The chance to stop global warming from surging well past the 1.5C guardrail has slipped away, a major new UN assessment warns, after years of stalled progress on cutting greenhouse gas emissions.
Decades of inadequate action mean the world is now locked into a significant overshoot of the critical temperature threshold above pre-industrial levels.
That shifts the task facing governments: instead of preventing the breach, the focus must now be on limiting how far and how long temperatures rise — and ultimately driving them back down.
The UN Environment Programme (UNEP) said emissions would now have to fall by 18% by 2030, 45% by 2035 and 69% by 2040, compared with 2025 levels, to hold warming to the lowest achievable overshoot of 1.5C.
Yet even if governments deliver in full on the national climate commitments already on the table, UNEP projects emissions would drop by only 11% to 15% by 2035.
The analysis is set out in UNEP’s annual Emissions Gap Report 2026, titled The Point of Return, released ahead of next month’s COP31 climate summit in Antalya, Turkey.
COP31 will take place in Antalya, Turkey, next month
Under the report’s lowest achievable overshoot pathway, global temperatures would crest at between 1.7C and 1.8C above the 1.5C threshold around the middle of this century.
UN Secretary-General António Guterres said avoiding an overshoot is no longer possible, but argued that the Paris Agreement’s temperature goals still matter — and still require urgent action.
“Overshoot is not surrender. We can still keep it as small and as short as possible – and bring temperatures back below 1.5C [above pre-industrial levels] before the end of the century,” he said.
Mr Guterres said the scale of effort implied by UNEP’s pathways would require emissions cuts of almost 6% every year through 2035.
“The emissions gap is now a leadership gap,” he said.
“And the world is running out of time and excuses to close it.”
UN Secretary-General António Guterres said the overshoot is ‘not surrender’
On current trajectories, UNEP estimates, global warming would reach about 2.8C this century if governments simply stick with existing climate policies.
Even with full implementation of national climate pledges, the report says temperatures would still climb to around 2.6C.
UNEP notes both projections are worse than last year’s, attributing the deterioration in part to the United States withdrawing from the Paris Agreement and to revisions in estimates of historical emissions.
New climate commitments submitted since UNEP’s previous assessment have barely moved the dial, the report adds, making a negligible difference to the overall temperature outlook.
Even in the most optimistic scenario assessed — where all national pledges are met and additional long-term net-zero commitments are achieved — warming would still reach roughly 2.1C.
UNEP Executive Director Inger Andersen warned that each fraction of a degree matters, and that every extra year above 1.5C compounds the danger of severe climate impacts.
“So, we must pull out all the stops to minimize peak warming and return to 1.5C by the end of the century. This is possible,” she said.
UNEP’s calculations also underline the cost of delay: every additional five years of global CO2 emissions holding at current levels would push peak warming up by about another 0.1C.
UNEP Executive Director Inger Andersen warned of increased impacts of climate change
The report says reversing an overshoot — returning global temperatures to 1.5C above pre-industrial levels — would require the removal and permanent storage of around 320 billion tonnes of carbon dioxide from the atmosphere over the course of this century.
That amount is roughly equivalent to eight years of global CO2 emissions at 2024 levels.
But UNEP cautions that there is significant uncertainty over whether carbon removal at that scale can be delivered.
Despite its increasingly stark conclusions, the report points to signs that the energy transition is gaining speed and that climate policies are producing measurable emissions cuts.
Since adoption of the Paris Agreement, renewable electricity capacity has grown three times faster than expected, while solar deployment has expanded seven times faster than projected.
In 2025, renewable electricity generation surpassed coal-fired generation worldwide for the first time.
Even so, the report stresses that global greenhouse gas emissions have not conclusively peaked, and that efforts to curb fossil-fuel use, methane pollution and deforestation remain insufficient.
To align with the lowest achievable 1.5C overshoot scenario, UNEP says coal-fired electricity generation would need to drop by at least 75% by 2035 and be effectively eliminated worldwide by 2040.
Those conclusions raise the stakes for governments heading to COP31 next month.
Mr Guterres urged G20 nations to take the lead, while calling on developed countries to provide affordable finance so developing economies can speed up their own energy transitions.
He also pressed for credible, time-bound roadmaps to move away from fossil fuels, including protections for workers and communities likely to be hit hardest by the shift.
Ms Andersen said examples from around the world already show that strong climate policies can drive steep cuts in a short period of time.
“We have a wealth of success stories showing that emissions can be cut quickly. It is now up to nations to urgently put in place policies that spark fast, deep and sustained emissions reductions,” she said.
