...
Based on a number of temperature reading methods, including permanent floats that decrease in depth to measure temperature at a range of depths, and ship measurements, Gille found that, since 1950, there has been an average increase in temperature of about 0.1° C from 1955 to 1995 in the Southern Ocean. Most of this warming is in the upper km of the ocean. These readings were taken here, however, are a measure of primarily subsurface temperature readings due to the Antarctic Circulation Current's presence in the region, which brings mid-depth water to the surface. However, from 1930 to 1955, there was a negligible increase in temperate of the same region, suggesting that this rise has not been long-term. Also, the increase in temperature of the southern ocean is not uniform; the greatest increase in temperature was found to be at the more southern latitudes, but also is significant in discrete areas along the southern coast of Africa. This figure nicely illustrates the discovered temperature changes, in °C/year.\
\
It is also of note that most temperature changes were found along a subset of ocean called "Subantarctic mode water," which annually ventilates and is therefore more sensitized to climate changes.
...