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This month, negotiators gather for the COP31 climate summit in Antalya, Türkiye. Australia's Climate Change Minister Chris Bowen presides over the formal talks.[7]
Two findings reshape the debate.
Warming has accelerated, and the United Nations Environment Programme (UNEP) now calls a temporary breach of 1.5°C unavoidable.
Overshoot describes warming that exceeds 1.5°C and later returns below it.[8]
Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research (PIK) and Grant Foster tested five temperature datasets.
They removed El Niño, volcanic eruptions and solar variation, the natural fluctuations that mask long-term trends.
Two statistical tests then found acceleration at above 98 per cent confidence in every dataset.[9]
Over the past decade, warming has averaged about 0.35°C per decade. Between 1970 and 2015, the average stayed just under 0.2°C. The team reports the first statistically significant detection of acceleration in the warming trend.[1]
If that rate persists, the long-term 1.5°C threshold arrives between 2026 and 2029. The Paris Agreement judges the limit across about 20 years, so 2024 alone fell short of a breach. Claudie Beaulieu, whose 2024 study found no detectable surge, warns the acceleration may prove temporary.[9]
Scientists dispute the finding's strength. Michael Mann of the University of Pennsylvania sees a roughly constant warming rate. Zeke Hausfather calls the adjustment imprecise and points to falling sulfur dioxide pollution as the likeliest driver.[9]
UNEP issued its Emissions Gap Report 2026, The Point of Return, on October 21. The report concludes that limiting warming to 1.5°C with limited overshoot is no longer possible. The Netherlands Environmental Assessment Agency (PBL) played a pivotal role in the modelling.[2]
Global emissions reached 58.4 billion tonnes of carbon dioxide equivalent in 2025. That unit converts every greenhouse gas into carbon dioxide's warming effect. Emissions now sit about 80 per cent above the level that limited overshoot required by 2030.[8]
The best remaining scenario peaks near 1.7°C to 1.8°C around mid-century. It then returns to 1.5°C by 2100 with a 50 per cent chance. Without urgent action, even that narrow path will quickly close.[2]
UNEP says older pathways from the Intergovernmental Panel on Climate Change (IPCC) assumed cuts from 2020 and have become outdated. Every five years of delay locks in another 0.1°C of warming. The task now is to minimise the size and scale of the overshoot.[8]
The lowest-overshoot pathway demands global cuts of 18 per cent by 2030 and 45 per cent by 2035. Cuts then reach 69 per cent by 2040. Each figure compares with 2025 emissions.[2]
Nationally Determined Contributions (NDCs), the climate pledges each country lodges under the Paris Agreement, deliver far less. Full implementation cuts only 5 to 8 per cent by 2030 and 11 to 15 per cent by 2035. UNEP also says coal-fired electricity must fall at least 75 per cent by 2035 and effectively end by 2040.[3]
Staying on the lowest-overshoot path needs global emissions to fall 5.7 per cent a year over the next decade. UNEP notes that pace outstrips the 5 per cent annual cut needed had action begun in 2019. A below-2°C pathway demands 11, 24 and 37 per cent cuts by 2030, 2035 and 2040.[8]
Current policies point to 2.8°C of warming this century, and full NDC delivery still reaches 2.6°C. Adding every net-zero pledge lowers the figure only to 2.1°C. Renewable capacity has grown three times faster than anticipated since the Paris Agreement, which shows faster progress is possible.[2]
The lowest-overshoot route also needs carbon dioxide removal (CDR), pulling roughly 320 gigatonnes from the air this century. A gigatonne equals one billion tonnes, so that total matches about eight years of 2024 emissions. UNEP calls that task a huge effort.[2]
Removal today totals about 2.2 gigatonnes a year, almost all from forests. Researchers say it must reach 8.8 gigatonnes by 2050. Novel technologies supply under 0.1 per cent of current removals.[4]
Forests compete with agriculture for land and risk releasing stored carbon through fire and disturbance. Ocean modelling shows upper-ocean temperatures would stay flat for at least 30 to 40 years after surface temperatures fall. Researchers also flag large uncertainty over how well novel technologies would work at scale.[4]
UNEP's September report, Limiting Overshoot, links every extra year above 1.5°C to rising risk. Hazards include faster sea-level rise, coral reef collapse, more extreme heat and wildfire, and ice sheet tipping points. Returning below 1.5°C would leave some of that damage in place.[5]
The federal government's November 2025 projections show Australia has cut emissions 28.5 per cent since 2005. They reach 42 per cent by 2030, one point short of the legislated 43 per cent target. Emissions fell 2.2 per cent in the latest annual figures.[6]
For 2035, the projections reach 48 per cent against a target range of 62 to 70 per cent. Minister Bowen told parliament that a gap between projections and a decade-away target is normal. The Climate Change Authority recommended that range in September 2025, and Prime Minister Anthony Albanese accepted it.[6]
On November 3, 503 Australian academics wrote to the Prime Minister. They argued that Australia lacks credibility to lead abroad while expanding coal and gas at home. Signatories include Climate Change Authority board member Lesley Hughes and climate scientist David Karoly.[7]
The letter seeks a ban on new fossil fuel projects, including those in the Hunter Valley and Beetaloo. Federal approval for the Hunter Valley Operations extensions remains pending. Anne Poelina, an Indigenous knowledge researcher, wants the Prime Minister to hear frontline communities opposing a Kimberley fracking proposal.[7]
The evidence converges on one conclusion. Warming has quickened, the 1.5°C limit will give way, and the task now is to shrink and shorten the overshoot.
UNEP has published the arithmetic of cuts and removals. Australian projections still fall well short of the 2035 target, while new coal and gas approvals await federal decisions. Each approval shapes the height and length of the peak.
Accountability starts at COP31, where Australia presides over the negotiations. Credible leadership needs policies that match the targets, honest reporting of gaps and a hearing for frontline communities. First Nations and frontline voices belong at the centre of that reckoning.
1. Significant acceleration of global warming since 2015. Potsdam Institute for Climate Impact Research release on the Geophysical Research Letters study by Foster and Rahmstorf.
2. UNEP Emissions Gap report 2026. Summary from the Netherlands Environmental Assessment Agency, lead modeller of the report, including removal needs and warming scenarios.
3. New UNEP report lays out emission cuts needed for return to 1.5°C. UNEP press release on the Emissions Gap Report 2026, covering required cuts, pledge shortfalls and temperature projections.
4. Experts: Why carbon removal needs a 'major scale up' to return warming to 1.5C. Carbon Brief report from the Milan conference on the scale, limits and policy needs of carbon dioxide removal.
5. The UN Environment Programme warns world will overshoot 1.5°C, but return remains possible. Mail & Guardian summary of UNEP's Limiting Overshoot report and its warnings on tipping points and lasting damage.
6. Australia projected to fall short of its 2035 climate target. The Daily Aus account of the federal emissions projections released in November 2025 against the 2030 and 2035 targets.
7. Australia cannot 'credibly lead' COP31 without reform. AAP report on the open letter from 503 academics to the Prime Minister days before COP31.
8. UNEP: Opportunity has 'been lost' to meet 1.5C warming limit without 'overshoot'. Carbon Brief's detailed coverage of the report's pathways, annual reduction rate and cost of delay.
9. Pace of global warming has nearly doubled since 2015, reveals study. Carbon Brief analysis of the study's method, five datasets, breach window and expert disagreement.
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