A team led by a Portuguese researcher recently studied the ground surface temperatures in Barton Peninsula (Antarctic Peninsula), where ice-free areas are scattered among rocky hills and snow patches. They installed 20 small temperature sensors called iButtons at different elevations, slopes, and near snow patches, recording ground temperatures every three hours for a full year. By analyzing this data, the team could uncover what controls the freezing and thawing of the ground.

So, what did they discover? Elevation turned out to be the main factor: the higher you go, the colder the ground gets, with mean annual temperatures dropping from just above freezing at low elevations to below -2°C at higher sites. Snow cover also plays a huge role, acting like a natural blanket: areas with longer-lasting snow had longer freezing seasons and slower warming. Even the shape of the land and how much sunlight hits it influenced the temperature.

The team identified seven daily ground temperature regimes: some frozen all day, some thawed, and some cycling between freezing and thawing. By combining this information, they classified the whole area into four main types of annual temperature regimes, ranging from long frost seasons near snow patches to short frost seasons with rapid warming at lower elevations. They even created a model that can map these patterns across the Peninsula with 90% accuracy.

Why does this matter? These findings show just how sensitive ground temperatures are to small changes in topography and snow cover. This matters not only for understanding permafrost and climate in Antarctica but also for predicting how these areas might respond to future warming. In other words, even tiny details in the landscape can have a huge impact on the frozen world beneath our feet!

Source: Baptista, J., Vieira, G., & Lee, H. (2024). Ground surface temperature regimes are controlled by the topography and snow cover in the ice-free areas of Maritime Antarctica. Catena, 240, 107947

However, since 1950, the Antarctic Peninsula has experienced a steady increase in air temperatures, which is already having a noticeable impact on permafrost dynamics.

In a new study led by a Portuguese researcher, scientists modelled the evolution of permafrost temperature and active layer thickness on King George Island, located in the Antarctic Peninsula. The aim was to understand how these variables have changed over time and to develop a methodology that could later be applied to other ice-free regions of the peninsula.

To achieve this, the team used the CryoGrid Community Model, fed with borehole data from the King Sejong Station (which provides ground temperature records at various depths) and ERA5 climate reanalysis data.

The results are clear: since 1950, permafrost temperatures have increased by about 2 °C, and the active layer has thickened from 1.6 to 3.5 metres. And the most concerning part? This warming has accelerated significantly since 2016.

But why is this important? Because permafrost degradation in Antarctica affects hydrological dynamics, controls the flow of sediments and contaminants, causes ground instability, and influences vegetation development — all of which have direct impacts on terrestrial ecosystems and biodiversity.

This study represents an important step toward a better understanding of how climate change is affecting Antarctica, and it helps us anticipate what might happen in the future to the planet’s frozen ground.

Source: Baptista, J. P., Vieira, G. B. G. T., Lee, H., Correia, A. M. D. C. S., & Westermann, S. (2025). Modelling the evolution of permafrost temperatures and active layer thickness in King George Island, Antarctica, since 1950. Frozen ground/Antarctic. https://doi.org/10.5194/egusphere-2025-150

Author: Diana Martins

A recent study by European researchers investigated the relationships between ice melt in West Antarctica and atmospheric rivers. These atmospheric events consist in narrow and elongated bands associated with elevated transport of water vapor that travel from tropical regions to high latitudes. When the jet stream becomes wavier, the extratropical cyclones around Antarctica transport the atmospheric rivers toward the continent. These events bring heat and humidity and, when they reach land, they can affect the surface of Antarctica.

Using an algorithm to detect atmospheric rivers developed for Antarctica in synergy with observations of ice melt, this study produced a climatology of ice melt events related with atmospheric rivers from 1979 to 2017. To analyze the distribution of events and the associated impacts, Antarctica was divided in four quadrants. The focus of this study were the two quadrants that cover the West Antarctic region – West Antarctic Ice Sheet (WAIS) and Antarctic Peninsula and Weddell Sea (AP-Weddell).

The results showed that atmospheric rivers are associated with increased probability of ice melt events. Although atmospheric rivers are rare events in West Antarctica (around 12 per year), these are associated with approximately 40 % of ice melt in Ross Ice Shelf up to 100 % in higher regions of Marie Byrd Land in the summer, and 40 to 80 % of ice melt on the Wilkins, Bach, George VI and Larsen B and C ice shelves in the winter.

The largest ice melt events in WAIS occur only a few times per decade. Yet, the warming and continuous increased activity of atmospheric rivers can increase the frequency of ice melt events with consequences for the stability of Antarctic ice shelves.

———–

Source: Wille, J. D., Favier, V., Dufour, A., Gorodetskaya, I. V, Turner, J., Agosta, C. and Codron, F. 2019, West Antarctic surface melt trigered by atmospheric rivers, Nature Geosciences, 12, 911–916, DOI: 10.1038/s41561-019-0460-1

Author: Carolina Viceto