The warning signs are already visible. Increased rainfall on the Antarctic Peninsula threatens glaciers, ecosystems, infrastructure and irreplaceable heritage.
Antarctica was for millennia a place of cold and silencea continent defined by ice, wind and blinding light. The scientists who work there carry padded coats, snow goggles and sunscreen — not umbrellas.
Os planes land on dry runways of gravel. The historic cabins remain well-preserved in air so dry it serves as a natural archive. In this world, the rain was little more than a detail.
But the rain is now fall with increasing frequency on the Antarctic Peninsula, the narrow, mountainous arm of the continent that stretches north toward South America, warns Bethan Daviesprofessor of glaciology at the University of Newcastle, in an article in .
This is the hottest area in Antarcticaand is warming faster than the rest of the continent — and much faster than the global average. Scientists now see this region as a preview of what much of the Antarctic coast could face in the coming decades.
A team of researchers led by Davies recently modeled the evolution of the peninsula in three emissions scenarios — high, intermediate and low — by the end of this century.
The conclusions of the , published last week in Frontiers in Environmental Scienceare clear: as temperatures riseprecipitation will increase slightly overall, but the decisive change It’s in your shape.
Rain, not snow, will represent a growing share of what falls from the sky. And as days above 0°C become more common, this precipitation will profoundly reshape the region.
The warning signs are already visible. In February 2020, a heat wave caused temperatures to rise to 18.6°C in the north of the peninsula, in a place where these values were practically unthinkable. Nearby, the surface of ice shelves melted at a record rate.
Atmospheric riverslong corridors of warm, moist air originating from lower latitudes, are becoming more frequent and more intense.
In February 2022, one of these phenomena triggered a thaw record surface area across the entire peninsula. In July 2023, another brought rain and temperatures of +2.7°C in the middle of the Antarctic winter, to areas where neither had been recorded before.
The relationship between rain and snow is destructive. On the Antarctic Peninsula, rain strips glaciers of the snow that feeds them, while meltwater that seeps down to the base of the glaciers lubricates the ice, causing them to speed toward the ocean. The result is an increase in the calving of icebergs and a faster loss of ice mass overall.
On floating ice shelves, rain compacts snow to the surface and creates meltwater ponds. As this accumulated water absorbs more solar radiation than reflective snow, heats up quickly and can melt at depth across the shelf into the ocean below, weakening the structure from within.
This process was directly involved in the catastrophic collapse of ice shelves Larsen A e Bin the early 2000s — events that still mark the scientific community today.
Sea ice faces pressures of its own. Reducing snow cover accelerates melting, and its loss eliminates natural barriers that protect glacier fronts from wave churn and provide essential habitat for seaweed, krill, penguins and seals.
As ecological consequences are already underway. You penguinswhich evolved in a polar desert, are not adapted to rain. The chicks’ down is not waterproof, and intense rain can cause hypothermia and death. Flooding of nests further exacerbates the threat.
Coupled with warming oceans and declining krill populations, the pressure on emblematic species such as Adélie penguins and chinstrap penguins is increasing. Gentoo penguins, more adaptable, are expanding south, displacing their ice-dependent “cousins”.
The precipitation also disturbs snow algae — microscopic organisms that sustain Antarctic terrestrial ecosystems and feed microbes and invertebrates.
When the rain removes the snow cover, exposes the soil to more severe and more variable conditions. At the same time, warming water can open the door to invasive marine speciess, such as crabs and mussels.
A human presence on the peninsula is also at risk. The research stations were designed for snow, not persistent rain. Rain that freezes on tracks makes them unusable. Mud and meltwater damage buildings, instruments and equipment. Some locations may even have to be completely relocated.
Os 92 officially designated historic sites in Antarctica — wooden huts, equipment warehouses, and early scientific facilities, many of them on the peninsula — andface a particularly uncertain future.
Thawing permafrost and increased rainfall threaten its structural integrityaccelerating the degradation of wood and destabilizing foundations in one of the most difficult places in the world, from a logistical point of view, to carry out conservation work.
A Antarctic Peninsula is already being transformed. If global temperatures reach 2°C or 3°C above pre-industrial levels over the course of this century, the pace of change will accelerate markedly. Damage to glaciers, ecosystems, infrastructure and irreplaceable heritage can become serious and, in many cases, irreversible.
Limit heating to 1.5°C will not completely stop these changes. But it will be able to determine whether the transformation of Antarctica happens over the course of generations — or yearsconcludes Davies.
