Ice floating in the sea

The future of the Antarctic Peninsula

 

A briefing note published today by the Grantham Institute looks at the expected impacts of 1.5°C of global warming above pre-industrial levels on the Antarctic Peninsula, and includes work from PML ecologist, Dr Angus Atkinson.

The Antarctic Peninsula has warmed by more than 2.5°C in the last century, more than anywhere else in the Southern Hemisphere. The northern Peninsula now sees 25-80 days per year over 0°C.

This briefing note lays out a series of predictions for the Peninsula in the event of 1.5°C of global warming, with temperature increases, particularly during winter and higher levels of rain, snow and ice melt, causing surface run-off and altering ground strength. It is also expected that the surrounding ocean will become more turbulent.

Marine ecosystems in the region, already impacted by over-exploitation through sealing, whaling and fishing over the last two centuries, could be affected by warming with changes in organism behaviour, physiology and location. Additionally, southward shifts in marine life distribution have been observed and will continue in a 1.5°C warming scenario.

Co-author Dr Atkinson said: "Polar marine ecosystems are particularly sensitive to climatic warming because the fauna have evolved to function at low and relatively stable temperatures - even modest increases can have major consequences.

Other predicted impacts reported in the briefing point to highly variable sea ice extent to the west of the Antarctic Peninsula and an accelerated retreat of the marine glacier margins, with more iceberg production. Ice shelves will produce more meltwater, but there are unlikely to be further collapses like those of Larsen A in 1995 and Larsen B in 2007.

On land, ice-free areas will continue to expand, providing habitats for plants and invertebrates, which will likely benefit from the increased temperatures. The prevalence of non-native species, surviving in the Antarctic under warmer conditions, is likely to be a much greater threat to native biodiversity than the direct effects of warming.

The briefing concludes that the ice shelves are likely to be maintained and indicates that marine life can still be protected under the 1.5°C warming scenario. However, if temperatures continue to rise, the change to the Antarctic Peninsula will be "irreversible and dramatic".

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