Rain once a rare occurrence on the frozen expanse of Antarctica, is becoming more frequent particularly along the Antarctic Peninsula and scientists warn it could fundamentally reshape the region’s glaciers, ecosystems and research infrastructure.
According to new research led by Bethan Davies of Newcastle University, the peninsula already the fastest-warming part of the continent is likely to see more precipitation falling as rain rather than snow this century under all greenhouse gas emission scenarios.
The findings suggest that as temperatures increasingly rise above 0°C, rainfall will accelerate surface melt, destabilise ice shelves and place growing stress on wildlife.
Extreme events are already offering a preview of what lies ahead. In February 2020, temperatures on the northern peninsula soared to 18.6°C during an unprecedented heatwave, triggering record ice shelf melt. More recently, atmospheric rivers long bands of warm, moisture-laden air have brought winter rainfall and above-freezing temperatures to the region.
Rain falling on snow and ice carries heat, speeding up melting. On glaciers, meltwater can seep to the base, lubricating the ice and increasing its flow into the ocean. On floating ice shelves, rain compacts snow and forms surface ponds that absorb more solar energy. These ponds can fracture ice from above, a process linked to the collapse of the Larsen A Ice Shelf and Larsen B Ice Shelf in the early 2000s.
Sea ice is also vulnerable. Reduced snow cover lowers reflectivity, causing faster melt and diminishing natural barriers that buffer ocean waves. This, in turn, increases iceberg calving and glacier retreat.
The ecological consequences could be profound. Penguin chicks, adapted to dry, frigid conditions, are particularly vulnerable. Heavy rain can soak their non-waterproof down feathers, leading to hypothermia and increased mortality.
Ice-dependent species such as Adélie and chinstrap penguins may face mounting pressure as sea ice declines and krill populations fluctuate. Meanwhile, more adaptable gentoo penguins are expanding southward, potentially altering the peninsula’s ecological balance.
Rainfall also disrupts microscopic snow algae that form the base of Antarctic terrestrial ecosystems. These organisms darken the snow surface, influencing melt rates, and support microbial life. With snow cover thinning, the ground beneath faces sharper temperature swings and ecological stress.
Beyond ecosystems, human infrastructure is increasingly exposed. Airstrips and research stations were built for snow, not sustained rainfall. Freezing rain can render runways unusable, while slush and meltwater damage equipment and buildings.
Historic sites are also at risk. The peninsula hosts numerous protected huts and relics from early exploration. Thawing permafrost and heavier rainfall threaten their structural integrity, accelerating timber decay and foundation instability.
Scientists describe the Antarctic Peninsula as an early indicator for broader coastal Antarctica, including the vulnerable West Antarctic Ice Sheet. If global temperatures rise toward 2°C or 3°C this century, rainfall and extreme melt events are expected to intensify.
While limiting warming to 1.5°C may not halt these changes entirely, researchers say it could significantly slow the pace at which rainfall transforms one of Earth’s most fragile environments.
Rain in Antarctica, once an anomaly, is becoming a defining feature of a warming world with consequences that may extend far beyond the continent’s icy shores.