How do climate summits take shape?

Once a year, the countries that have ratified the United Nations Framework Convention on Climate Change (UNFCCC)—the international treaty laying the foundations for agreements such as the Kyoto Protocol and the Paris Agreement—come together at the Conferences of the Parties, better known as COPs. These annual summits are the flagship events when it comes to international climate negotiations and are intended to drive progress toward global climate goals.

What is a COP and how do climate negotiations begin?

A COP is the annual climate summit that brings together the countries that have signed the UNFCCC. The treaty, which entered into force in 1994, has “near-universal membership,” having been ratified by 197 countries, known as the Parties to the Convention.

Although, from a logistical perspective, the summit itself lasts only two weeks, in actual fact its work extends far beyond that period. What happens between COPs is crucial to maintaining forward momentum, ensuring continuity in the discussions and delivering on agreed outcomes. Collaboration between the UNFCCC, the outgoing COP Presidency, and the host country of the next summit helps ensure that commitments are carried forward and that negotiations continue to advance.

Negotiations begin months before the summit itself, making each COP part of an ongoing process rather than a standalone event. According to Olga Alcaraz, academic at the Polytechnic University of Catalonia (UPC) and coordinator of the Group on Governance of Climate Change (GGCC), “between each summit there is an entire process of meetings held in different parts of the world,” including the mid-year technical meetings and the June sessions recently held in Bonn, Germany.

To address unresolved issues, informal consultations are convened with Heads of Delegation and negotiating groups. These include a series of high-level retreats, such as the one held in Shamakhi, Azerbaijan, as well as other preparatory meetings that help define negotiating positions. Every stage helps to “move the work forward and smooth the path toward the COP,” says Alcaraz.

The host country’s role in climate diplomacy

The choice of host country is a hugely important one. The host plays a central role in sustainability and climate diplomacy, acting as a key mediator and facilitator in negotiations between states. As COP President, its responsibilities extend throughout the year until the following summit. For example, Brazil held the Presidency of COP30 in 2025, but its role did not end when the summit concluded. It continued to participate in institutional initiatives until COP31 in 2026, when Türkiye took over the Presidency.

Throughout the cycle of meetings, negotiations and consultations, the host country is expected to distance itself from its own national interests and perform a diplomatic and neutral role, helping to “build consensus beyond its own climate agenda”, according to Alcaraz. This approach prioritizes global interests over regional ones. The host therefore acts as the logistical and political engine that helps transform international negotiations into tangible outcomes by identifying common ground, defining red lines, and facilitating agreement. Given that decisions are reached by consensus, the host country is expected to safeguard the collective interest.

What exactly is negotiated ahead of a COP?

Preparatory meetings lay the foundations and frameworks for discussion, but real and concrete agreements must be reached during the summit itself. Key issues for the upcoming COP are identified in advance, although some ambitious objectives may ultimately not be addressed during the summit and may instead be deferred to the following year. As Alcaraz notes, “what should be mandatory as a result of the preparatory negotiations may end up becoming a recommendation” by the close of the summit, with responsibility therefore passing to the next COP.

In the lead-up to a COP, a series of meetings takes place to move forward negotiations as far as possible. These include regular sessions and institutional forums that are critical for a number of strategic priorities:

• The Bonn sessions
• The G20 summits
• Climate Week NYC
• The Copenhagen Climate Ministerial

The Bonn sessions: These meetings (for COP31, the Bonn SB64 session) are essential for shaping the thematic agenda, setting concrete objectives, and building alliances that will form the structure of the summit. They are held in Bonn because it is home to the UN Climate Change Secretariat. “In Bonn, the specific workstreams that negotiators will seek to advance at the COP are defined, and some of the key issues that will later be put forward for consensus at the Summit are identified,” explains Alcaraz. Discussions take place primarily within negotiating blocs rather than between individual countries, helping to ensure broader representation of key concerns and streamlining the process. Beyond negotiations, the sessions also serve as important technical meetings, including reviews of countries’ progress. For example, the Just Transition mechanism advanced at COP30 has just been during Bonn SB64.

The G20 (Group of 20): The G20 summits help shape the specific climate themes that will feature prominently at the next COP. “From the conclusions reached at the G20, we can usually already see the issues the group is pushing and that will make their way onto the COP agenda,” explains Alcaraz.

Climate Week NYC: This event brings together the United Nations and government representatives with the aim of accelerating delivery on global commitments.

The Copenhagen Climate Ministerial: At this meeting, ministers from participating countries define their political positions and set their sights on specific priorities, such as global electrification or fulfilment of climate finance commitments.

How are alliances built ahead of a COP?

Building alliances ahead of a climate summit is a strategic process that extends beyond geopolitics and involves far more than governments alone. For COP31, one of the most significant partnerships is with the International Energy Agency (IEA).

“The IEA has always played a very active role,” says Alcaraz, noting that it has spent many years “developing scenarios for developing countries, major emerging economies and advanced economies”. She adds that “the current backdrop of heavy geopolitical tension makes the agency’s role even more important in establishing roadmaps and providing advice on specific issues”.

In preparation for COP31, cooperation with the IEA has also involved meetings at the agency’s headquarters in Paris, according to COP sources. However, Alcaraz stresses that this partnership is primarily knowledge-based, as the agency’s data are regarded as a benchmark by many climate research teams. The IEA is therefore not involved in negotiations themselves; rather, it provides advice based on “reliable, high-quality data”.

Frequently asked questions about climate summits and COPs

What is a COP?

A COP (Conference of the Parties) is the annual meeting of the countries that have ratified the United Nations Framework Convention on Climate Change (UNFCCC). Its purpose is to negotiate agreements and review progress on international climate action.

How long does it take to prepare a COP?

Although the summit itself lasts around two weeks, preparations take place throughout the year in the form of technical meetings, diplomatic consultations, and international gatherings that help move forward negotiations.

What role does the host country play?

The host country holds the COP Presidency and acts as a facilitator of negotiations. Its role is to promote consensus among the Parties and help move discussions toward common agreements.

What are the Bonn sessions and why are they important?

The Bonn sessions are annual technical meetings organized under the UNFCCC. They help define many of the issues, workstreams, and proposals that are later negotiated during the COP itself.

Which meetings help prepare for a climate summit?

Aside from the Bonn sessions, important preparatory forums include the G20 summits, Climate Week NYC, and the Copenhagen Climate Ministerial. These events help establish political priorities and build international alliances ahead of the event.

Why are pre-COP negotiations necessary?

Preparatory negotiations help countries iron out differences, identify areas of agreement, and reduce friction points before the summit. This groundwork makes it easier to reach decisions in a process where agreements are generally adopted by consensus.

Who participates in international climate negotiations?

In addition to governments, participants include international organizations, specialized agencies, scientific representatives, civil society organisations, and observer entities that lend support and technical expertise to the negotiating process.