A new report is warning that accelerating ice sheet and glacier loss will cause irreversible impacts if the world overshoots the Paris Agreement target to limit global warming to 1.5°C.

Produced by the International Cryosphere Climate Initiative (ICCI) in coordination with the UN Environment Programme (UNEP), Overshoot and the Cryosphere: Averting Global Meltdown says exceeding the 1.5°C target will bring large and in many cases irreversible impacts from the Earth’s melting ice sheets, permafrost, glaciers, sea ice and polar oceans.

However, the losses can still be limited if overshoot is kept to a minimum by deep emissions reductions followed by scaled-up carbon drawdown. The report sets out the global impacts of ice loss with overshoot, exploring which ones are locked in – and how more urgent climate action can still stop or slow the worst of this damage, delivering vital evidence ahead of COP31 in Türkiye.

The report, which brings together an international team of over 80 polar and mountain scientists, lays out out actionable solutions to bring temperatures back down from overshoot.

Renewable energy and battery technologies are booming, reliance on coal and oil is slowing, and climate policies have cut emissions in many places. Successful policies now need to be scaled up to reduce emissions by at least 5% per year, starting now, reaching net zero greenhouse gas emissions by mid-century.

The report emphasizes that there can be no delay in phasing out fossil fuels to retain the possibility of bringing temperatures down in the future by drawing down carbon.

Doing so will have tangible benefits for future generations including:

• Slowing down the rate of sea-level rise to an ‘adaptable’ level. Even though several meters of sea level rise are already locked in for many centuries due to the long-term retreat of polar ice sheets, how fast it will happen matters greatly to coastal communities on the frontline of climate change today.
• Potentially halting and partially reversing glacier, snowpack and sea ice loss. A return to 1.5°C and below would initiate some sea ice and glacier re-growth within decades to centuries, and potentially re-establish healthy snowpack levels.
• Limiting the damage from impacts such as the destabilization of permafrost, which can lead to tragic events such as that seen in Nepal and also emits carbon as it thaws. This climate feedback loop would leave even more CO2 to be removed from the atmosphere later.

The report serves as a thematic companion report to UNEP’s Limiting Overshoot Spotlight Report, published in September 2026, the first of its kind from a UN agency.

Overshoot and the Cryosphere was jointly released with the latest instalment of the similarly peer-reviewed State of the Cryosphere 2026: The Cost of Overshoot on November 2, 2026.

The two reports set out the global impacts of ice loss with overshoot, exploring which ones are locked in, and how urgent action – especially the transition from fossil fuels – can still stop or slow the worst of this damage. Overshoot must be kept to the absolute minimum and temperatures returned to below 1.5°C as quickly as possible.

Current levels of warming are already unsafe for the Arctic, the Antarctic, mountain glaciers and the polar oceans. State of the Cryosphere 2026 describes new science and observations from the past year, such as Switzerland’s loss of 20% of its glacier ice in the past five years. Other impacts range from accelerating sea-level rise due to rapid ice loss, to increasing water shortages and mountain hazards as glaciers disappear and snow drought conditions spread.

Although returning to 1.5°C will slow ice loss, a truly ‘safe’ temperature target for Earth’s ice is now thought to be closer to 1.0°C or even below over the coming centuries.