World can no longer avoid exceeding 1.5C threshold - UN

The world has lost the opportunity to prevent global warming significantly exceeding the critical threshold of 1.5C above pre-industrial levels, according to a major new UN report.

Decades of inadequate action to reduce greenhouse gas emissions mean that a significant overshoot of the temperature limit is now unavoidable.

The international community faces the much greater challenge of limiting the extent and duration of further warming and eventually bringing global temperatures back down.

The UN Environment Programme (UNEP) has said global emissions would now need to fall by 18% by 2030, 45% by 2035 and 69% by 2040, compared with 2025 levels, to keep warming to the lowest achievable overshoot of 1.5C.

However, even if governments fully implement their existing national climate commitments, emissions are expected to decline by just 11% to 15% by 2035.

The findings are contained in UNEP's annual Emissions Gap Report 2026, entitled The Point of Return, published ahead of next month's COP31 climate summit in Antalya, Turkey.

The report concludes that the lowest achievable overshoot scenario would see global temperatures peak at between 1.7C and 1.8C above the threshold around the middle of this century.

UN Secretary-General António Guterres said the world could no longer avoid overshooting 1.5C but insisted this did not mean abandoning the Paris Agreement's temperature ambitions.

"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 necessary emissions reductions would amount to almost 6% every year until 2035.

"The emissions gap is now a leadership gap," he said.

"And the world is running out of time and excuses to close it."

UNEP estimates that a continuation of existing government climate policies would result in global warming reaching approximately 2.8C this century.

Even if countries fully implement their national climate pledges, warming would still reach approximately 2.6C.

Both projections have deteriorated since last year's assessment, partly because of the withdrawal of the United States from the Paris Agreement and revisions to historical emissions estimates.

UNEP says new climate commitments submitted by governments since its previous report have made a negligible difference to the projected temperature outcome.

Even under its most optimistic scenario, in which all national pledges and additional long-term net-zero commitments are achieved, warming would still reach approximately 2.1C.

UNEP Executive Director Inger Andersen warned that every additional fraction of a degree of warming, and every additional year spent above the 1.5C threshold, increased the risk 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.

The report calculates that every further five years in which global CO2 emissions remain at current levels would increase peak warming by approximately another 0.1C.

It also concludes that returning global temperatures to 1.5C above pre-industrial levels following an overshoot would require the removal and permanent storage of approximately 320 billion tonnes of carbon dioxide from the atmosphere over the course of this century.

That is equivalent to around eight years of global CO2 emissions at 2024 levels.

However, UNEP acknowledges considerable uncertainty about whether carbon removal on this scale can eventually be achieved.

Despite its increasingly stark assessment, the report identifies evidence that the transition to cleaner energy is accelerating and government climate policies are delivering measurable emissions reductions.

Since the Paris Agreement was adopted, renewable electricity capacity has expanded three times faster than anticipated, while solar deployment has increased seven times faster than projected.

Renewable electricity generation overtook coal-fired generation globally for the first time in 2025.

However, global greenhouse gas emissions have still not definitively peaked, while progress in reducing fossil-fuel consumption, methane emissions and deforestation remains inadequate.

The report says coal-fired electricity generation would need to fall by at least 75% by 2035 and be effectively phased out globally by 2040 to remain consistent with its lowest achievable 1.5C overshoot scenario.

The findings present a major challenge for governments preparing to attend COP31 next month.

Mr Guterres called on the G20 countries to lead, while urging developed nations to provide affordable finance to help developing economies accelerate their energy transitions.

He also called for credible roadmaps for transitioning away from fossil fuels, with clear timelines and protection for affected workers and communities.

Ms Andersen said there was already substantial evidence that effective climate policies could deliver rapid reductions.

"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.