Rabat – The world is likely to cross the 1.5°C global warming threshold within the next few years, but the breach does not have to become permanent, according to a new report from the UN Environment Programme (UNEP).
The report, “Limiting Overshoot,” says the world still has a narrow path to limit the rise, reduce the damage caused by higher temperatures, and eventually bring global warming back below 1.5°C.
UNEP describes this as an “overshoot, peak and decline” pathway. Under this approach, countries would first seek to keep the temperature increase as low and brief as possible, then bring temperatures down through deep emissions cuts and, eventually, net-negative emissions.
The report comes as extreme heat, wildfires and floods continue to expose the consequences of a warmer planet.
“This summer’s scorching heat, raging wildfires and deadly floods are a warning of what lies ahead,” UN Secretary-General António Guterres said.
“We must make the overshoot above 1.5 degrees as small and short as possible. That demands an overshoot of ambition,” he added.
Every fraction of a degree matters
The 1.5°C threshold, set under the Paris Agreement as the most ambitious limit for global warming, is increasingly difficult to maintain.
UNEP’s most optimistic pathway puts peak warming at around 1.8°C above pre-industrial levels. Other possible pathways point to temperatures above 2°C. The higher the peak and the longer the world remains at elevated temperatures, the greater the risks to people, economies and ecosystems.
The consequences could include more severe heatwaves, floods and other extreme weather events, alongside major losses to ecosystems and growing pressure on food and water supplies.
Low-lying coastal areas and Small Island Developing States face particularly serious risks, while cities and critical infrastructure could suffer extensive damage.
The report also warns of a greater possibility of climate tipping points as temperatures rise. These include the destabilization of major ice sheets, further degradation of the Amazon rainforest and disruption of the Atlantic Meridional Overturning Circulation, a major ocean-current system that helps regulate the climate.
Some changes could occur suddenly, while others could build over time and become increasingly difficult to reverse.
“There are no good outcomes if we remain above 1.5°C,” said Inger Andersen, Executive Director of UNEP.
“Across the globe, extreme heatwaves are already proving that climate impacts will strike faster, hit harder, and last longer, costing more lives and causing deeper disruption,” she said.
Emissions cuts remain the priority
UNEP says the most important step is still a rapid and sustained reduction in greenhouse gas emissions.
Countries would need to cut carbon dioxide and methane emissions at a much faster pace, move away from fossil fuels and accelerate the transition to renewable energy.
Such measures could also deliver benefits beyond climate protection, including cleaner air, better public health, lower energy costs and wider access to electricity.
The report stresses that carbon dioxide removal (CDR) can support these efforts but cannot replace them. CDR involves the removal of carbon dioxide from the atmosphere and its long-term storage through methods such as afforestation and other approaches.
UNEP says carbon removal could help return temperatures below 1.5°C only if peak warming stays well below 2°C and countries first make deep cuts to their remaining emissions.
Strict rules would also be necessary to ensure that large-scale carbon removal does not create additional environmental or social problems.
Adaptation must move faster
Even with rapid emissions cuts, the world will have to adapt to climate impacts that are already unavoidable.
UNEP says governments must strengthen resilience in communities, economies and infrastructure while preparing for risks that may prove more severe or unpredictable than current projections suggest.
Measures that can serve both climate mitigation and adaptation should receive particular attention. Nature-based cooling, for example, can help reduce heat in cities while also supporting broader environmental goals.
The report also stresses the importance of climate finance, international cooperation and inclusive policymaking, arguing that countries that bear greater responsibility for climate change should move first and act with greater ambition.
Crossing 1.5°C is not the end point
A temporary breach of 1.5°C would not erase the Paris Agreement goal, but it would carry lasting consequences.
UNEP warns that some losses would remain even if temperatures later fall below the threshold. Some communities could lose their homes or livelihoods, while others may have to relocate or adapt to permanently altered conditions.
Those changes could also raise difficult questions about justice, political power and who bears the cost of climate damage.
“Every fraction of a degree matters, and every year spent in overshoot increases climate risks and the potential for irreversible losses,” said Murat Kurum, President-Designate of COP31.
Kurum said exceeding 1.5°C “should not be seen as a new destination, but as a pathway we must urgently work to minimize and reverse.”
For Australia’s Climate Change and Energy Minister Chris Bowen, the challenge is particularly urgent for vulnerable regions.
“Every fraction of a degree of warming above 1.5 leads to increasing and increasingly severe climate impacts, with our Pacific family standing on the frontlines,” Bowen said.
The UNEP report ultimately presents the 1.5°C overshoot as a warning rather than a surrender. The world may cross the threshold, but how far temperatures rise and how long they stay there will depend on decisions taken now.
“Now is the time we must double down on climate action,” Andersen said. “We can – and must – get on the right path.”
