UN-backed reports warn of ‘irreversible’ damage to glaciers, ice sheets from global warming

Exceeding the 1.5C warming threshold could trigger irreversible damage to Earth’s ice systems, accelerate sea-level rise and threaten water supplies worldwide, two UN-backed reports warned Monday. “Overshooting the 1.5C Paris Agreement target will bring large-scale, and in many cases irreversible, impacts from the Earth’s melting ice sheets, permafrost, glaciers, sea ice and polar oceans,” they said. The reports, released with the involvement of the International Cryosphere Climate Initiative (ICCI) and the UN Environment Programme (UNEP), highlighted the growing risks posed by melting glaciers, polar ice sheets, sea ice and thawing permafrost.

The State of the Cryosphere 2026 report, reviewed and supported by more than 50 leading cryosphere scientists, warned that current levels of warming were “already unsafe” for the Arctic, the Antarctic, mountain glaciers and the polar oceans. It cited Switzerland’s loss of 20% of its glacier ice over the past five years, accelerating sea-level rise threatening hundreds of millions of people worldwide, and increasing water shortages and mountain hazards as glaciers disappear and snow drought conditions spread.

“Although returning to 1.5C will slow ice loss, a truly ‘safe’ temperature target for Earth’s ice is now thought to be closer to 1.0C or even below over the coming centuries,” the report noted. The other report, Overshoot and the Cryosphere: Averting Global Meltdown, drawing on the work of more than 80 polar and mountain scientists, outlined measures to limit the damage caused by temperature overshoot. “These losses can still be limited if overshoot is kept to a minimum by deep emissions reductions followed by scaled-up carbon drawdown,” the report said.

It called for global emissions to be reduced by at least 5% annually, starting immediately, and for net-zero greenhouse gas emissions to be reached by mid-century. “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,” the report further underscored. It said limiting warming could slow the rate of sea-level rise to levels that coastal communities could adapt to, while potentially halting and partially reversing glacier, snowpack and sea ice loss.

“A return to 1.5C and below would initiate some sea ice and glacier re-growth within decades to centuries, and potentially re-establish healthy snowpack levels,” it added. The report further warned that thawing permafrost could release additional carbon into the atmosphere, further intensifying global warming.