Low-carbon lifestyles deliver broad climate benefits, strengthened by environmental self-identity

Demand-side changes are increasingly recognized as critical for meeting climate targets, yet their true mitigation potential depends on indirect effects such as economic rebound or behavioral spillover, which are difficult to quantify. Empirical evidence linking real-world lifestyles to net greenhouse gas (GHG) impacts in representative populations is scarce. Here we combine financial transaction data, registry records, and survey responses from a randomly selected sample of 847 Swedish single-adult households to quantify the direct and indirect GHG impacts of three high-impact lifestyle choices: living without a car, avoiding air travel, and adopting a vegetarian diet. These behaviours were associated with net reductions of 32%, 20%, and 12% of average annual emissions (1.9, 1.2, and 0.7 tCO ₂ e per person, respectively). In all cases, reductions exceeded the direct effects, indicating that—contrary to common assumptions of rebound—other domains of spending also shifted toward lower emissions. Individuals with stronger environmental self-identity achieved an additional 0.10--0.15~tCO ₂ e/year. Our findings suggest that estimates of demand-side mitigation potential may be systematically underestimated, and that identity could play a significant role in amplifying the climate benefits of lifestyle change.