There are currently 25 active volcanoes (denoted by red triangles ),on the Antarctic plate, Mount Erebus has been continuously active since 1972
|The summer sun, acting on the resultant volcanic aerosol gases, causes depletion of the ozone layer, in winter the layer recovers. Misinterpretation (helped by Du Pont who had a new product to sell) of the term ‘aerosol gases‘ lead to the widespread “Ozone Hole” scare of the 1970s.|
Click on Erebus in this list – http://www.volcanodiscovery.com/erupting_volcanoes.html
2013 Satellite views of Erebus http://earthobservatory.nasa.gov/IOTD/view.php?id=87444
Geothermal heating under Marie Byrd Land, plus the Larson B & Ross Ice Shelves has caused some limited melting – https://wattsupwiththat.com/2015/07/10/study-finds-surprisingly-high-geothermal-heating-beneath-west-antarctic-ice-sheet/ & http://archive.reportingclimatescience.com/ & https://news.wustl.edu/news/Pages/Antarctic-seismic-survey.aspx
BTW, CO2 doesn’t cause volcanic eruptions & unlike CO2, volcanoes can also warm water and melt glaciers from below.
Map of the West Antarctic Rift System https://www.ldeo.columbia.edu/~mstuding/tam_map_large.html
Rift basins exist in Ellsworth Land, linking GVIS and the Byrd Subglacial Basin, where elevated heat flow is likely to have influenced ice sheet development and stability. http://nora.nerc.ac.uk/10734/
All the sea ice graphs & links in one handy place for easy reference.