The world can no longer avoid exceeding the 1.5°C warming threshold without significant overshoot, but immediate and sustained cuts in greenhouse gas emissions could still return global temperatures to that level by the end of the century, the United Nations Environment Programme (UNEP) has warned.

In its “Emissions Gap Report 2026: The Point of Return“, UNEP said decades of insufficient climate action had closed the opportunity to limit global warming to 1.5°C with no or only limited overshoot, making a temporary exceedance above the threshold inevitable.

The report, however, said countries could still limit how far temperatures rise above the threshold and how long they remain there, provided governments accelerate emissions reductions and remove large amounts of carbon dioxide from the atmosphere.

Under the report’s lowest-overshoot pathway, global temperatures would peak at 1.7°C to 1.8°C above pre-industrial levels before returning to 1.5°C or below by 2100. The pathway has a 66 per cent chance of limiting peak warming to that range and about a 50 per cent chance of returning temperatures to 1.5°C or below by the end of the century.

To achieve this, global greenhouse gas emissions must fall by 18 per cent by 2030, 45 per cent by 2035 and 69 per cent by 2040, compared with 2025 levels, the report said.

However, current national climate pledges fall far short of these reductions. Full implementation of countries’ new nationally determined contributions (NDCs) would cut global emissions by only 5 to 8 per cent by 2030 and 11 to 15 per cent by 2035, compared with 2025 levels.

The report estimated that the gap between current climate pledges and the lowest-overshoot pathway would reach five gigatonnes of carbon dioxide equivalent in 2030 and 16 gigatonnes in 2035.

Current policies put warming on a higher trajectory

UNEP said global greenhouse gas emissions reached an estimated 58.4 gigatonnes of carbon dioxide equivalent in 2025, a preliminary decline of 0.1 gigatonnes from 2024. However, the uncertainty surrounding the estimate means it is too early to conclude that emissions have peaked or are consistently declining.

Emissions from fossil fuel combustion, nitrous oxide and fluorinated gases continued to rise in 2025, while methane emissions remained almost unchanged. A decline in emissions from land use, land-use change and forestry partly offset these increases.

The report projected that if current government policies continue, there is a 66 per cent chance that global warming will reach 2.8°C by 2100 and continue rising thereafter.

If countries fully implement their current climate pledges and maintain similar efforts, warming could reach 2.6°C. Even in the most optimistic pledge-based scenario, in which countries also meet their long-term net-zero targets, warming would be limited to about 2.1°C this century.

UNEP attributed the deterioration in the pledge-based outlook partly to the United States’ formal withdrawal from the Paris Agreement and revised estimates of historical emissions.

The report said the apparent narrowing of the gap between existing policies and countries’ 2030 targets did not reflect stronger climate action. Instead, it was largely due to the removal of the United States’ climate pledge from global calculations and its replacement with projections based on existing policies.

Climate risks and the case for faster action

The report warned that every additional fraction of a degree and every extra year of warming above 1.5°C increase the risk of irreversible changes to critical Earth systems, including ice sheets, permafrost carbon, ocean circulation and coral systems.

For African countries, which face substantial exposure to extreme heat, droughts, floods and other climate hazards, limiting the extent and duration of warming remains critical to reducing risks to communities, food systems and ecosystems. The report’s global findings underscore the importance of faster emissions reductions alongside adaptation measures to prepare for climate impacts.

UNEP said returning temperatures to 1.5°C by 2100 under the lowest-overshoot pathway would also require removing and permanently storing approximately 320 gigatonnes of carbon dioxide over the course of this century. It cautioned that the feasibility of removing carbon at such a scale remains uncertain because of technological and socioeconomic challenges.

The report also warned that delaying action would make the task harder. Every five years of emissions at current levels adds about 200 gigatonnes of carbon dioxide to the atmosphere and increases peak warming by approximately 0.1°C.

Renewable energy advances offer a pathway

Despite the worsening outlook, UNEP identified progress in renewable energy as evidence that faster climate action remains possible.

Since the adoption of the Paris Agreement in 2015, global renewable electricity capacity has grown three times faster than anticipated under projections based on policies at the time, while solar photovoltaic deployment has expanded seven times faster than expected.

The report said these advances could help countries meet the global goal of tripling renewable energy capacity by 2030 if current trends continue and are supported by additional policies.

However, progress remains insufficient across several key areas. Global energy supply from coal, oil and gas continues to rise, while efforts to reduce methane emissions and halt deforestation remain off track. UNEP said the rate of decline in permanent forest loss must accelerate more than tenfold to meet the global target of halting and reversing deforestation by 2030.

The report called on governments to strengthen climate policies, accelerate the transition away from fossil fuels, improve energy efficiency, reduce non-carbon dioxide emissions and protect forests.

It also urged countries to improve the evaluation of climate policies so governments can identify which measures deliver the greatest emissions reductions and replicate successful approaches across sectors and regions.

UNEP said the opportunity to avoid overshooting 1.5°C had been lost, but the scale and duration of that overshoot would depend on decisions taken now. It stressed that immediate, deeper and sustained emissions cuts remain essential to keeping the Paris Agreement’s long-term temperature goals within reach.