The first quantitative assessment of the impact of 21st century climate change on ice-free areas of the Antarctic is reported in this week’s Nature. Ice-free areas, covering only one per cent of the continent yet home to all terrestrial biodiversity, have been largely overlooked by researchers, leaving a significant gap in our understanding of climate change impacts on Antarctic species, ecosystems, and their future conservation.
Considerable resources have been directed into studying the consequences of climate change for Antarctic ice sheets and sea levels. By contrast, assessments of the impacts of climate change and associated ice melt on native Antarctic species - including seals, sea birds, arthropods, nematodes, microbes, and vegetation - only started relatively recently.
Jasmine Lee and colleagues found that the Antarctic Peninsula shows the greatest projected future changes in climate. Under the stronger of the two modelled Intergovernmental Panel on Climate Change climate forcing scenarios, ice-free areas could expand by over 17,000 km2 by the end of the century, close to a 25% increase. A projected three-fold increase in ice-free area in the Peninsula could drastically change the availability and connectivity of biodiversity habitats.
It is not known if the potential negative effects will outweigh the benefits for biodiversity; however, expansion of habitats and increasing connectivity in Antarctica might generally be interpreted as a positive change for biodiversity. The authors hypothesize that these changes could eventually lead to increasing regional-scale biotic homogenization, the extinction of less-competitive species and the spread of invasive species. They conclude that if emissions can be reduced and human-caused temperature increases kept to less than 2 °C, then the impacts on ice-free habitat and its dependent biodiversity are likely to be reduced.