Earth Set To Overshoot 1.5°C Limit Within Years, UN Report Warns

The planet is on course to overshoot the critical 1.5°C warming threshold within the next few years, with even the most optimistic scenario based on current national climate pledges pointing to a peak warming of 1.8°C above pre-industrial levels, a new United Nations Environment Programme (UNEP) report has warned.

The findings in the report, Limiting Overshoot, come days after deadly flash floods in Nepal and Tibet following a glacier collapse, highlighting the growing risks associated with a warming planet. More than 1,000 people were killed in the disaster, according to the figures cited in the report.

Glaciers, Sea Levels Face Major Risks

The UNEP said even if countries fully implement their existing national climate plans and meet their net-zero targets, global temperatures could still peak at 1.8°C above pre-industrial levels.

Crossing 1.5°C for a prolonged period would significantly alter ice sheets, sea ice, glaciers, permafrost and snow cover. Glaciers could lose more than a quarter of their mass by 2100, potentially raising sea levels by 9 to 12.5 centimetres and permanently changing water availability in several regions.

The report also warns of faster sea-level rise, more severe heatwaves and wildfires, and a greater risk of ecosystem collapse, including coral reefs.

There is also an increased threat of irreversible tipping points involving major global systems, including the West Antarctic and Greenland ice sheets, the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest.

“There are no good outcomes if we remain above 1.5 degree Celsius,” UNEP Executive Director Inger Andersen said.

“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 added, urging countries to strengthen climate action, resilience and adaptation.

UNEP Calls For ‘Overshoot, Peak And Decline’ Pathway

Despite the warning, UNEP said it is still possible to bring global temperatures back below 1.5°C over time. The report identifies an “overshoot, peak, and decline” pathway as the best remaining option to limit both the scale and duration of warming beyond the threshold.

The strategy would require immediate and sustained cuts in greenhouse gas emissions, including methane, while countries move towards net-zero emissions.

Temperatures could then be brought down through long-term net-negative emissions, supported by carefully governed carbon dioxide removal (CDR). The process involves removing carbon dioxide from the atmosphere and storing it through measures such as afforestation and other carbon-removal methods.

UN Secretary-General Antonio Guterres said the extreme weather witnessed this summer should be treated as a warning.

“This summer's scorching heat, raging wildfires and deadly floods are a warning of what lies ahead,” Guterres said. “We must make the overshoot above 1.5 degrees as small and short as possible. That demands an overshoot of ambition.”

UNEP stressed that there remains uncertainty over exactly when and how strongly individual climate impacts and tipping points could occur. However, it said rapid emissions cuts remain critical to reducing the severity and duration of the overshoot and eventually returning global temperatures below the Paris Agreement threshold.