regularly during certain months of the year. At greater warming levels, the effect is likely to disappear because of increasing concentrations of water vapor over Antarctica. Antarctica's dryness means the air contains little water vapor and conducts heat poorly. There were fewer than twenty permanent
weather stations across the continent and only two in the continent's interior.
Automatic weather stations were deployed relatively late, and their observational record was brief for much of the 20th century
satellite temperature measurements began in 1981 and are typically limited to cloud-free conditions. Thus, datasets representing the entire continent had begun to appear only by the very end of the 20th century. The exception was the
Antarctic Peninsula, where warming was pronounced and well-documented; it was eventually found to have warmed by since the mid 20th century. In particular, a 2002 analysis led by
Peter Doran indicated stronger cooling than warming over Antarctica between 1966 and 2000, and found the
McMurdo Dry Valleys in East Antarctica had experienced cooling of 0.7 °C per decade. wrote the novel
State of Fear. The novel featured a fictional conspiracy among climate scientists to fake evidence of global warming, and cited Doran's study as proof that there was no warming in Antarctica outside of the Peninsula. That novel was mentioned in a 2006
US Senate hearing in support of
climate change denial, and Peter Doran published a statement in
The New York Times decrying the misinterpretation of his work. By 2009, researchers had combined historical weather-station data with satellite measurements to create consistent temperature records going back to 1957 that demonstrated warming of >0.05 °C per decade across the continent, with cooling in East Antarctica offset by the average temperature increase of at least 0.176 ± 0.06 °C per decade in West Antarctica. That paper was widely reported on, and subsequent research confirmed clear warming over West Antarctica in the 20th century, the only uncertainty being the magnitude. During 2012–2013, estimates based on WAIS Divide
ice cores and revised temperature records from
Byrd Station suggested a much-larger West-Antarctica warming of since 1958, or around per decade, but some scientists continued to emphasize uncertainty. In 2022, a study narrowed the warming of the Central area of the
West Antarctic Ice Sheet between 1959 and 2000 to per decade, and conclusively attributed it to increases in greenhouse gas concentrations caused by human activity. Likewise, the strong cooling at McMurdo Dry Valleys was confirmed to be a local trend. warmed by 0.61 ± 0.34 °C per decade between 1990 and 2020, which is three times the global average. On the other hand, changes in atmospheric circulation patterns like the
Interdecadal Pacific Oscillation (IPO) and the
Southern Annular Mode (SAM) slowed or partially reversed the warming of West Antarctica, with the Antarctic Peninsula experiencing cooling from 2002. While a variability in those patterns is natural, past
ozone depletion had also led the SAM to be stronger than it had been in the past 600 years of observations. Starting around 2002, studies predicted a reversal in the SAM once the ozone layer began to recover following the
Montreal Protocol, and those changes are consistent with their predictions. Under the most intense
climate change scenario, known as
RCP8.5, models predict Antarctic surface temperatures to rise by by 2070 and by on average by 2100, which will be accompanied by a 30% increase in precipitation and a 30% decrease in sea ice by 2100. The Southern Ocean waters "south of
50° S latitude would also warm by about by 2070. than the more-moderate scenarios like RCP 4.5, which lie in between the worst-case scenario and the
Paris Agreement goals. If a low-emission scenario mostly consistent with the Paris Agreement goals is followed, then Antarctica would experience surface and ocean warming of less than by 2070, while less than 15% of sea ice would be lost and precipitation would increase by less than 10%. However, it would take up a smaller
fraction of heat (right) and emissions per every additional degree of warming when compared to now. Between 1971 and 2018, over 90% of
thermal energy from
global heating entered the oceans. The Southern Ocean absorbs the most heat; after 2005, it accounted for between 67% and 98% of all heat entering the oceans. It is also a highly important
carbon sink. Those properties are connected to the
Southern Ocean overturning circulation (SOOC), one half of the global
thermohaline circulation. As such, estimates on when global warming will reach – inevitable in all scenarios where greenhouse gas emissions have not been significantly lowered – depend on the strength of the circulation more than any factor other than the overall emissions. Since the 1970s, the upper cell has strengthened by 50–60%, and the lower cell has weakened by 10–20%. by shifting the
Southern Annular Mode (SAM) pattern, which alters winds and precipitation. Fresh
meltwater from the erosion of the West Antarctic ice sheet dilutes the more-saline Antarctic bottom water, which flows at a rate of 1100–1500 billion tons (GT) per year. Greater melting and further decline of the circulation is expected in the future. One study says the strength of the circulation would halve by 2050 under the worst climate-change scenario, with greater losses occurring afterwards.
Paleoclimate evidence shows the entire circulation has significantly weakened or completely collapsed in the past; preliminary research says such a collapse may become likely once global warming reaches between and . However, that estimate is much less certain than for the majority of
tipping points in the climate system. Such a collapse would be prolonged; one estimate places it sometime before 2300, rather than in this century. As with the better-studied
Atlantic meridional overturning circulation (AMOC), a major slowing or collapse of the SOOC would have substantial regional and global effects. Regional effects vary: northern Africa experiences increasing water scarcity, East Africa shows highly variable rainfall with alternating drought and heavy rain, and southern Africa faces rising temperatures, erratic flooding, and extended droughts. Scientific programs, including South Africa's
South African National Antarctic Programme, monitor Antarctic climate processes and their downstream impacts, supporting regional climate adaptation strategies. ==Effects on the cryosphere==