Global commitments to cut heat-trapping emissions would limit warming this century to around 2.5°C — far from sufficient to prevent devastating climate impacts, the United Nations warned on Tuesday.
Scientists broadly agree that exceeding 1.5°C above pre-industrial levels risks catastrophic consequences, and every effort must be made to remain as close as possible to this safer threshold.
However, the world is set to surpass 1.5°C within a few years, with greenhouse gas emissions continuing to rise and reaching a record high in 2024, according to a report by the UN Environment Programme (UNEP).
The sobering report was released days before world leaders gather in Brazil for talks ahead of the COP30 climate summit in Belém.
With a 1.5°C overshoot now unavoidable, attention has shifted to how quickly global temperatures can be brought back down.
“Our mission is simple, but not easy: make any overshoot as small and as short as possible,” UN Secretary-General António Guterres said at the launch of UNEP’s Emissions Gap report.
Major polluting nations have been urged to adopt faster and deeper emissions cuts to steer the planet back towards 1.5°C by the end of the century.
Instead, UNEP found that the latest round of pledges “have barely moved the needle.”
“Ambition and action are nowhere near the levels needed globally or collectively,” said Anne Olhoff, the report’s chief scientific editor.
The report projects that, even if all existing commitments are fully implemented, global temperatures will still rise by between 2.3°C and 2.5°C by 2100 — a level that threatens the survival of low-lying and climate-vulnerable nations.
Scientists warn that warming beyond 1.5°C increases not only the severity of extreme weather events but also the risk of triggering irreversible tipping points.
Already, at 1.4°C above pre-industrial levels, most tropical coral reefs are dying, while the Amazon rainforest and polar ice sheets face potentially permanent changes below the 2°C threshold.
Under the Paris Agreement, each new round of national pledges should be more ambitious than the last to keep long-term warming “well below” 2°C and as close as possible to 1.5°C.
Yet by 30 September, only about one-third of countries had submitted updated emissions reduction targets for 2035, UNEP noted.
Although this year’s warming projections are 0.3°C lower than last year’s, Olhoff said most of that improvement was due to updated calculations and new US commitments under President Biden.
These gains could vanish if Donald Trump follows through on his vow to withdraw the United States from the Paris Agreement and scrap his predecessor’s climate policies.
“If we don’t include the US, then the progress is quite limited,” Olhoff warned, describing the outlook as “a very bleak picture.”
Global emissions increased by 2.3% in 2024, driven mainly by India, followed by China, Russia and Indonesia. The G20 economies accounted for three-quarters of total emissions, with the European Union the only major emitter to record a reduction.
Most nations are not even on track to meet their 2030 climate goals, UNEP said. Based on current policies alone, the planet is expected to warm by around 2.8°C by 2100.
As world leaders prepare for COP30, concerns persist that climate action is slipping down the global agenda amid political tensions and competing priorities.
“We still need unprecedented cuts to greenhouse gas emissions, in an ever-shrinking timeframe, and within a challenging geopolitical context,” UNEP Executive Director Inger Andersen wrote in the report.