It is now clearly appearing that deep modifications impact the Earth climate system and that these changes are –at
least in part- linked to anthropogenic activities (IPCC, 2103). As such, there is a widely accepted urgent need for
studying (1) the processes that are involved in these changes (2) their environmental impacts, to accurately predict
future changes and their associated consequences.
Polar regions are amongst the most sensitive to climate change. In the Arctic, average annual temperatures have
increased by 2-3°C since the middle of the last century. In the Antarctic however, impacts of climate change remain
rather contrasted. In the western part of the continent, large impacts are already visible with for example, a
spectacular rise in atmospheric temperatures. This rise contributes to the accelerated melting rated of the local
glaciers, the collapse of ice caps and the dramatic reduction of sea ice cover. Profound impacts on the local
ecosystems have also been reported with important changes in primary productivity and the decline in krill and
Surprisingly, in East Antarctica, little or no changes in temperature are recorded and an increase in the sea ice extent is even observed (Holland & Kwok, 2012). Goosse and collaborators (2009) explain this paradox by the current increase of the Southern Annular Mode index which itself results from an increase of the mean zonal winds. Stronger zonal winds are cooling surface waters and favour the presence of ice around Antarctica. A recent reconstruction of the SAM show that this index has never been as high over the last few centuries (Villalba et al., 2012) and some studies suggests that this situation could result from the combined effects of the ozone depletion and the rise of atmospheric concentrations of greenhouse gases (Thompson & Solomon, 2002; Arblaster & Meehl, 2006).
In the Mertz region, the ice cover has also increased over the last decades (Campagne et al., 2015) and may
explain the decrease in salinity of bottom waters observed since the 1960s in that region (Rintoul, 2007). As such,
although subtler in East Antarctica, it seems that changes occur around the entire continent and that these changes
not only impact local ecosystems but also deeply affect global oceanic circulation.