take public transport more often) emerge as particularly effective tools. Popular interventions like providing enhanced information (such as carbon calculators) show some of the lowest impact.

In conclusion, we recommend that researchers expand the scope of behavior change interventions, focusing on high-impact but understudied behaviors like adopting solar or swapping gas cars for hybrid or electric. Researchers should also aim to test broader systems-level strategies and report the impact of attempts to change behavior both in terms of behavior change and projected emissions reductions. Finally, new research is needed on understudied geographies, such as Asia, Africa and Latin America.