NAIROBI: The world is on course to exceed the 1.5°C global warming threshold in the coming years, but humanity can still limit the scale and duration of the overshoot and eventually bring temperatures back below the landmark Paris Agreement goal, according to a new United Nations Environment Programme (UNEP) report.
The report, “Limiting Overshoot: Navigating Exceedance of 1.5°C and Pathways Towards Return,” says exceeding 1.5°C is now widely assessed as unavoidable under current policies and near-term emissions trajectories.
However, UNEP stresses that crossing the threshold must not be seen as a reason to abandon climate action. The lower the peak temperature and the shorter the period spent above 1.5°C, the lower the risks to people, economies and ecosystems.
UN Secretary-General António Guterres warned that recent extreme heat, wildfires and floods are a sign of what lies ahead and called for the overshoot to be kept “as small and short as possible.”
Under the most optimistic pathway examined by UNEP, global warming could peak at around 1.8°C above pre-industrial levels before declining. Other pathways indicate substantially higher levels of warming.
The report warns that every additional fraction of a degree above 1.5°C can intensify climate risks, including extreme weather, ecosystem degradation, threats to food and water security, infrastructure damage and impacts on human health.
It also highlights growing concerns over climate tipping points, including destabilization of major ice sheets, degradation of the Amazon rainforest and disruption of major ocean circulation systems. The likelihood of crossing such potentially irreversible thresholds increases as warming becomes higher and lasts longer.
UNEP says the world must pursue an “overshoot, peak and decline” pathway based on rapid and sustained greenhouse-gas emissions reductions, reaching net-zero emissions and eventually achieving net-negative emissions. Carefully governed carbon dioxide removal, including afforestation and other approaches, could play an important role in bringing temperatures down after the peak.
At the same time, countries will need to strengthen climate adaptation and resilience to cope with impacts that are already occurring and those expected in the coming decades.
The report emphasizes that going beyond 1.5°C does not mean the climate battle is lost. UNEP notes that every fraction of a degree of warming avoided reduces climate risks, while every year by which the overshoot is shortened reduces exposure to worsening impacts.
The message is therefore not resignation but urgency: governments must accelerate emissions cuts, expand renewable energy, strengthen resilience and protect vulnerable communities while keeping the possibility of returning below 1.5°C within reach.
