Measuring Climate Performance Against National Commitments: A Gap-to-Target Indicator for the Kyoto Protocol, First and Second NDCs

This paper introduces a new indicator to assess countries' climate performance by comparing their effective greenhouse gas (GHG) emissions with the levels implied by their commitments under the Kyoto Protocol and the first and second Nationally Determined Contributions (NDCs). Existing climate indices track emissions or policy ambition but do not provide a harmonised, cross-country measure of the distance to pledged mitigation targets. Building on the literature on distance-to-target metrics, we develop a simple Gap-to-Target indicator applicable across successive commitment cycles. Using data for 135 countries over 1990-2024, we compute annual measures of alignment with national pledges and document systematic patterns across income groups, regions, and commitment periods. Descriptive trends reveal a widening disconnect between rising ambition and realised emissions, especially under the second NDC cycle. Dynamic system-GMM estimations show that economic development, renewable energy deployment, environmental expenditure, fiscal capacity, and climate vulnerability are key determinants of countries' ability to meet their commitments. The Gap-to-Target indicator offers policymakers and international financial institutions a transparent tool to track performance, identify structural implementation gaps, and better target climate finance, and it can be extended to other environmental commitments such as biodiversity or land degradation neutrality. The indicator can also be extended to the upcoming 2025 NDCs and future commitment cycles, enhancing its relevance for long-term climate governance. With appropriate sub-national data, it could further be adapted to regional and local authorities, supporting the decentralisation of climate action monitoring.