Abstract: White paper on "status of Antarctica and the Southern Ocean Climate System" (SASOCS) has been submitted to Science Committee of Antarctic Research (SCAR) by the Scientific Steering Committee of "Antarctica in Global Climate System"(AGCS). Changes in Antarctic climate system in the past 50 years are assessed and changes for the future 100 years are projected. It is concluded that: 1) large spatial differences were found in the past 50 years in the changes of the Antarctic climate system, rapid warming and glacier retreating occurred over the Antarctic Peninsula and islands in the southern oceans; enhanced warm air masses were detected over the West Antarctica, and winter warming occurred in the mid-troposphere while cooling in the stratosphere. The date of polar vortex decay was delayed. Bottom water in the sector of East Antarctica was purified, and also warmed in some areas such as Weddell Sea. However, there was no obvious changes in surface air temperature and precipitation in the overall Antarctica. Sea ice extent had no obvious changes either in the last 50 years, although large changes were observed in some sectors. 2) It is projected that air temperature over the inland of Antarctica will increase by (3.4±1.0)℃, and sea ice extent will decrease by 30% in the end of the 21st century. Current models are not able to predict the quantitative relations between ice sheet melting and sea level changes under future climate warming scenarios.

Key words: Antarctica, South Ocean, ice sheet, projection, uncertainty