UN declares 1.5°C overshoot 'imminent and unavoidable' — but says return is still possible

For years, the world was told that a heroic effort could still keep global warming within 1.5°C of preindustrial levels. On Wednesday, the United Nations formally closed that door — and immediately pointed to another one.

The UN Environment Programme's Emissions Gap Report 2026, titled 'The Point of Return,' concludes for the first time that breaching the 1.5°C limit set by the Paris Agreement is now 'imminent and unavoidable.' But the report argues that the overshoot can still be kept brief and shallow — and that temperatures can be brought back down to 1.5°C or below by 2100 — if countries act with a speed and scale they have so far refused to match.

We are now saying this window has closed, but we can open it again by making the overshoot as brief as possible. This is about how to find a way back as shortly and as quickly as possible with as limited an overshoot as possible.— Inger Andersen, Executive Director, UN Environment Programme

The report, released ahead of the COP31 climate summit in Antalya, Turkey next month, lays out what that return journey requires: a 18% cut in global greenhouse gas emissions by 2030, 45% by 2035, and 69% by 2040 — all measured against 2025 levels. That works out to average annual reductions of 5.7% over the next decade, a steeper rate than even the Intergovernmental Panel on Climate Change's previous benchmark pathways, which called for around 5% per year, according to UNEP.

Taking the 'lowest possible overshoot' pathway would offer about a 50-50 chance of holding peak warming to between 1.7 and 1.8°C around mid-century before temperatures begin to fall. It would also require removing and permanently storing approximately 320 billion metric tonnes of carbon dioxide from the atmosphere over the course of the century — a scale of carbon removal that has not yet been proven to work, the report notes.

Overshoot is not surrender. We can still keep it as small and as short as possible – and bring temperatures back below 1.5 degrees by the end of the century.— António Guterres, UN Secretary-General

The gap between what is needed and what countries are currently doing is vast. Sticking with existing policies alone could push temperatures up by 2.8°C this century. Full implementation of all current national climate pledges — known as Nationally Determined Contributions, or NDCs — would limit warming to 2.6°C. Even the most optimistic scenario, in which all NDC commitments are met and countries with net-zero targets deliver on them, still produces peak warming of 2.1°C, according to UNEP's projections.

The emissions reductions required under the lowest overshoot pathway are approximately three to four times greater than what current pledges would achieve: under existing NDCs, emissions would fall by only 5–8% by 2030 and 11–15% by 2035, measured against 2025 levels.

UNEP said its projections have deteriorated since last year's report, attributing the worsening outlook in part to the United States withdrawing from the Paris Agreement under President Donald Trump and the country dropping its net-zero emissions goal. Ranked by emissions, the US trails only China globally. According to Climate Change News, report co-author Anne Ohlhoff explained to journalists that because of the US withdrawal, the country's previous national climate target was no longer factored into UNEP's global projections.

All governments have a job to do, but in particular it is time for major fossil fuel producers such as the US and Saudi Arabia, which produce 20-25% of fossil fuels globally, to stop playing politics and face the scientific reality. Right now they are looking at the fire, denying it exists and pouring more petrol on it, while their own citizens increasingly face searing heat, wildfires and other impacts.— Bill Hare, Chief Executive, Climate Analytics

Global greenhouse gas emissions in 2025 reached 58.4 gigatonnes of CO₂ equivalent — a very slight decline from 2024 levels, according to UNEP. But the agency cautioned against reading this as a peak or plateau, citing geopolitical uncertainty and continued heavy reliance on fossil fuels even as renewable energy grows strongly.

Among the findings the report points to as encouraging: renewable electricity capacity worldwide has expanded three times faster than expected since the Paris Agreement was adopted in 2015, while solar photovoltaic deployment has outpaced projections by a factor of seven. Growth in total energy supply from coal and oil has also come in below earlier forecasts. But governments have not translated these trends into the policy commitments needed to close the emissions gap.

The tragedy is that we have the solutions within our grasp. Solar and wind power are growing far faster than anyone expected, yet governments are still failing to move away from fossil fuels quickly enough. The technology is racing ahead while political leadership is dragging its feet.— Mohamed Adow, Director, Power Shift Africa

The report calls for tripling renewable electricity capacity by 2035, phasing out coal by 2040, and dramatically cutting methane — a greenhouse gas 80 times more powerful than CO₂ over the short term. It also calls on countries to cut the share of coal, oil and gas in total energy supply by at least 55%, 15% and 5% respectively by 2035 relative to 2025 levels, with deeper reductions required by 2040.

The report puts a precise figure on the cost of inaction. Each additional five years of CO₂ emissions at today's rates adds roughly 0.1°C to peak warming. University of Pennsylvania climate scientist Michael Mann, who had no role in the UNEP report, told CNN that a rise of 0.1°C in global warming 'permanently cuts global GDP by roughly 1.2% — over $1.2 trillion annually — and pushes approximately 140 million more people into life-threatening, dangerously hot climates.'

If all current national commitments are implemented, global emissions are projected to reach approximately 50 gigatonnes of carbon dioxide equivalent annually by 2035, when they should be below 35 gigatonnes. The science is already clear. Closing that gap is a question of political action, not a lack of scientific evidence.— Johan Rockström, Director, Potsdam Institute for Climate Impact Research

The report arrives at a fraught moment for the international climate architecture. The 'global stocktake' — a Paris Agreement mechanism designed to assess countries' collective progress and scheduled next for 2028 — has been thrown into uncertainty after the IPCC this week failed to set a timetable to publish its next major scientific report before that assessment, according to The Guardian. Rockström urged that the dispute not be permitted to delay action by governments.

The COP31 summit in Antalya next month will launch the second global stocktake process. UNEP says that summit should reaffirm priority mitigation actions, extend quantified emissions goals to 2035 and 2040, and make existing targets more concrete. Whether governments arrive with the ambition the report demands remains, for now, an open question.

Passing 1.5 degrees is a sign that we're not moving fast enough, but it doesn't mean we're doomed.— Kate Marvel, climate scientist, Project Drawdown

Why it matters — The UN's formal declaration that 1.5°C warming is unavoidable resets the terms of global climate diplomacy just weeks before COP31, shifting the central question from whether the target can be met to how much damage can still be prevented — and placing new pressure on every government to dramatically accelerate action.

Reported by unep.org, theguardian.com, sdg.iisd.org, climatechangenews.com, cnn.com, globalissues.org, reuters.com, chinadaily.com.cn