Earth Set to Overshoot Critical Global Warming Threshold, UN Warns
The world is now expected to cross the 1.5°C global warming threshold – and getting temperatures back down could become one of humanity’s biggest challenges yet.
A new United Nations Environment Programme (UNEP) report says exceeding 1.5°C above pre-industrial temperatures is now widely considered unavoidable, likely within the next few years. For the first time, the focus is shifting from preventing an overshoot entirely to limiting how high temperatures rise, how long they remain elevated, and whether they can eventually be brought back down.
Under UNEP’s most optimistic pathway, global warming would peak at roughly 1.8°C before declining toward 1.5°C later this century. Achieving that would require immediate and sustained reductions in greenhouse-gas emissions, reaching net zero and eventually moving into “net-negative” emissions – removing more carbon dioxide from the atmosphere than humanity releases.
That last step is where the challenge becomes enormous.
Returning temperatures below 1.5°C would likely require carbon dioxide removal on a massive scale, alongside deep cuts in fossil-fuel emissions. Scientists caution that carbon removal cannot substitute for reducing emissions, and deploying it at the scale required would involve major technological, economic, environmental and political hurdles.
And even if temperatures eventually fall again, some damage caused during the overshoot could be permanent. UNEP warns that every additional fraction of a degree – and every additional year above 1.5°C – increases the risks of extreme weather, ecosystem destruction and potentially irreversible tipping points involving ice sheets, the Amazon rainforest and major ocean circulation systems.
The message is no longer simply “stay below 1.5°C”. It is becoming: overshoot as little as possible, stay there for as little time as possible, and prevent a temporary breach from turning into much higher long-term warming.
Source: “Limiting Overshoot: Navigating Exceedance of 1.5°C and Pathways Towards Return”, September 2026, United Nations Environment Programme (UNEP), as cited in Science Explorist
“Fight For Humanity”: Avoiding A Climate Catastrophe Means Acting Now
Record heat waves, deadly flooding and extreme weather reflect an ever-warming planet poised to soon breach safe temperature limits, according to a UN report released on 2 September 2026, but doubling down on climate action now could avoid a climate catastrophe.
The scorching heat in the northern hemisphere in recent months, raging wildfires and deadly floods are a warning of what lies ahead, UN Secretary-General António Guterres said.
He recalled that the historic 2015 Paris Agreement on climate change saw world leaders pledge to keep temperature rise to the 1.5°C limit above pre-industrial levels, which scientists say is critical to avoiding the worst climate devastation.
Indeed, the world is failing to keep that promise, according to the new report from the UN Environment Programme (UNEP).
“The fight for 1.5 degrees is the fight for humanity,” he said. “We are set to breach the 1.5°C limit within the next few years.”
“Every fraction of a degree will cost lives”
There are no good outcomes if temperatures remain above 1.5°C consistently, warned UNEP chief Inger Andersen.
“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.
“Now is the time we must double down on climate action. We can and must get on the right path. By cutting greenhouse gas emissions, strengthening resilience and adaptation and ensuring exceedance of 1.5°C is as small and short as possible.”
The UN chief agreed.
“Every fraction of a degree will cost lives, destroy livelihoods, deepen inequality and push ecosystems closer to irreversible damage,” the Secretary-General said. “Humanity is speeding past the limit to avoid climate catastrophe.”
“Solutions are at hand”
However, swift climate action can bring the world back from the brink, Mr Guterres said.
“We can still bring warming back below 1.5°C by the end of the century,” he said. “We must make the overshoot as small and short as possible, limiting how high temperatures rise and how long they remain above 1.5.”
That demands an “overshoot of ambition” through accelerating the phaseout of fossil fuels and the renewables revolution, slashing methane pollution and protecting land, forest and oceans, he said.
It also means governments must over-deliver on national climate plans, net zero commitments and beyond, and developed countries must triple adaptation finance and ensure it reaches those most at risk.
“The science is clear,” Mr Guterres said. “The solutions are at hand, and the world has never been better equipped to deploy them. Now is the time to raise ambition and accelerate action.”
Highlights from the new report:
● Above 1.5°C, risks and impacts will intensify with every extra fraction of a degree and every year, including intensified extreme weather, ecosystem loss and submersion of small island developing States and low-lying coastal cities alongside severe damage to human health, food security, water supplies, nature, cities, infrastructure and economies.
● The likelihood of crossing irreversible tipping points increases with the magnitude and duration of higher temperatures, including the destabilisation of major ice sheets and degradation of the Amazon rainforest.
● Mitigation and adaptation must advance together, prioritising such interventions as nature-based cooling.
● Net zero is a milestone towards net-negative in sustained reductions in greenhouse gas emissions.
● Conditions for success include strong political will and multilateralism, effective policies, inclusive governance, and finance.
● Countries with greater responsibility for climate change should act the fastest with the greatest ambition.
– from the UN report, ‘Fight for Humanity’: Avoiding a Climate Catastrophe Means Acting Now (2 September 2026)
https://news.un.org/en/story/2026/09/1168240