New report says rapid emissions cuts and stronger adaptation could still limit the duration and severity of global temperature overshoot
By Bunmi Yekini
Global temperatures are likely to rise beyond 1.5 degrees Celsius above pre-industrial levels within the next few years, increasing the risks of extreme weather and irreversible climate damage, the United Nations Environment Programme said in a new report.
The report, Limiting Overshoot, said the world should pursue an “overshoot, peak and decline” pathway aimed at keeping the breach of the Paris Agreement’s 1.5°C target as small and brief as possible before bringing temperatures back below the threshold.
“This summer’s scorching heat, raging wildfires and deadly floods are a warning of what lies ahead,” U.N. Secretary-General Antonio Guterres said in the report.
“We must make the overshoot above 1.5 degrees as small and short as possible.”
UNEP said the most optimistic scenario would see global warming peak at 1.8°C above pre-industrial levels, while most other projections point to even higher temperatures.
Every additional fraction of a degree above 1.5°C would intensify climate risks, including extreme weather, ecosystem destruction, threats to food and water supplies and damage to infrastructure and economies, the report said.
Small island states and low-lying coastal cities also face growing risks from rising seas, while the likelihood of crossing irreversible climate tipping points increases as temperatures remain elevated for longer.
These tipping points could include the destabilisation of major ice sheets, degradation of the Amazon rainforest and disruption of the Atlantic Meridional Overturning Circulation, a major system of ocean currents that helps regulate the global climate.
“There are no good outcomes if we remain above 1.5°C,” UNEP Executive Director Inger Andersen said.
“Extreme heatwaves are already proving that climate impacts will strike faster, hit harder, and last longer – costing more lives and causing deeper disruption.”
The report called for immediate and sustained reductions in greenhouse gas emissions, including methane, alongside a rapid transition away from fossil fuels towards renewable energy.
It said long-term efforts to remove carbon dioxide from the atmosphere could also help bring global temperatures down, but stressed that carbon removal must complement – rather than replace – deep cuts in emissions.
UNEP also called for stronger adaptation measures to protect communities and economies from climate impacts, warning that adaptation would become increasingly difficult and costly if global temperatures continue to rise.
The report said mitigation and adaptation must advance together, with governments prioritising measures that can achieve both goals, including nature-based solutions.
It added that strong political commitment, international cooperation, effective policies and adequate financing would be critical to limiting the scale and duration of the expected temperature overshoot.
Countries with greater historical responsibility for climate change should take faster and more ambitious action, UNEP said, while equity and justice should underpin global climate responses.
The report warned that years of delayed action mean some irreversible losses are now unavoidable, even if temperatures eventually fall below 1.5°C.
Some communities could be forced to relocate or change their livelihoods as societies adapt to permanently altered environmental conditions, it said.
Chris Bowen, Australia’s minister for climate change and energy and president of negotiations for COP31, said the upcoming climate summit offered an opportunity to translate growing momentum into action.
Türkiye’s COP31 President-Designate Murat Kurum said exceeding 1.5°C should not become “a new destination” but a threshold that countries must urgently work to minimise and reverse.
“The choices we make today will determine how high temperatures peak, how long they remain there, and how safely we can return to 1.5°C,” Kurum said.