A United Nations–backed scientific report has concluded that the Earth’s cryosphere—its glaciers, polar ice sheets and seasonal snow—faces risks of permanent and widespread loss if global temperatures temporarily exceed the 1.5C ceiling set by the Paris agreement.
The assessment warns that the common belief that overshooting the 1.5C target to 2C or 3C could be managed or reversed without long-term consequences is a “persistent myth.” Even short-lived rises above the Paris benchmark, the report says, will expose ice and snow to melting processes that can become irreversible on human timescales.
Permanent losses and policy implications
The authors argue that because some damage to the cryosphere can persist, any period of overshoot must be followed by a swift return to lower temperatures; the report recommends bringing global heating back below 1C after an inevitable period of overshoot. That prescription reflects the finding that delaying rapid emission cuts in favour of relying on later temperature reductions risks committing large parts of the cryosphere to long-term decline.
The report’s findings carry direct implications for coastal communities, freshwater supplies and ecosystems that depend on seasonal snow and glacier melt. By highlighting the potential for lasting ice loss, the assessment frames the pace and scale of mitigation as not only a near-term climate-policy choice but also a determinant of long-term planetary conditions.