In a new report, the United Nations Environment Programme (UNEP) says the world is likely to cross the critical 1.5°C global warming threshold within the next few years, but immediate and sustained climate action could still limit the scale and duration of the overshoot.
The report, “Limiting Overshoot – Navigating Exceedance of 1.5°C and Pathways Towards Return,” describes an “overshoot, peak, and decline” pathway as the best remaining option for minimizing how high global temperatures rise and how long they remain above 1.5°C.
According to UNEP, this pathway would require rapid reductions in greenhouse gas emissions, including methane, followed by global net-zero emissions and eventually net-negative emissions. Carefully governed carbon dioxide removal (CDR) would form part of the effort to bring temperatures back down.
The report warns that the higher the peak temperature and the longer the period of overshoot, the greater the risks to people, economies and ecosystems. UNEP therefore emphasizes that crossing 1.5°C should not be interpreted as a reason to abandon the Paris Agreement goal, but as a reason to accelerate climate action.
“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.
Carbon Removal Is Increasingly Part of the Climate Equation
Carbon dioxide removal is gaining importance because emissions reductions alone cannot address all sources of greenhouse gas emissions or remove carbon dioxide that has already accumulated in the atmosphere.
The Intergovernmental Panel on Climate Change (IPCC) has previously found that pathways limiting warming to 1.5°C with limited or no overshoot generally rely on CDR to compensate for residual emissions and, in many cases, achieve net-negative emissions after a temperature peak. The IPCC estimates that these pathways could require roughly 100–1,000 gigatonnes of CO2 removal over the 21st century, while also warning of significant feasibility and sustainability constraints.
Relevant: COP30: Global Warming Projections Remain Stubbornly High Says Report
UNEP similarly stresses that CDR is necessary but is not a silver bullet. Approaches range from conventional methods such as afforestation and improved soil management to newer technologies including direct air capture and carbon mineralization. Each has different costs, scalability, permanence and environmental considerations.
“Emissions reductions alone are not enough to avoid dangerous global heating,” said Dana Jacobs, Chief of Staff at the Carbon Removal Alliance (CRA). “Returning global temperatures to below 1.5ºC this century requires both rapid emission cuts and immediate, scaled deployment of high-quality carbon dioxide removal. Carbon removal is not a theoretical concept or a distant backup plan — it is an active industry with deployable technologies right now. To meet the scale this crisis demands, we must treat carbon removal as an essential requirement today, fund a diverse portfolio of technologies, and establish the clear standards and governance needed to unlock private and public capital.”
The CRA identifies multiple CDR pathways, including direct air capture, mineralization, biomass carbon removal and enhanced rock weathering, reflecting the growing push for a diverse portfolio rather than dependence on a single technology.
What will it take to adopt the UNEP report measures?
UNEP says implementing the overshoot pathway will depend on strong political will, international cooperation, effective policies, inclusive governance and substantial finance. Mitigation and adaptation will also need to progress together, with measures that can deliver benefits in both areas prioritized.
UNEP’s 2025 Emissions Gap Report adds that the world is still far from the emissions reductions required for a 1.5°C pathway and that returning to the target after an overshoot will be extremely challenging.
The message from the latest UN assessment is therefore twofold: crossing 1.5°C may soon become unavoidable, but the extent of the overshoot remains strongly influenced by decisions made today. Rapid emissions cuts, adaptation and responsibly scaled carbon removal will all be needed to keep the eventual temperature rise as low and as temporary as possible.
Read more: COP30: Global Methane Report Says Progress Made But Big Gaps Remain
