How the Politics of National Determination Erode Trust in Climate Cooperation

[Wassim Dbouk is a Research Fellow at the Southampton Marine and Maritime Institute at the University of Southampton and serves as a climate negotiator for Lebanon, where he leads on the negotiations on the Just Transition Work Programme.]

At the June 2026 climate meetings in Bonn (SB64), I participated in negotiations under the Just Transition Work Programme (JTWP) that revealed competing invocations of national determination, raising the question of how their political legitimacy should be assessed. Many oil-producing developing-country Parties sought to rely on national determination to resist attempts by some developed-country Parties to prioritise a transition away from fossil fuels. Proponents of climate-related carbon border measures (CBMs) – notably the European Union (EU) and the United Kingdom (UK) – also sought to defend those measures as nationally-determined policies in response to broader developing-country groups’ concerns about their adoption outside a multilateral process and their potential to shift transition burdens onto developing-country Parties. 

These dynamics bring into focus related scholarship on ambition and differentiation under the Paris Agreement, the distributive effects of CBMs and their implications for common but differentiated responsibilities and respective capabilities (CBDR-RC), and on trust in climate negotiations. I contribute to this literature by examining how Parties may draw on the structure of the Paris Agreement and the International Court of Justice’s (ICJ) 23 July 2025 Advisory Opinion in Obligations of States in respect of Climate Change (ICJ AO) to legitimise some invocations of national determination while contesting others. I argue that selectively weighting the Agreement’s goals and principles in making those judgements departs from the constructive ambiguity underpinning the Paris compromise, weakens Parties’ credibility and erodes the trust on which climate cooperation depends. To address this problem, I propose an interpretative framework for evaluating competing claims about the political legitimacy of nationally-determined measures while preserving mitigation urgency and supporting constructive climate diplomacy.

National Determination is Not Unlimited 

The Paris Agreement’s framework for cooperative climate action relies on a pledge-and-review architecture to raise ambition while preserving national determination. This balance helped secure broad participation, but the Paris compromise depended heavily on constructive ambiguity around how equity and CBDR-RC should be operationalised across the Agreement’s goals. Article 2(1) situates its mitigation, adaptation and finance goals in the context of sustainable development and poverty eradication, while Article 2(2) requires its implementation to reflect equity and CBDR-RC. Yet neither provision supplies a clear framework for determining how the Agreement’s goals and principles should be weighed as national claims to equitable climate action are subjected to international scrutiny and contestation. This creates scope for Parties to mobilise those goals and principles selectively when defending some invocations of national determination and challenging others.

The ICJ AO clarifies the legal limits of national determination. It confirms that States’ customary obligation to prevent significant harm to the climate system entails a stringent standard of due diligence (paras. 135 and 138). In interpreting the Paris Agreement, the Court made the 1.5°C temperature goal a central interpretive anchor for its analysis of mitigation and nationally-determined contribution (NDC) obligations (paras. 223-225 and 231). It treated progression and highest possible ambition as prescriptive standards and required NDCs to be informed by the global stocktake (paras. 240-243). It then held that Parties’ discretion in preparing NDCs is limited and subject to stringent due diligence, and that their NDCs, taken together, must be capable of achieving that goal (paras. 245-246). Although the Court identified historical contributions as relevant to the differentiated assessment of Parties’ NDCs, its reasoning gave greater practical weight to present capabilities and available resources in applying CBDR-RC (paras. 247-248 and 290-292).

The Court addressed mitigation and NDC obligations in greater detail (paras. 230-254) than adaptation (paras. 255-259) or cooperation and means of implementation (paras. 260-267). It assessed adaptation duties through due diligence but noted that Article 7(9) does not prescribe particular actions (paras. 255-258); recognised States’ freedom to choose the means of cooperation, subject to good faith and due diligence (para. 262); and did not determine the amount or level of Article 9 support (para. 265). The AO request’s negotiated framing and the Court’s decision to centre its analysis on the duty to protect the climate system from anthropogenic greenhouse gas (GHG) emissions may partly explain this imbalance (para. 100). Yet having recognised that mitigation, adaptation and support obligations are mutually supportive and interdependent, the Court did not develop the practical legal consequences of that relationship (paras. 185, 227-228, 259 and 264-265).

Despite this limitation, the Court’s clarification of mitigation and NDC obligations remains valuable because it limits political claims that national determination alone can legitimise mitigation pathways difficult to reconcile with deep, rapid and sustained emissions reductions. It supports scrutiny of attempts to treat national circumstances or alternative mitigation options as sufficient to defend continued fossil fuel extraction and production. However, the same emphasis that strengthens this scrutiny can create diplomatic risks in a multilateral regime where progress depends on consensus sustained by a delicate balance amongst the Agreement’s obligations and principles.

The Selectivity Problem

In the JTWP, some developed-country Parties have sought to foreground the first global stocktake’s reference to transitioning away from fossil fuels in energy systems as consistent with the 1.5 °C temperature goal (GST, para. 28(d)). Many oil-producing developing countries have invoked national determination as a defence against this move. They see it as a top-down effort to prioritise one mitigation pathway over their sovereign choice of just transition pathways that respond to their national circumstances, including those that rely on carbon capture technologies and economic diversification. That invocation should not, however, act as a shield for continued reliance on fossil fuels, which account for the largest share of GHG emissions. Still, if the climate regime is to sustain trust and effective diplomacy, this defensive claim warrants comparative examination, set against the way national determination is invoked to justify CBMs.

CBMs are defended as nationally-determined mitigation policies designed to prevent carbon leakage and protect the integrity of domestic climate regulation (European Commission; HMRC, 2026). These legitimate regulatory objectives underpin CBM proponents’ claim that the measures align with the 1.5°C temperature goal. Yet CBMs can also affect exporters, producers, and workers in countries that did not design them. They may entrench structural dependency by imposing administrative and financial burdens, narrowing policy space, and shifting transition costs onto economies with lower historical responsibility and fewer resources to respond. Although their legality and distributive effects engage international trade law, particularly World Trade Organization rules, the Paris Agreement’s aims and principles inform assessments of their political legitimacy when they are defended and contested in international climate negotiations.

Selectivity arises when CBM proponents treat alignment with 1.5°C as sufficient to legitimise CBMs as nationally-determined measures while giving insufficient weight to the Paris Agreement’s other goals and principles implicated by their effects. This approach makes an interpretation of equity and CBDR-RC centred on mitigation and present capabilities the benchmark for judging the political legitimacy of competing invocations of national determination. In doing so, CBM proponents narrow the interpretive space preserved by the Paris compromise and weaken their credibility as negotiating partners committed to the coherent implementation of the Agreement’s interdependent obligations. This can embolden oil-producing States to defend nationally-determined pathways that maintain fossil fuel extraction and production by drawing on an alternative reading of the Agreement that reflects their understanding of equity and CBDR-RC and gives greater weight to historical responsibility when differentiating mitigation obligations across States. Together, these claims create a cycle of selective legitimation that can harden negotiating positions, erode trust and fuel obstruction in climate negotiations.

A Broader Credibility Test

CBM proponents’ reliance on the temperature goal also exposes their position to a further credibility test. If alignment with 1.5°C supports the political legitimacy of CBMs, their credibility depends on applying the same standard to financial regulation and policies addressing consumption within their jurisdictions.

The  documents the role of EU- and UK-based banks in fossil fuel financing. It found that, across a dataset of roughly 2,000 banks, EU- and UK-based institutions accounted for 11.1% and 5.8% of global fossil fuel financing respectively in 2025 (pp. 24-25). The report shows that EU- and UK-based banks continued to finance companies pursuing fossil fuel expansion in 2025, in several cases at higher levels than in 2024 (pp. 31-35).

The regulatory response to these financing patterns should be assessed in light of Article 2(1)(c)’s aim to make finance flows consistent with low-emission and climate-resilient development. Yet the Paris Agreement does not specify how this aim bears on cross-border fossil fuel finance. The Court’s analysis in the AO does not close this gap. Although it confirms that due diligence extends to private activities under a State’s jurisdiction and that State responsibility may arise from regulatory failure rather than attribution of private conduct itself, it does not develop the implications for banks financing emissions-intensive activities abroad (paras. 252, 282 and 428). This leaves scope for CBM proponents to demand closer alignment with the temperature goal from foreign producers than from the financial institutions they regulate, allowing financial benefits to remain concentrated within their jurisdictions while the mitigation burdens fall on countries where the associated emissions occur.

The credibility test extends beyond financial regulation to energy consumption. The Unjust Transition report documents stark inequalities in global energy use. An average person in the Global North uses enough energy each year to meet the modern energy needs of more than 45 people in the Global South. The richest 10% globally also consumed half of all energy over the past decade, compared with 8% for the poorest half (p. 14). The World Inequality Report 2026 identifies a related imbalance in carbon-intensive ownership. The UK and several EU Member States, including France, Italy and Germany, have positive net foreign-ownership emissions, with their residents’ foreign assets generating more emissions than domestic assets owned by foreign investors (p. 119; Figure 6.4, p. 121). These patterns pose a serious credibility problem for the EU and UK when invoking 1.5°C to legitimise CBMs, particularly in light of the ICJ’s finding that a State’s failure to take appropriate action on emissions from fossil fuel consumption may constitute an internationally wrongful act (para. 427).

Against this background, repeated statements by CBM-supporting delegates in the JTWP that “the science is not negotiable” risked compounding the selectivity problem. Scientific findings remain indispensable, but invoking them to defend CBMs more readily than to guide financial regulation and consumption policy can weaken both proponents’ credibility and science’s role as a shared basis for cooperation. A more constructive approach would align trade, finance and mitigation policies with the temperature goal, address carbon-intensive consumption, and redirect finance towards renewable energy, energy efficiency and support for less-resourced States pursuing low-emission pathways suited to their national circumstances.

A Trust-Preserving Framework for Assessing Political Legitimacy

The ICJ’s AO strengthens the legal basis for demanding greater collective mitigation ambition by subjecting Parties’ discretion over NDCs to stringent due diligence and requiring those contributions, when taken together, to be capable of achieving 1.5°C (paras. 245-246). Yet I conclude that the Paris Agreement’s constructive ambiguity around equity and CBDR-RC allows Parties to use the AO’s mitigation-centred framing to present some invocations of national determination as politically legitimate while contesting others. In disputes over fossil fuel pathways and CBMs, this selective legitimation weakens Parties’ credibility, erodes trust and obstructs the cooperation needed for effective mitigation.

I therefore propose an interpretative framework for evaluating claims about the political legitimacy of nationally-determined measures in climate negotiations based on three criteria: (1) a credible contribution to 1.5°C; (2) consistency with the interdependence of mitigation, adaptation and support, including finance, read in light of equity, CBDR-RC, sustainable development and poverty eradication; and (3) consistency between the standard used to legitimise the measure and the State’s wider policies and exercise of regulatory authority. Applied consistently, the framework would clarify disagreements, discourage reciprocal selectivity and preserve mitigation urgency while guiding negotiations towards constructive cooperation.

Photo attribution: Author’s own photo during the Subsidiary Body meetings in Bonn in 2025.