UN Climate Change Conference Belém

In his speech to the UN General Assembly Special Session on Climate Action in September 2025, UN Secretary-General António Guterres said “The Paris Agreement has made a difference. In the last ten years, projected global temperature rise has dropped from four degrees Celsius to less than three - if current NDCs [nationally determined contributions] are fully implemented. Now, we need new plans for 2035 that go much further, and much faster….We know it can be done.”

As governments and other stakeholders convene in Belém, Brazil, for the annual UN Climate Change Conference, the question on many minds, once again, is if this year will feature the necessary increase of ambitious action to reduce emissions and limit long-term global warming … or not.

What is Climate Change?

Climate change refers to long-term shifts in temperatures and weather patterns. Such shifts can be natural, due to changes in the sun’s activity or volcanic eruptions. However, human activities have been the main driver of climate change since the 1800s, primarily due to the burning of fossil fuels like coal, oil, and natural gas that release carbon dioxide (CO2).

Scientists have long known that the build-up of CO2 in the atmosphere can cause climate change. The first scientific article suggesting that atmospheric temperatures will rise as atmospheric CO2 concentrations increase was published over a hundred years ago in 1896. CO2 and several other gases collect in the atmosphere and act like a blanket—or a greenhouse—wrapped around the Earth. These “greenhouse gas” (GHG) emissions trap the sun’s heat and cause the planet to warm. CO2 is naturally present in the atmosphere as part of the Earth’s carbon cycle. But human activities, including burning fossil fuels, solid waste, trees and other biological materials, as well as certain chemical reactions, like cement production, are altering the carbon cycle by adding more CO2 to the atmosphere. At the same time, the expansion of industrial agriculture and increased urbanization are limiting the extent to which natural sinks, like forests and soils, remove and store atmospheric CO2. 

Other GHGs include methane (CH4), which is released through land-use changes, by livestock, from the production of coal, natural gas, and oil, as well as by the decay of organic waste in landfills. Nitrous oxide and fluorinated gases (especially hydrofluorocarbons (HFCs)) also contribute to climate change. Energy, industry, transport, buildings, agriculture and land use are among the main sectors emitting GHGs.

What is the United Nations Framework Convention on Climate Change?

Climate change is the classic global commons issue. The Earth’s climate system affects everyone, and broad international cooperation is required to mitigate global warming. The first step towards this cooperation was the establishment of the Intergovernmental Panel on Climate Change (IPCC) by the WMO and the UN Environment Programme, and endorsed by the UN General Assembly, in 1988. Its initial task was to prepare a comprehensive review with respect to the state of knowledge of climate change science and the social and economic impact of climate change and recommend potential response strategies and elements for inclusion in a possible future international convention on climate. 

The IPCC’s First Assessment Report in 1990 affirmed global warming as a serious threat. The report predicted that if states continue to pursue business as usual, the global average surface temperature would rise at a rate unprecedented in human history. This led the UN General Assembly to establish an intergovernmental negotiating committee to lay the groundwork for a framework convention on climate change, which began its work in February 1991. 

In June 1992, 154 countries signed the United Nations Framework Convention on Climate Change (UNFCCC) at the Earth Summit (United Nations Conference on Environment and Development) in Rio de Janeiro, Brazil. The Convention requires those Parties listed in its Annex I (industrialized countries and countries with economies in transition) to take steps aimed at returning individually or jointly to their 1990 GHG emission levels by 2000. It did not address emissions-reduction targets after 2000, but the text did provide for regular review of the adequacy of the commitments. 

The UNFCCC entered into force in March 1994. But immediately, a number of countries, led by the Alliance of Small Island States (AOSIS), and an international network of non-governmental organizations (NGOs) pressed for a significant strengthening of the treaty.

Kyoto Protocol: The first Conference of the Parties (COP) to the UNFCCC convened in Berlin in March 1995 and addressed the issue of regime strengthening. The COP agreed to define, by the end of 1997, quantitative limits on GHG emissions beyond 2000. After two years of difficult negotiations, the Kyoto Protocol was adopted at COP 3 in Japan at the end of 1997. 

The protocol required Annex I Parties to reduce their collective emissions of six GHGs (CO2, methane, nitrous oxide, HFCs, perfluorocarbons, and sulphur hexafluoride) by at least 5% below their 1990 levels between 2008 and 2012. Countries had different requirements within this collective mandate, ranging from limiting an increase to 10% for Iceland (which had already reduced its emissions by increasing reliance on geothermal and hydroelectric power) to 8% reductions for the European Union (EU) and most of the countries in Eastern Europe. The overall reduction target was not very ambitious and that limited the protocol’s impact from the start.

Paris Agreement: With increasing knowledge of the rapidly materializing climate impacts and with a view to global development patterns, efforts were launched to strengthen the global response to climate change and foster enhanced action by all countries—both developed and developing.  After four years of negotiations (2005-2009), a new agreement was supposed to be adopted at COP 15 in Copenhagen in 2009. When it was presented to the plenary for adoption, a long and acrimonious debate ensued. A group of countries blocked formal adoption of the agreement, calling the process that produced it “untransparent and undemocratic” because many delegates were not involved in the 11th hour negotiations that resulted in the final text of the “Copenhagen Accord.” In the end, rather than formally adopt it, the COP agreed to merely “take note” of the Copenhagen Accord. 

The Accord set forth a long-term, aspirational global goal of limiting temperature rise to no more than 2°C, established a process for recording voluntary mitigation targets and actions of both developed and developing countries, and agreed to increase funding for mitigation and adaptation by developing countries, including the goal for developed countries to jointly mobilize USD 100 billion per year by 2020. By 2010, more than 140 countries had endorsed the Accord, and more than 80 countries had submitted emissions targets and mitigation actions. This set the stage for another series of negotiations, beginning in 2011 that resulted in the Paris Agreement, which was adopted on 12 December 2015. 

The Paris Agreement builds on a bottom-up approach where countries periodically submit “nationally determined contributions” (NDCs). In five-year cycles, Parties are expected to “ratchet up” efforts to limit the increase in global temperature to “well below 2°C above preindustrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels.” To track progress, Parties submit detailed reports every two years, starting in 2024, and a Global Stocktake takes place every five years to assess collective progress in the implementation of the Paris Agreement and inform the preparation of the next round of NDCs.

What happened at COP 28 and 29?

Global Stocktake: The first Global Stocktake under the Paris Agreement concluded at COP 28 in Dubai in 2023. A synthesis report released prior to the conference noted that national mitigation commitments fell short by 20.3 to 23.9 gigatonnes of CO2 equivalent compared to the levels required to limit warming to 1.5°C by 2030. Thus, to achieve the Paris Agreement’s targets, global GHG emissions need to be cut by around 43% by 2030 and 60% by 2035 from 2019 levels, aiming for net-zero CO2 emissions by 2050.

Recognizing progress was too slow across all areas of climate action—from reducing GHG emissions, to strengthening resilience to a changing climate, to getting the financial and technological support to vulnerable nations—Parties responded with a decision on how to accelerate action across all areas by 2030. The decision concluding the first Global Stocktake calls upon Parties to contribute to global efforts to, among others:

• triple renewable energy capacity globally and double the global average annual rate of energy efficiency improvements by 2030;
• accelerate efforts towards the phase down of unabated coal power;
• accelerate efforts towards net zero emission energy systems, utilizing zero- and low-carbon fuels well before or by around mid-century;
• transition away from fossil fuels in energy systems so as to achieve net zero by 2050; 
• accelerate zero- and low-emission technologies, including renewables, nuclear, abatement and removal technologies such as carbon capture and utilization and storage, particularly in hard-to-abate sectors, and low-carbon hydrogen production;
• accelerate and substantially reduce non-CO2 emissions globally including, in particular, methane emissions by 2030;
• accelerate the reduction of emissions from road transport; and
• phase out inefficient fossil fuel subsidies. 

Loss and Damage: After years of discussion, COP 28 and the Conference of the Parties serving as the Meeting of the Parties to the Paris Agreement (CMA 5) operationalized a fund for responding to loss and damage in developing countries that are particularly vulnerable to the adverse effects of climate change. Subsequently, the newly established Board of the Fund selected the Philippines as its host country and selected Ibrahima Cheikh Diong as the inaugural Executive Director of the Fund for a four-year-term beginning 1 November 2024. Also, the consortium of the UN Office for Disaster Risk Reduction and the UN Office for Project Services was designated as the host of the Santiago Network on loss and damage, which aims to catalyze technical assistance.

Global Goal on Adaptation: In Dubai, Parties also adopted a framework for the Global Goal on Adaptation (GGA), which was defined in the Paris Agreement. The GGA Framework includes a range of thematic and dimensional targets and covers the themes of water, food, health, ecosystems, infrastructure, poverty eradication, and cultural heritage. The GGA aims to guide adaptation planning and strategies at all levels, and to align the necessary finance, technology, and capacity-building support.

Climate Finance: In 2024, Parties to the Paris Agreement set a new collective quantified goal (NCQG) on climate finance. They set a goal of: at least USD 300 billion per year by 2035 for developing countries’ climate action from a wide range of sources—public and private, bilateral and multilateral, including alternative sources—and with developed countries taking the lead. Developing countries are encouraged to make contributions on a voluntary basis. The relevant decision also calls on all actors to work together to scale up financing to developing countries for climate action from all public and private sources to at least USD 1.3 trillion per year by 2035.

The decision acknowledges the need for public and grant-based resources and highly concessional finance, particularly for adaptation and responding to loss and damage, especially for those most vulnerable to the adverse effects of climate change and with significant capacity constraints, such as the least developed countries (LDCs) and small island developing states (SIDS).

Market-based Cooperative Implementation: Another major outcome in Baku was the operationalization of the market-based cooperative implementation of the Paris Agreement (Articles 6.2 and 6.4). Parties had been negotiating the modalities for setting up the Agreement’s carbon markets for many years, with the aim to ensure that activities thereunder effectively deliver an overall mitigation in global emissions and comply with agreed-upon environmental safeguards, and monitoring and reporting provisions. The expectation is that this will support progress toward the goals of the Paris Agreement in a cost-efficient manner.

What to look for at COP 30?

Countries have made meaningful strides on climate action since 2015, but their commitments are not ambitious enough to limit warming to under 1.5°C by 2030. In fact, according to the UN Environment Programme’s 2024 Emissions Gap Report, governments must collectively commit to cutting 42% off annual greenhouse gas emissions by 2030 and 57% by 2035 in the next round of NDCs and ensure rapid action or the Paris Agreement’s 1.5°C goal will be history. 

A key focus in Belém will be the latest round of NDCs under the Paris Agreement. Parties were supposed to submit their NDCs by February 2025, but as of the beginning of October 2025, only about a third of Parties to the Paris Agreement had submitted theirs.

At the June Climate Meetings there were calls to provide a space to reflect on these NDCs in Belém and agree on an action package aimed at addressing the expected shortfall in collective ambition. The main question is whether Parties’ NDCs are 1.5°C-aligned, cover all sectors and greenhouse gases, and respond to the calls for energy transition formulated in the decision on the first Global Stocktake. 

Another expectation for this year’s Climate Change Conference is to reach agreement on indicators for measuring progress towards the GGA. Parties are supposed to reach agreement on a set of indicators for measuring progress achieved towards the targets outlined in the 2023 GGA Framework. The indicators are supposed to (a) be globally applicable, (b) capture various contexts of adaptation action, and (c) enable assessment of progress towards the targets and their different components.

In terms of finance, Parties are awaiting the launch of the Presidency’s roadmap to USD 1.3 trillion in Belém, which was mandated in the 2024 decision on the NCQG. With the time to achieve the goal to double adaptation finance from 2019 levels by 2025 running out, developing countries are pushing for a follow-up goal. 

Building on constructive discussions in June, Parties may progress the preparations for the transitioning the Adaptation Fund to exclusively serve the Paris Agreement, now that the building blocks are in place regarding the Agreement’s market mechanisms. As usual, Parties will also debate guidance to the operating entities of the Financial Mechanism, with many especially keen to reflect on progress made in operationalizing the Fund for Responding to Loss and Damage.

Other things to look out for in Belém include:

• agreement on the host of COP 31; 
• the development of a new gender action plan; 
• progress on the just transition work programme;
• negotiations on technology and capacity-building;
• discussions on how to enhance the efficiency of the UNFCCC process; and
• the synthesis report on the first round of biennial transparency reports.

The hope is that COP 30 will help enhance the implementation of ambitious climate action, with engagement from a broad range of actors. However, the withdrawal of the US—the world’s second largest GHG emitter and its largest economy—from the Paris Agreement has consequences for emissions reductions and financing and may compromise other countries’ willingness to step up their climate action. 

The International Court of Justice’s (ICJ) Advisory Opinion on the obligations of states in respect to climate change may also have an impact in Belém, including on the ambition of NDCs. The ICJ found that the Parties to the Paris Agreement have a legal obligation to submit NDCs capable of making an “adequate contribution” to the achievement of the 1.5°C target, and that they must also put in place measures to enable the implementation of these plans. 

In the end, the COP must send a signal that the UNFCCC and the Paris Agreement are fit for purpose. Failure to send this signal could lead to renewed criticisms that the climate regime and the international community continue to fiddle while the planet burns.

Pamela Chasek, Ph.D., is the Co-founder and Executive Editor of the Earth Negotiations Bulletin.