With the COP31 summit set to open shortly there are urgent calls for action after a new United Nations report  warns the world is on the brink of uncontrolled global warming.

Experts have joined calls for the world to move faster and do more to limit temperature rises amid growing impacts of climate change.

The new UNEP report warned with global temperature rise set to exceed 1.5°C above pre-industrial levels, urgent and stringent cuts to greenhouse emissions are needed to minimise the magnitude and duration of overshoot and return to 1.5°C by the end of the century.

The Emissions Gap Report 2026: The Point of Return, looks at a ‘lowest possible’ 1.5°C overshoot scenario, in which peak warming by around the middle of the century is limited to 1.7-1.8°C and global temperature rise is returned to or below 1.5°C by 2100, with about a 50 per cent chance.

To get onto this pathway, global greenhouse gas (GHG) emissions would have to be reduced by 18 per cent by 2030, 45 per cent by 2035 and 69 per cent by 2040, all relative to 2025 levels. By contrast, the full implementation of Nationally Determined Contributions (NDCs) would only reduce emissions by 5-8 per cent by 2030 and 11-15 per cent by 2035, relative to 2025 levels. This implies average annual reduction rates of 5.7 per cent for 2025-2035, higher than the old Sixth Assessment Report (AR6) pathways laid out by the IPCC, which required annual reduction rates of about 5 per cent.

“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,” UN Secretary-General António Guterres said in a message on the report. “The new Emissions Gap Report from the United Nations Environment Programme shows us what it will take: Cutting global greenhouse gas emissions by 18 per cent by 2030 and 45 per cent by 2035 – compared with 2025 levels.”

However, the report finds that there are more opportunities than ever to accelerate action. Since the adoption of the Paris Agreement, renewable energy has boomed, total energy supply from coal and oil has grown slower than projected and climate policies have cut emissions in many places.

“Every additional fraction of a degree and additional year of warming above 1.5°C increases climate impacts and risks, such as the deadly floods, heatwaves and wildfires that have plagued many nations this year,” said Inger Andersen, Executive Director of UNEP. “So, we must pull out all the stops to minimize peak warming and return to 1.5°C by the end of the century. This is possible.

“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, and put the world on track for a more stable climate and more stable economies and societies.”

The report found that if current policies continue, warming could reach 2.8°C within this century and increase thereafter. If all NDCs are delivered and similar efforts continue, warming will be limited to 2.6°C. These outcomes are worse than last year’s projections due to the withdrawal of the United States of America from the Paris Agreement and revised estimates of historical emissions. New NDCs submitted since last year’s report have made a negligible difference for these projections.

Even in the most optimistic scenario, where all NDCs plus additional net-zero targets are achieved, global warming would only be limited to 2.1°C in this century. Without urgent action, keeping peak warming below 1.7 to 1.8°C will quickly become impossible. Every five years of CO₂ emissions at current levels pushes peak warming up by around 0.1°C.

In addition, the lowest possible 1.5°C overshoot scenario creates a need for the removal from the atmosphere and permanent storage of roughly 320 gigatonnes of CO₂ (equivalent to around eight years of 2024’s global CO₂ emissions) over the course of this century. However, socioeconomic and technological challenges make the chances of achieving this uncertain.

The report’s conclusions have prompted renewed calls for action from climate experts.

Ruth Fuller, WWF’s Chief Climate Advisor said: “With COP 31 just days away, this report provides further proof that we are entering ever more dangerous territory. Overshoot of 1.5 needs to be as short and as small as possible. The hotter we get the greater the risks of accelerating tipping points in natural systems, with truly devastating consequences for people and nature.

“We can reduce the risk but only if we act decisively and urgently. At COP 31 countries must seize the opportunity to urgently phase out fossil fuels, invest in climate finance, scale up renewables, accelerate adaptation, restore ecosystems and end deforestation.”

“The main takeaway is simple – governments need to get on with enacting policies that cut fossil fuel use as soon as possible,” said Bill Hare, CEO of the global science and policy institute Climate Analytics.

“We know how to do that: this report is full of options that are proven to work, and our own analysis shows that if governments act with the highest possible ambition, we can halt global warming by mid-century close to 1.7°C and bring it back significantly below 1.5°C by the end of the century.

“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.

“Every fraction of a degree over 1.5°C, every additional year of overshoot guarantees more climate impacts and bigger risks. Recent research shows that for every 0.1 degree warming, another 140 million people are exposed to dangerous heat. The Greenland ice sheet is at risk of irreversible collapse even now. Do the governments and fossil fuel producers of the world really want seven metres of sea level rise and the demise of many entire island countries as their legacy?”