Nationally Determined Contributions (NDCs) are a core concept and a set of national action plans under the Paris Agreement, a legally binding international treaty adopted in 2015. The NDCs were created to solve the problem of achieving the Paris Agreement's long-term goal: limiting the rise in global average temperature to well below 2°C above pre-industrial levels, and pursuing efforts to limit it to 1.5°C. They replaced the previous system of Intended Nationally Determined Contributions (INDCs), which were non-binding initial pledges made before the Paris Agreement.
The mechanism works by requiring each of the 195 Parties to the Paris Agreement to prepare, communicate, and maintain successive NDCs, as stipulated in Article 4, paragraph 2. These are self-defined national climate pledges that detail how a country will contribute to reducing greenhouse gas (GHG) emissions (mitigation) and adapting to climate change impacts. Key provisions include the ratchet mechanism, which mandates that NDCs must be updated every five years and represent a progression over the previous one, reflecting the country's "highest possible ambition". The NDCs are not legally binding in terms of achieving the specific targets, but the Paris Agreement creates an obligation of conduct to pursue domestic mitigation measures with the aim of achieving the objectives.
NDCs connect directly to the Paris Agreement and the United Nations Framework Convention on Climate Change (UNFCCC). They are also informed by the Global Stocktake (GST), a process that assesses the world's collective progress every five years, with the first GST in 2023 informing the preparation of subsequent NDCs. The third round of NDCs, known as NDC 3.0, is due by early 2025 and will detail intended climate actions through 2035. While the core structure of the five-year cycle and the principle of progression have stayed the same, the focus has recently shifted to enhancing ambition, transparency, and implementation strategies in the new round of NDCs.