Because the Paris Agreement is a universal, legally binding agreement to tackle climate change under international law, it joins other such agreements as the highest expression of political intent and will. Yes, it has binding and non-binding components, but overall it is durable and underpins decisive real-economy change and drives corresponding national legislation and policy. Entering into legally binding agreements sends a strong signal to corporations, planners, investors and other implementers that governments will enforce climate policies. This is an agreement between countries in which each country indicates its intent to be bound at the international level. Each country follows its own domestic authorization process based on its own unique legal system, before joining this international agreement.

This legal form makes the Paris Agreement, adopted December 12, 2015 at COP21, fundamentally different from the Kyoto Protocol. The Kyoto Protocol was a product of its time, with only a small number of countries taking on binding emission reduction targets. The Paris Agreement moves beyond that, achieving legal rigor while ensuring universal participation. While Kyoto succeeded in reducing emissions in some developed countries, it only had binding targets for a few countries.

By contrast, the Paris Agreement includes every country and thus has to accommodate the different development stages of those countries. The targets themselves are not binding, but all countries are obliged to prepare, communicate and maintain their targets and pursue domestic measures to achieve them. Framing the obligation in this way is likely to increase the likelihood of implementation, since the targets are nationally-determined and in many countries, already anchored in nationally binding laws and regulations. It’s a more accommodating way to bind countries to deliver their national plans, while recognizing that some countries are not in a position to have their targets stated directly into a treaty.

The Agreement has strong legally binding provisions on how to measure, report and verify emissions reduction commitments. Countries will be required to measure their emissions in the same way, report on them in the same frequency and format and have them verified through an independent technical process. The Agreement also ensures that countries must come to a multilateral setting to discuss progress on implementation of their emissions reduction targets. This commitment from all countries provides the means to track progress on how countries implement their commitments. This means there are opportunities to “name and shame” countries for not meeting their commitments. It is here that the court of international public opinion acts to judge and pressure countries.

More specifically, the Paris Agreement includes a set of legally binding obligations on a range of issues, including:


  • Each Party “shall prepare, communicate and maintain successive nationally determined contributions that it intends to achieve. Parties shall pursue domestic mitigation measures with the aim of achieving the objectives of such contributions.”
  • Each Party “shall communicate a nationally determined contribution every five years…”
  • “Each Party shall account for their nationally determined contributions.”


  • Each Party shall engage in adaptation planning processes

Transparency and Accountability

  • “Each Party shall regularly provide”… “a national inventory” and “information necessary to track progress made in implementing and achieving its nationally determined contribution”
  • “Information by each Party shall undergo a technical expert review.”
  • “Each Party shall participate in a facilitative, multilateral consideration of progress…The review shall also identify areas of improvement for the Party.”
  • “Support shall be provided for the building of transparency-related capacity of developing country Parties on a continuous basis.”


  • “Developed countries shall provide financial resources to assist developing country Parties with respect to both mitigation and adaptation in continuation of their existing obligations under the Convention.”

Finally, the Paris Agreement provides for the establishment of a compliance mechanism in the form of an expert committee “to facilitate implementation and promote compliance with the provisions of this Agreement,” underscoring the seriousness in which all countries have entered into the Paris Agreement.

Legally binding agreements under international law act a bit like credit rating agencies. While there may be no obvious penalty, those that default or break their promises lose credibility, diplomatic standing and trust among their peers, which can have effects in other venues, on other issues and with investors and corporations.