UN report says world may overshoot 1.5°C but can still return via emissions cuts and removal

The world is set to cross the 1.5°C global warming threshold, likely within the next few years, exposing people and ecosystems to increasingly dangerous climate impacts, according to a new UN Environment Programme (UNEP) report. However, it says temperatures can still be brought back below the threshold and the goals of the Paris Agreement achieved.The report, Limiting Overshoot, identifies an "overshoot, peak and decline" pathway as the best remaining option. Under this approach, temperatures would temporarily exceed 1.5°C, peak and then decline as countries rapidly cut greenhouse gas emissions and eventually remove more carbon dioxide from the atmosphere than they emit.A Narrower Climate Path"This summer's scorching heat, raging wildfires and deadly floods are a warning of what lies ahead. We must make the overshoot above 1.5 degrees as small and short as possible. That demands an overshoot of ambition," UN Secretary-General António Guterres said.The pathway requires immediate and sustained reductions in greenhouse gas emissions, including methane, on the road to net-zero emissions. Carbon Dioxide Removal (CDR), which removes carbon from the atmosphere and stores it through afforestation or other means, would also be essential to eventually bring temperatures down.Every Fraction MattersCountries would simultaneously need to strengthen adaptation to reduce the vulnerability of societies, communities and economies. UNEP cautions that adaptation has limits and some impacts are likely to be irreversible, particularly if peak temperatures are not kept as low as possible."There are no good outcomes if we remain above 1.5°C. 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," UNEP Executive Director Inger Andersen said.Even Best Case Hits 1.8°CUnder the most optimistic scenario examined in the report, temperatures would peak at 1.8°C above pre-industrial levels, already higher than the Paris Agreement goal of limiting warming to 1.5°C. Most other scenarios foresee higher peaks.Every additional fraction of a degree and every year spent above 1.5°C would intensify risks. Expected impacts include more severe extreme weather, ecosystem loss and the submersion of Small Island Developing States and low-lying coastal cities. Human health, food security, water supplies, infrastructure and economies would also face severe damage.Tipping Points LoomUNEP warns that the likelihood of crossing irreversible climate tipping points increases depending on how high temperatures rise and how long they remain elevated. Potential tipping points include destabilisation of major ice sheets and degradation of the Amazon rainforest.The report also warns of possible disruption to the Atlantic Meridional Overturning Circulation, a system of ocean currents that plays an important role in regulating the climate. Some climate impacts could emerge abruptly, while others would accumulate over time.Faster Shift From Fossil FuelsThe report calls for accelerated global action, pointing to the wider benefits of rapidly moving from fossil fuels to renewable energy. Such a transition could improve air quality and public health, lower energy costs and increase access to electricity.Strong political will, multilateral cooperation, effective policies, inclusive governance and finance will be essential. Equity and justice must underpin climate responses, with countries bearing greater responsibility for climate change expected to act faster and with greater ambition.Net-Zero Is Not The Finish LineMitigation and adaptation must advance together because they reinforce each other. UNEP recommends measures that can achieve both goals, including nature-based cooling, while warning that adaptation must respond to evolving and abruptly emerging risks.The report says net-zero emissions should be viewed as a milestone towards net-negative emissions rather than the final destination. CDR would be required in addition to sustained cuts in greenhouse gas emissions, not as a substitute for them.Carbon Removal Has LimitsCarbon removal can credibly help return temperatures below 1.5°C only if peak warming remains well below 2°C and residual emissions are reduced. Strong governance frameworks would also be needed to ensure responsible deployment and address environmental integrity, equity and scale.Even successfully bringing warming back below 1.5°C would not undo all the damage. Years of insufficient action mean irreversible losses and permanently changed conditions are certain, according to the report.Communities Face Lasting ChangeSome communities could be forced to relocate or change their livelihoods, while societies would have to adjust to changed conditions. This would raise difficult questions involving justice, power and political legitimacy, requiring new and inclusive governance arrangements.Australian Minister for Climate Change and Energy and COP31 President of Negotiations Chris Bowen said every fraction of warming above 1.5°C would bring increasingly severe impacts, with Pacific communities on the frontlines. He said the energy crisis had reinforced the need to reduce dependence on fossil fuels, accelerate the renewable energy transition and strengthen climate cooperation.COP31 Faces A Crucial TestBowen said COP31 offered an opportunity to turn ambition into action, with Türkiye, Australia and the Pacific seeking a practical, solutions-focused conference.COP31 President-Designate Murat Kurum said exceeding 1.5°C should not be treated as a new destination but as a situation that must urgently be minimised and reversed. Every year spent in overshoot, he said, increases climate risks and the possibility of irreversible losses.Action Cannot WaitKurum called for faster global electrification, reductions in methane emissions from waste, stronger climate resilience in cities and greater protection for marine and coastal ecosystems. He said today's decisions would determine how high temperatures peak, how long they remain there and how safely the world can return to 1.5°C.The report's central warning is stark: the world may no longer be deciding simply whether it crosses 1.5°C, but how far beyond that threshold it goes and for how long. UNEP says immediate action is required to keep an "overshoot, peak and decline" pathway, and an eventual return below 1.5°C, within reach. 

The United Nations outlined Wednesday how the world might bring global temperatures back to 1.5C once the milestone target is breached in a first-of-its-kind assessment that drew criticism from climate activists.UN Secretary General Antonio Guterres last year acknowledged the inevitability of overshooting 1.5C but this is the first time a UN agency has addressed this head-on in a dedicated report.Scientists agree that warming above 1.5C relative to pre-industrial times poses grave risks and nearly 200 nations committed in 2015 to try and keep global temperature rises to this safer threshold.Also read: As climate change warms the Himalayas, disasters like the Nepal floods are becoming more frequentBut the world is expected to blow past 1.5C in a matter of years and attention has pivoted to making any "overshoot" as brief and contained as possible.In a much-anticipated report, the UN Environment Programme (UNEP) stated unequivocally that 1.5C would be surpassed and "the challenge has shifted from avoiding overshoot to navigating it"."It's a reality check. We have to live with this warmer world... but there's still a lot we can do to limit warming," said report co-author Richard Betts from the University of Exeter.The report "was about responses rather than just sort of saying it is happening", he told journalists.Fellow author Debra Roberts said it was important for policymakers "to realise the rules of the game are now changing"."I think for me that's the clarion call... we now have to reconfigure our climate governance around dealing with an overshoot pathway. None of our plans are prepared for that," said Roberts from the University of KwaZulu-Natal.Also read: One Indian among 12 killed in Russian strikes on Ukraine says President ZelenskyyDismayThe report's stark language alarmed climate campaigners who have rallied around 1.5C since it was affirmed as the more ambitious goal of the Paris Agreement a decade ago."This is a heartbreaking moment, but overshoot is not the reason to give up and surrender 1.5C", said Jasper Inventor, Deputy Programme Director at Greenpeace International.Bill Hare, a climate scientist and CEO of policy institute Climate Analytics, slammed the report and said it risked becoming "a call to apathy rather than a call to arms".Small island nations threatened by rising seas have been particularly vocal defenders of the 1.5C target and have urged wealthier countries not to abandon the milestone even as it slips out of reach.The world has already warmed roughly 1.4C since 1850-1900 mostly from the burning of fossil fuels and the last three years have been the hottest on record.No good outcomesScientists say any overshoot of 1.5C threatens more extreme weather and pushes the planet closer to tipping points like the collapse of ice sheets and loss of coral reefs.UNEP executive director Inger Andersen said there "are no good outcomes if we remain above 1.5C". "Let's be very clear - that 1.5C target is still the goal. But now, we need to approach it differently: from above," Andersen told journalists.Guterres it was possible to bring warming back below 1.5C by the end of the century."The fight for 1.5 degrees is the fight for humanity," he said.To achieve this, carbon dioxide removal - the process of pulling carbon from the air and storing it - would be essential alongside deep and rapid cuts to greenhouse gas emissions, the UNEP report said.At present, carbon removal plays a vanishingly small part in addressing climate change and is strongly opposed by many activists pushing for a faster phase out of coal, oil and gas."The only way to minimise harm is to cut emissions now... not to delay action with speculative techno-fixes," said Lili Fuhr from campaign organisation CIEL.