Arctic Sea Ice More Sensitive to Emissions: Ice-Free Arctic During Last Interglacial Points to Rapid Future Loss

Nature Climate Change, August 10

The Arctic Ocean could be seasonally ice-free at temperatures only slightly above today’s, once land-based Arctic summer temperatures average 4 to 5°C above pre-industrial. This would occur by summer 2035 under high emissions scenarios; parts of the Arctic were already far warmer this summer. These new simulations using CMIP6, by the UK Met Office’s Hadley Centre showed much higher sea ice sensitivity to warming, and moved ice-free September conditions sharply earlier compared to previous modelling.  Hadley’s modelling also resolved a long-standing enigma, showing an ice-free Arctic in the summer months during the last interglacial 130,000 to 116,000 years ago, as a potential analogue for near-term climate change. Their results also demonstrate the significant year-round feedbacks of loss of summer sea-ice on temperatures in the Arctic and northern hemisphere above both land and water. The authors call on policymakers to consider this an urgent challenge motivating more rapid emissions reductions.

Compiled by Amy Imedieke