Large Language Models Enable Personalized Nudges to Promote Carbon Offsetting Among Air Travellers

Nudge strategies are effective tools for promoting sustainable behaviour, but their impact depends on individual preferences. By emulating human decision-making, large language models (LLMs) offer a cost-effective route for tailoring nudges without extensive behavioural datasets, yet this potential remains unexplored. Focusing on aviation, we use LLMs to design personalized decoy-based nudge strategies that encourage air travellers to voluntarily offset CO$_2$ emissions from flights, and validate their efficacy through 3495 surveys from China, Germany, India, Singapore, and the United States. Results show that LLM-informed personalized nudges are more effective than uniform settings, raising offsetting rates by 3-7$\%$ and yielding an additional 2.3 million tonnes of CO$_2$ mitigated annually in aviation. This improvement is driven primarily by increased participation among sceptical travellers with low trust in offset programmes. Our study highlights the potential of LLM-driven personalized nudging strategies for boosting offsetting behaviours to accelerate aviation decarbonization.