The vocabulary of the room, in plain language.

Public and private money directed at helping countries and communities prepare for, and cope with, the effects of climate change — flood defences, water management, drought-tolerant agriculture, early-warning systems, resilient infrastructure. It is distinct from mitigation finance, which pays for cutting emissions. Because the benefits are local and often hard to price in a market, adaptation has historically drawn a smaller share of tracked climate finance than mitigation.

Why it matters in the room The balance between adaptation and mitigation finance, and what may be counted as adaptation finance at all, are recurring agenda items. Expect definitional questions — grant versus loan, new versus reallocated, who reports what — to matter as much as headline volumes.

Two lists of Parties attached to the 1992 UN Framework Convention on Climate Change. Annex I contains the industrialised countries and economies in transition as they stood at the time; non-Annex I covers the remaining Parties. Several Convention obligations — particularly on reporting, and on the provision of financial and technological support — were differentiated according to these lists, with Annex II a subset of Annex I carrying specific support commitments.

Why it matters in the room The lists are written into a 1992 treaty and have not been redrawn, while the Paris Agreement organises obligations differently — around nationally determined contributions and common frameworks with flexibility. Knowing which instrument a speaker is arguing under prevents a great deal of talking past one another.

The provision setting out the Agreement’s aim of making finance flows consistent with a pathway towards low greenhouse gas emissions and climate-resilient development. Where the Agreement’s finance articles deal chiefly with support provided to developing countries, Article 2.1(c) concerns the orientation of financial flows in general — public and private, domestic and international. Its precise scope, and how progress against it should be assessed, remain the subject of discussion among Parties.

Why it matters in the room It is the hook that pulls central banks, financial regulation, disclosure rules and development-bank mandates into a climate negotiation. When a delegate moves from “how much money” to “how the financial system is oriented”, this is usually the provision being invoked.

Article 6 of the Paris Agreement provides for voluntary cooperation between countries in meeting their targets. Under Article 6.2, two or more countries may agree to transfer “internationally transferred mitigation outcomes” (ITMOs), subject to accounting rules — the corresponding adjustment — designed to prevent the same reduction being counted twice. Article 6.4 establishes a centralised crediting mechanism, the Paris Agreement Crediting Mechanism, supervised by the Article 6.4 Supervisory Body under the authority of the CMA; Article 6.8 covers non-market approaches.

Why it matters in the room Article 6 is where accounting detail becomes consequential: methodologies, authorisation, registries, corresponding adjustments and transparency of bilateral arrangements. It is also the file where a country’s domestic MRV capacity determines what it can realistically participate in.

The historical year, or period, against which a country measures an emissions target — as in “X per cent below 1990 levels by 2035”. Parties use different base years for legitimate reasons: when reliable inventory data begins, when a domestic law was passed, when a target was first set. Some targets are not expressed against a base year at all, but against a projected business-as-usual pathway, or as an emissions-intensity figure per unit of output or GDP.

Why it matters in the room Two headline percentages are not comparable unless the base year, the gases and sectors covered, and the target type all match. A large share of any technical exchange about ambition is, on inspection, an exchange about baselines.

The principal reporting document each Party to the Paris Agreement submits every two years under the Enhanced Transparency Framework. A BTR carries a national greenhouse gas inventory, information tracking progress towards the country’s NDC and, as applicable, information on climate impacts and adaptation and on support provided, needed or received. First BTRs were due by 31 December 2024; least developed countries and small island developing States may submit at their discretion.

Why it matters in the room The BTR is where a claim becomes checkable. Each report goes through a technical expert review and a facilitative, multilateral consideration of progress, and the reported data is the raw material for the Global Stocktake.

An EU measure that applies a carbon price to the emissions embedded in certain imported goods — at the outset iron and steel, aluminium, cement, fertilisers, electricity and hydrogen — with the stated objective that imported and EU-produced goods face comparable carbon costs (its design and trade-law compatibility are the subject of ongoing discussion among Parties). It opened with a transitional phase from October 2023 in which importers reported embedded emissions without a financial adjustment, and entered its definitive phase, in which authorised declarants surrender CBAM certificates, from 1 January 2026, with the first declaration and surrender of certificates due by 30 September 2027. A carbon price already paid in the country of production can be taken into account, and the rules continue to be refined through implementing legislation and guidance.

Why it matters in the room CBAM makes a producing country’s own carbon pricing and MRV architecture directly relevant to its trade with the EU, which is why the term surfaces in trade, climate and bilateral partnership discussions alike. Most of the technical conversation is about emissions methodology, verified data and administrative capacity.

The concern that emissions-intensive production, and the emissions that go with it, could shift from a jurisdiction with a stricter climate policy to one with a looser policy — so that global emissions fall by less than the first jurisdiction’s national figures suggest. It is the standard analytical justification for design features such as free allocation of allowances, phase-in periods, or a border carbon adjustment. Estimates of its actual size vary considerably by sector and by study.

Why it matters in the room Leakage is the concept that connects climate policy to trade policy. Whenever a design choice needs defending — which sectors are covered, how fast free allocation changes, how a border measure is calibrated — leakage is the frame in which the argument is made.

The Conference of the Parties (COP) is the supreme decision-making body of the 1992 Convention. The CMA is its counterpart for the Paris Agreement — the Conference of the Parties serving as the meeting of the Parties to the Paris Agreement — and the CMP is the equivalent for the Kyoto Protocol. They convene at the same venue in the same period each year, which is why a single annual conference in practice hosts COP, CMA and CMP sessions running in parallel.

Why it matters in the room Mandate decides everything procedural: a decision must be taken by the body competent to take it. Knowing whether an item sits with the COP, the CMA or a subsidiary body tells you who can decide it, on what legal basis, and which Parties are entitled to take part in adopting it.

A market-based instrument in which a government sets a cap on total emissions (some systems instead regulate emissions intensity per unit of output) from covered installations, issues or auctions a matching quantity of allowances, and permits participants to trade them. The cap determines the environmental outcome; trading determines who reduces emissions and at what cost. The resulting carbon price emerges from the market rather than being set administratively, which is the main structural difference from a carbon tax.

Why it matters in the room An operating ETS is directly observable evidence of an explicit carbon price, which is real carbon price — which is relevant to Article 6 cooperation, to any discussion of linking systems, and to border measures that recognise carbon prices already paid.

The common reporting and review system established by Article 13 of the Paris Agreement. It applies to all Parties, with built-in flexibility for those developing countries that need it in the light of their capacities, and it replaced the earlier split arrangements — national communications, biennial reports and biennial update reports — with a single framework delivered mainly through BTRs. Its detailed rules are the modalities, procedures and guidelines (MPGs) adopted by the CMA.

Why it matters in the room The ETF is the regime’s evidence base. The ambition cycle, the Global Stocktake and every finance discussion depend on comparable reported data, so questions of reporting capacity and support for reporting are never purely technical.

A collective assessment, conducted every five years, of progress towards the Paris Agreement’s long-term goals across mitigation, adaptation and means of implementation. It assesses collective progress rather than grading individual countries, and its outcome is intended to inform Parties as they prepare their next NDCs. The first Global Stocktake concluded at COP28 in Dubai in 2023.

Why it matters in the room Stocktake outcome text becomes the shared reference delegations cite afterwards, and agreed language tends to be carried forward into later decisions. Much of the drafting effort therefore goes into wording that will still be quotable years later.

The principle that the shift to a low-carbon economy should take account of the workers, communities and regions whose livelihoods depend on high-carbon activity — through reskilling, social protection, regional investment and social dialogue. The concept draws on International Labour Organization guidelines and is referenced in the preamble to the Paris Agreement. Within the UNFCCC process it has its own dedicated work programme.

Why it matters in the room It is where climate policy meets employment, industrial and social policy, and it widens the delegation: labour ministries, unions and regional authorities have a legitimate claim on the file. It is also the language in which the domestic feasibility of a target is discussed.

“Loss and damage” refers to the impacts of climate change that are not avoided by mitigation or prevented by adaptation — from sudden-onset disasters to slow-onset processes such as sea-level rise, including non-economic losses. The Fund for responding to Loss and Damage (FRLD) was established as an operating entity of the financial mechanism of the Convention and the Paris Agreement and operationalised at COP28; it has its own Board, with the World Bank selected to host its secretariat and to act as trustee. It sits alongside the Santiago Network, which channels technical assistance rather than finance.

Why it matters in the room It is a category of its own, separate from adaptation finance, and conflating the two causes real confusion. The live questions are capitalisation, contributions, eligibility and how quickly funds can actually reach the countries and communities concerned.

A voluntary document, invited under Article 4.19 of the Paris Agreement, in which a country sets out its direction of travel to mid-century: sectoral pathways, technology assumptions, infrastructure choices and investment needs. Unlike an NDC it is not a target with a compliance-relevant deadline; it is a strategy, and countries vary widely in how detailed and how binding they make it.

Why it matters in the room The LT-LEDS gives an NDC its context — the same ten-year target reads very differently depending on the pathway it sits on. Investors, lenders and partner governments read it for signals about where a country intends its energy and industrial system to go.

The generic term for the chain that turns physical activity into a number other people can rely on: measuring or estimating emissions, reporting them in a defined format, and having them checked by someone independent. MRV operates at several levels — national greenhouse gas inventories, installation-level systems under an ETS, and product- or consignment-level data for instruments such as CBAM. Institutional arrangements, data systems and accredited verifiers matter as much as methodology.

Why it matters in the room MRV is unglamorous and decisive. Whether a country can take part in Article 6, demonstrate progress towards its NDC, or have its domestic carbon price recognised elsewhere depends on MRV capacity long before it depends on political will.

The climate plan each Party to the Paris Agreement prepares, communicates and maintains, and submits to a public UNFCCC registry. It is nationally determined: the country chooses the target, its scope and its form, within common accounting and transparency rules and a requirement that each successive contribution represent a progression on the last. Parties communicate new or updated NDCs on a five-year cycle, and many combine an unconditional element with a conditional element dependent on support.

Why it matters in the room The NDC is the unit of account for the whole regime. Transparency, finance, Article 6 and the Global Stocktake all exist to inform, support or track NDCs — so almost every other agenda item eventually resolves into a question about them.

A commitment to reduce emissions and to balance any remaining emissions with removals, so that net emissions reach zero by a stated date. What a particular target actually means depends entirely on its specification: which gases and sectors are covered, whether international aviation and shipping are included, what role removals and international credits may play, what interim milestones exist, and whether the target sits in legislation, in policy, or in a political pledge.

Why it matters in the room “Net zero by year X” conveys very little on its own. The substance is in coverage, the treatment of removals and legal status — which is why the useful question is never whether a country has a net-zero target but how that target is defined.

The two permanent subsidiary bodies of the climate regime: the Subsidiary Body for Scientific and Technological Advice (SBSTA) and the Subsidiary Body for Implementation (SBI). They do the preparatory work — methodological questions, technical guidance, reviews and draft text — that the COP and CMA later consider and adopt. They meet at a mid-year session, traditionally in Bonn, and again during the annual conference.

Why it matters in the room Most substantive drafting happens here rather than in a closing plenary. Text that does not converge in SBSTA or SBI generally arrives at the conference unresolved, which is how technical items end up being settled at political level under time pressure.