The Copenhagen Accord's failure and the Paris Agreement's success show the importance of flexible commitments. Critically examine.

At COP15 (Copenhagen, 2009), talks to agree a binding successor to Kyoto collapsed. The COP only "took note" of the Copenhagen Accord and did not adopt it [1]. Six years later, COP21 adopted the Paris Agreement, a legally binding treaty built on pledges that each country sets for itself [2]. The contrast shows that flexibility won participation. It has not yet won enough ambition.

Why Copenhagen faltered

• Top-down legacy: Kyoto set binding targets only for developed countries and economies in transition [1]. Trying to extend fixed targets deepened the divide between developed and developing countries.
• Consensus trap: A small group of countries drafted the Accord. Under consensus rules, the countries that objected blocked its adoption. More than 140 countries backed it only later [1].
• Hidden legacy: Its voluntary pledge-and-review approach later became the base for Paris.

How flexibility delivered Paris

• Bottom-up NDCs: Each country sets its own target to suit its national circumstances. This respects CBDR-RC (common but differentiated responsibilities and respective capabilities).
• Universality: The same rules apply to all Parties, whatever their level of development [2]. This brought major emitters such as India and China into the system.
• Binding process, not binding outcomes: Countries must submit NDCs on a five-year cycle and report under the Enhanced Transparency Framework [2]. The Agreement entered into force in November 2016, within a year of adoption [2].

Limits of flexibility

• Ambition gap: Even if every NDC is fully met, warming reaches 2.3–2.5°C. Current policies point to up to 2.8°C [3].
• Delay: Only about a third of Parties had filed new 2035 NDCs by 30 September 2025 [3].
• No cost to leaving: The expected US withdrawal cancels out about 0.1°C of the improvement [3].
• Equity concern: Self-set pledges weaken the idea of differentiated responsibility. Developed countries' finance commitments also stay voluntary and disputed.

Overall, flexibility solved the question of who takes part, which sank Copenhagen, but not the question of how much each country does. The way forward is to:

• use the Global Stocktake to tighten successive NDCs;
• make climate finance predictable and consistent with CBDR-RC;
• have India submit a credible NDC on time to strengthen its bargaining position.

This would move flexible commitments towards the 1.5°C goal and SDG 13.