Antarctica's worst-case climate scenario projects major sea-ice loss

A modelling study focused on the Antarctic Peninsula finds that under a very high emissions pathway regional temperatures could reach about 4.4°C above pre-industrial levels by 2100, with sea ice around the Peninsula falling by roughly 20% and the Peninsula contributing about 22 millimetres to global sea level by 2100.

Scientists modelled how the Antarctic Peninsula might change under low, medium-high and very high emissions scenarios. The peninsula is well observed and is especially sensitive to human-caused warming. Under the very high emissions case the study projects about 4.4°C of regional warming by 2100 and notably reduced sea-ice coverage. The authors note that changes in Antarctica can propagate through sea level and oceanic and atmospheric circulation. Key findings: - Under the very high emissions scenario, sea ice around the Antarctic Peninsula is projected to decline by about 20% by 2100. - The Antarctic Peninsula alone could add roughly 22 millimetres to global sea level by 2100 and about 172 millimetres by 2300 in the hotter scenario reported by the study. - The researchers used three warming pathways (low ≈1.8°C, medium-high ≈3.6°C, very high ≈4.4°C above pre-industrial) and emphasise that Antarctic changes affect global sea level and ocean–atmosphere links. Summary: The study describes outcomes ranging from modest regional change under the low pathway to substantial sea-ice loss and additional sea-level contribution under the very high pathway. Undetermined at this time.