Sensitivity and responses to climate change in the Subantarctic periglacial environment

The Subantarctic islands constitute a distinct periglacial environment of low mean annual and diurnal temperature range. Ground thermal monitoring on Marion Island demonstrates how the low radiation inputs and high moisture conditions result in near-isothermal soil temperature conditions. This paper describes and analyses this distinctive soil temperature regime and demonstrates a high sensitivity of the Subantarctic frost environment to climate change. The latter is expressed by a rapid transition from high-frequency shallow diurnal frost activity to deep seasonal freezing and permafrost. The results from this analysis are applied to the palaeoenvironmental interpretation of relict, early Holocene periglacial landforms representing colder climates, as well as to current landscape responses due to climate warming on Marion Island.