How countries define climate action in Paris Agreement pledges – and why a standard format could help assess outcomes

As the world grapples with how to tackle climate change, countries that signed the Paris Agreement outline their commitments to reduce emissions in documents called Nationally Determined Contributions (NDCs). These are official climate action plans that each country submits to the United Nations Framework Convention on Climate Change (UNFCCC) every five years, detailing their reduction targets and strategies for achieving them. A cornerstone of the Paris Agreement, NDCs are designed to track global progress and encourage increasingly ambitious climate action over time. While they are often scrutinized for their emissions targets, new research suggests they contain much more – revealing countries’ broader priorities, challenges and approaches to sustainability.

Our team, which included researchers from ESCP Business School and Universitat Autònoma de Barcelona, applied methods from computational linguistics – which uses machine learning to analyze text – to over 300 NDCs submitted by nations worldwide. Our study identified 21 key topics within the documents, which we grouped into seven broader themes including development, mitigation targets, and impacts of climate change.

A tale of two worlds: how climate priorities differ across countries

One of the study’s most striking findings is the contrast in how higher-income and lower-income countries frame their climate pledges.

Wealthier nations such as the US, Japan and the EU (which speaks for its 27 member states) tend to focus on emissions reduction targets but often lack detailed roadmaps of policies or regulatory measures to achieve them. For instance, the EU’s first NDC consists of a concise statement of its emissions target accompanied by a table of technical information and a brief “follow-up” section. At around 1,000 words, the document is one of the shortest pledges. While the bloc’s updated NDCs do provide some summaries of policies and legislation, details are lacking on how these contribute to hitting targets. The texts include general statements such as: “sustainable transport fuels can play a key role in reducing greenhouse gas emissions”. Similarly, the United States’ updated 2021 NDC sets a target of reducing net greenhouse gas emissions by 50-52% below 2005 levels by 2030, but lacks details on concrete policies in the two-page section outlining the plan for achieving this goal.

In contrast, developing nations often take a broader approach, embedding climate policy within sustainable development goals. Their NDCs highlight economic growth, social justice and adaptation to climate impacts alongside mitigation. Many emphasize that they need financial and technological support from wealthier nations to meet their commitments. Venezuela’s updated 2021 NDC is perhaps the most extreme example of this. Exceeding 76,000 words, the document is the longest of all submissions and incorporates climate action into a wider eco-socialist “political vision of sustainable development of the country”.

Some developing countries have produced transparent, clear and detailed NDCs despite their limited resources. Ethiopia’s updated 2021 NDC provides sector-specific projections for emissions under different scenarios along with clear policy interventions to achieve its targets. Vanuatu’s updated 2022 submission systematically links policy actions to relevant sustainable development goals and specifies the level of international financial support required for implementation. These examples illustrate how some lower-income nations are not only integrating climate action into broader development plans but also outlining concrete pathways for carrying them out.

The contrast between these NDCs and those submitted by high-income countries raises fundamental questions about climate justice. For example, who should bear the economic burden of climate policies – developed nations with historically high emissions or developing countries striving for economic growth? This question challenges the fairness of imposing uniform climate policies on countries with vastly different economic capacities and historical contributions to global emissions. More questions include the following: how can climate policies ensure a just transition for industries and regions disproportionately affected by emissions reductions? How can policies be designed to minimize social costs while achieving environmental goals? The NDCs of developing nations reflect these issues, balancing climate action with pressing economic and social challenges.

Read more:
The ‘degrowth’ movement envisions global climate justice, but must adapt to global south realities

How have climate pledges changed over time?

Our study also tracked how countries’ NDCs have evolved. Early NDCs were often broad statements of intent, focusing on general commitments rather than concrete actions. More recent updates tend to be more detailed, with some countries breaking down mitigation strategies by sectors such as energy, agriculture and transportation. However, transparency remains an issue – many pledges still lack specifics and details on how governments plan to finance or implement their climate goals, leaving uncertainty about whether pledges will translate into action.

Which countries share similar priorities?

By using topic modelling, we identified nine country groups with similar approaches to their climate pledges, which are identified in the map below.

One cluster, which includes Brazil, Russia and other former Soviet states, emphasizes the implications of climate action on economic development. Meanwhile, Small Island Developing States (SIDS), which are highly vulnerable to the impacts of climate change, highlight adaptation and the need for international support.

These clusters highlight the complex trade-offs that countries face in balancing emissions reduction with economic and social priorities. But we think they also highlight the deeper ideological and political divides that shape climate commitments. For wealthier, market-driven economies, the challenge often lies in reconciling emissions reduction with growth-dependent models, competitive industrial policies and the influence of powerful fossil fuel interests. Meanwhile, in less capitalistic and state-controlled economies, social priorities – such as employment guarantees, energy affordability and political stability – may create resistance to aggressive decarbonization. In this sense, NDCs do not just reflect pragmatic trade-offs: the divergence in climate commitments also reflects how different governments define responsibility, fairness and the role of the state in shaping economic transformation.

Why standardizing NDCs matters

The lack of a standardized format for NDCs is a major challenge. Each country submits its document in its own format, making it difficult for researchers to assess which policies are effective and how much progress is actually being made. Some countries provide highly structured and detailed reports, while others submit only brief summaries. Many pledges still lack transparency, particularly on funding and implementation.

A common reporting format, developed by UNFCCC and based on lessons from the best examples of NDCs, could allow for better comparison of climate commitments and increase their transparency. Such a format could include standardized emissions baselines, sector-specific reduction targets, timelines for policy implementation and clear methodologies for measuring progress. It could also require countries to report on the financial and technological support they need – or provide – to ensure a just transition. These elements would not only make NDCs more comparable but also help identify gaps, best practices and potential areas for international cooperation.

As the next round of global climate negotiations approaches, there is a need for clearer commitments and greater accountability. Without them, the goals of the Paris Agreement may remain only on paper.