Three UN assessments published in October 2026, ahead of the UN Climate Change Conference (COP31) in Antalya, Türkiye, on 9–20 November, point the same way. The United Nations Environment Programme (UNEP) concludes that limiting warming to 1.5°C without significant overshoot is no longer possible; the UNFCCC secretariat finds that new national pledges would cut emissions by single-digit percentages by 2035; and the World Meteorological Organization (WMO) reports record greenhouse gas concentrations in 2025. This paper sets out what the reports show, where their numbers differ and what this means for the negotiations.
Key points
- Global greenhouse gas (GHG) emissions were 58.4 gigatonnes of CO₂ equivalent (GtCO₂e) in 2025, roughly level with 2024; UNEP says it is too soon to conclude that emissions are plateauing [1].
- To return warming to 1.5°C by 2100 after a peak of 1.7–1.8°C, emissions would need to fall 18% by 2030 and 45% by 2035 from 2025 levels; full implementation of the new nationally determined contributions (NDCs) would deliver 5–8% and 11–15% [1; 2].
- UNEP projects warming of 2.8°C this century under current policies and 2.6°C if all NDCs are delivered, both worse than a year earlier, largely because of the withdrawal of the United States from the Paris Agreement [1; 2].
- The UNFCCC secretariat estimates that the new NDCs put 2035 emissions about 6% below the 2019 level, or about 9% with conditional elements, against the roughly 60% cut that pathways with no or limited overshoot would require [3].
- The atmospheric concentration of CO₂ reached 426.8 parts per million (ppm) in 2025, 53% above the pre-industrial level, and the WMO expects a further rise in 2026 [4; 5].
1. The problem
Under the Paris Agreement, countries set their own targets in NDCs and are expected to strengthen them over time. The current round sets targets for 2035, and COP31 is where its combined effect will be weighed against the science [3; 5].
The question is no longer only whether pledges are large enough. UNEP's 2026 Emissions Gap Report concludes that it is no longer possible to close the gap to a pathway that limits warming to 1.5°C with no or limited overshoot, defined as a temporary exceedance of less than 0.1°C [1]. The benchmark has therefore changed to how high temperatures peak, how long they stay above 1.5°C and whether they can be brought back down.
2. The evidence
Emissions near a plateau, not yet falling. UNEP estimates 2025 global emissions at 58.4 GtCO₂e (range ±5.5), a preliminary decline of 0.1 GtCO₂e from a revised 58.5 GtCO₂e in 2024, but says the direction of change cannot be determined within the uncertainty range [1]. Emissions grew by 0.8% a year over the past decade and 1.7% a year between 1990 and 2016 [1]. Fossil CO₂, nitrous oxide and fluorinated gases rose in 2025, offset by a fall of about 0.5 GtCO₂e in land-use emissions, partly because wildfire emissions were lower than in the exceptionally active 2024 season [1]. G20 members other than the African Union account for 76% of global emissions, and their emissions excluding land use rose 0.7% in 2025 [1]. Over the past decade, 63 countries cut emissions by a combined 1.8 GtCO₂e, while 124 increased them by 7.2 GtCO₂e [1].
More pledges, little more ambition. By 1 September 2026, 124 Parties covering about 76% of global emissions had submitted new NDCs, up from 57 Parties covering 63% a year earlier [1]. Full implementation would cut expected 2035 emissions by 3.5–4 GtCO₂e relative to 2030 NDC levels, an estimate UNEP says is similar to last year's despite more submissions [1]. All G20 members except Argentina, Saudi Arabia and the United States have new NDCs with 2035 targets, and Mexico is the only G20 member to have strengthened its 2030 target [1]. Under current policies, only six G20 members (China, India, Indonesia, the Russian Federation, South Africa and Türkiye) are assessed as likely to meet their unconditional 2030 targets; the assessment for the European Union is inconclusive [1]. UNEP adds that the apparent narrowing of the 2030 implementation gap does not reflect stronger policy but is largely explained by the withdrawal of the United States [1].
The new benchmark. UNEP's "lowest 1.5°C overshoot" scenario, which assumes stringent action from 2025, has a 66% chance of limiting peak warming to 1.7–1.8°C and about a 50% chance of returning warming to 1.5°C by 2100 [1]. It requires cuts of 18% by 2030, 45% by 2035 and 69% by 2040 relative to 2025, an average reduction of 5.7% a year between 2025 and 2035, and the removal and permanent storage of roughly 320 GtCO₂ over the century [1; 2]. The new NDCs would deliver cuts of 5–8% by 2030, 11–15% by 2035 and 20–27% by 2040, leaving a gap of 5 GtCO₂e in 2030 and 16 GtCO₂e in 2035 even if conditional pledges are met [1].
Temperature outlook. With current policies, UNEP gives a 66% chance of limiting warming to 2.8°C by 2100, with temperatures still rising afterwards; full delivery of NDCs gives 2.6°C, and the most optimistic case, in which all NDCs and net-zero targets are met, gives 2.1°C [1; 2]. Every five years of emissions at current levels adds around 200 GtCO₂ to the atmosphere and raises peak warming by about 0.1°C [1].
The UNFCCC's own synthesis. The secretariat's NDC synthesis report, issued on 27 October, covers 127 new NDCs representing 154 Parties, recorded between 1 January 2024 and 31 August 2026 and covering about 71% of global emissions in 2019 [3]. It projects that implementing them would put 2035 emissions, including land use, about 6% (range 0–12%) below the 2019 level, or about 9% (6–12%) with conditional elements [3]. Pathways limiting warming to 1.5°C with no or limited overshoot would need a 60% (49–77%) cut by 2035 from 2019, and below-2°C pathways a 37% cut [3]. With full implementation of conditional elements, global emissions would peak before 2030 [3].
Record concentrations. The WMO Greenhouse Gas Bulletin, also published on 27 October, reports global average concentrations in 2025 of 426.8 ppm for CO₂, 1,948 parts per billion (ppb) for methane and 339.1 ppb for nitrous oxide, all records [4]. CO₂ rose 2.8 ppm from 2024, slower than the exceptional rise of 2023/24 but above the average of the past decade [4; 5]. When the Bulletin was first published in 2004, the level was 377.5 ppm [5]. The WMO expects a further increase in 2026 because of fossil-fuel burning and a developing El Niño that will affect land carbon sinks [5].
3. Analysis
The following assessments are Meridian analysis based on the evidence above.
First, the three reports measure different things and should not be read as contradicting one another. UNEP compares pledges with 2025 emissions and its new overshoot scenarios [1]; the UNFCCC compares them with 2019 [3]; the WMO measures what accumulates in the atmosphere [5]. Even the submission counts differ: 124 Parties and 76% of emissions for UNEP, 154 Parties and 71% of 2019 emissions for the secretariat [1; 3]. The documents do not reconcile these figures, which appear to reflect different cut-off dates, counting methods and base years.
Second, the political centre of gravity has shifted from preventing overshoot to limiting it. By calling no-or-limited overshoot unachievable [1], UNEP has made carbon removal and the speed of cuts after 2030 central to the debate. UNEP itself describes the ability to remove roughly 320 GtCO₂ as uncertain [1], and who would pay for such removal is likely to be contested.
Third, the effect of a single Party's withdrawal is now visible in the numbers. Removing the United States' target from global totals and replacing it with current-policy projections explains both the narrower 2030 implementation gap and part of the higher temperature projections [1; 2]. This is likely to shape what is expected of other large emitters at COP31.
Fourth, real-economy progress is uneven. Renewable electricity capacity grew three times faster than 2015 current-policy scenarios anticipated, and solar photovoltaics seven times faster [1]. Yet total energy supply from coal, oil and gas is still rising; current policies would bring coal to a peak before 2030, while oil and gas use is likely to keep increasing this decade [1]. The COP31 Presidency's proposal to raise global electrification to 35% by 2035, which UNEP assesses as aligned with its lowest-overshoot scenario, is one way to turn these trends into a measurable goal [1].
4. Assessment
- Emissions appear to be levelling off, but they are not yet falling, and concentrations of greenhouse gases continue to rise to new records [1; 4].
- The new NDCs have broadened participation without materially closing the gap [1; 3].
- The benchmark for COP31 is now the size and duration of overshoot, which makes post-2030 cuts and carbon removal central negotiating issues [1].
- Indicators to watch: strengthened 2035 targets at COP31, any new collective milestone such as electrification, new NDCs from Parties yet to submit, and emissions and concentration data during the El Niño.
References
- United Nations Environment Programme, Emissions Gap Report 2026: The point of return – Urgent emissions cuts needed to come back from overshoot of 1.5°C, Executive Summary, Nairobi, 2026, DOI 10.59117/20.500.11822/50038. https://www.unep.org/en/publications/report/emissions-gap-report-2026 (accessed 29 October 2026).
- United Nations Environment Programme, "New UNEP report lays out emission cuts needed for return to 1.5°C", press release, 21 October 2026. https://www.unep.org/en/news-and-stories/press-release/new-unep-report-lays-out-emission-cuts-needed-return-15degc (accessed 29 October 2026).
- UNFCCC secretariat, Nationally determined contributions under the Paris Agreement. Synthesis report by the secretariat, FCCC/PA/CMA/2026/9, 27 October 2026. https://unfccc.int/documents/662393 (accessed 29 October 2026).
- World Meteorological Organization, WMO Greenhouse Gas Bulletin No. 22, 27 October 2026. https://wmo.int/resources/publication-series/greenhouse-gas-bulletin/no-22 (accessed 29 October 2026).
- World Meteorological Organization, "Greenhouse gas levels once again reach record high", press release, 27 October 2026. https://wmo.int/news/media-centre/greenhouse-gas-levels-once-again-reach-record-high (accessed 29 October 2026).