Introduction

This report analyses how the top 20 highest-emitting countries address pro-climate behaviour within their Nationally Determined Contributions (NDCs). NDCs are essential components of the Paris Agreement and outline how nations plan to reduce greenhouse gas (GHG) emissions. The report identifies a gap between current climate pledges and the necessary actions to limit global warming to 1.5°C. Emphasis is placed on the importance of integrating behaviour change into NDCs, which could reduce GHG emissions by 40–70% by 2050.

Approach and methodology

The research focuses on the top 20 emitters, representing 82% of global GHG emissions, using a systematic analysis of their NDCs. The analysis identifies nine key “priority practices” that have the greatest potential to reduce emissions across three sectors: food, mobility, and energy. The study uses a scoring system to evaluate whether countries have policies, actions, or targets addressing these practices. Behaviour change tools are categorised into three types: providing enhanced or personalised information, incentives, and improving the decision-making context.

Summary and recommendations

The report finds that while some of the top 20 emitters are making progress on certain behaviour changes, there are critical gaps. Only three priority practices are consistently addressed: promoting electric or hybrid vehicles, expanding public transport use, and improving household energy efficiency through insulation or energy-efficient appliances. These practices appear in at least half of the countries’ NDCs.

Two high-impact practices, reducing air travel and promoting sustainable diets, are significantly underrepresented. No country addresses reducing air travel, and only the UK mentions promoting sustainable dietary shifts. The report suggests that countries should prioritise these overlooked areas in future NDC updates.

In terms of tools, countries most frequently focus on improving the decision-making context. For example, many nations plan to build infrastructure for electric vehicles, but fewer use a combination of incentives, information, and infrastructure to support behaviour change comprehensively. The report recommends that countries should adopt a broader range of tools, including financial incentives and educational campaigns, to drive more significant changes.

Countries are also encouraged to develop policies that account for their unique socio-economic and regional characteristics. Monitoring and evaluating the effectiveness of behaviour change initiatives should become an integral part of the NDC process.

Key statistics

• The top 20 emitters account for 82% of global GHG emissions, with China, the US, and India contributing nearly 50%.
• Comprehensive behaviour changes could cut GHG emissions by 40–70% by 2050, according to the Intergovernmental Panel on Climate Change (IPCC).
• Only three of nine priority practices are consistently addressed by at least half of the top 20 emitters.
• Reducing air travel and promoting sustainable diets, two of the most impactful behaviour changes, are mentioned in one or none of the NDCs.

Recommendations

The report recommends that countries expand their NDCs to include behaviour changes in underrepresented areas such as sustainable diets and air travel. Additionally, nations should leverage a full range of behaviour change tools—beyond just infrastructure improvements—to include incentives and personalised information. Countries should monitor the effectiveness of these actions through continued assessment, potentially integrating this into the United Nations’ global stocktake process. Finally, addressing both upstream (systems) and downstream (individual behaviour) interventions will be essential for achieving the emissions reductions necessary to meet global climate goals.