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= Climate change in Antarctica =

Temperature change in Antarctica is not stable over the whole continent. West Antarctica is warming rapidly, while the inland regions are cooled by the winds in Antarctica. Water in the West Antarctica has warmed by 1°C since year 1955. Further increase in temperature in water and on land will affect the climate, ice mass and life on the continent. Today's greenhouse gas concentrations are higher than ever according to ice cores from Antarctica which indicates that warming on this continent is not part of a natural cycle. Antarctica has lost 2720 ± 1390 gigatons of ice during the period from 1992 to 2017, and estimations are that in year 2100 the sea level will rise by 25 cm just from the water bound in ice in Antarctica. This will affect currents both in Antarctica and neighboring oceans. Climate change affects the biodiversity on the continent but it's hard to know the extent of it because many species in Antarctica are still not discovered. There are documented changes to flora and fauna on the continent already. Changes include increase in population size in plants and adaptation to new habitat by penguins. Increase in temperature lead to melting of permafrost which contributes to release of greenhouse gases and also chemicals that are trapped in the ice today. Even with goals and limitations made by the Paris Agreement it might be too late to reverse ice melting in West Antarctica, and future changes in climate in Antarctica will affect all parts of the globe.

Temperature and weather changes
Temperatures measured after year 1957 until early 2000's show a difference in trend on the Antarctic Peninsula and the continental interior. According to a study in 2009, West Antarctica increased in temperature by 0.176 ± 0.06 °C per decade between year 1957 and 2006. Another study in year 2020 show a cooling of the air temperature by 0.7°C per decade from year 1986 to 2006 at Lake Hoare station. Both studies indicate that change in temperature may alter the wind pattern, and according to another study in year 2020 the westerlies winds around the South Pole have got more intense in the last half of the twentieth century. Same study indicates that the Antarctic Peninsula was the fastest-warming place on Earth, closely followed by West Antarctica, but these trends weakened in the early 21st-century. Conversely, the South Pole in East Antarctica barely warmed last century, but in the last three decades the temperature increase there has been more than three times greater than the global average, warming by 0.61 ± 0.34 °C per decade. In February 2020, the continent recorded its highest temperature of 18.3 °C, which was a degree higher than the previous record of 17.5 °C in March 2015. Models predict that Antarctic temperatures will be up 4 °C, on average, by 2100 and this will be accompanied by a 30% increase in precipitation and a 30% decrease in total sea ice. A main component of climate variability in Antarctica is the Southern Annular Mode, which showed strengthened winds around Antarctica in summer of the later decades of the 20th century, associated with cooler temperatures over the continent. The trend was at a scale unprecedented over the last 600 years; the most dominant driver of this mode of variability is likely the depletion of ozone above the continent.

The temperature in the upper layer of the ocean in West Antarctica has warmed 1 °C since 1955. Antarctic Circumpolar Current(ACC) is warming faster than the whole global ocean. Changes to this current will not only affect Antarctica's climate but also water flow in Atlantic, Pacific and Indian ocean.

There are natural fluctuations in climate, and by studying ice cores in Antarctica it's shown that these fluctuations are correlated to green house concentration in the atmosphere. The fluctuations are referred to glacial and interglacial periods. The concentration of carbon dioxide during glacial periods is 180 parts per million and methane 300 parts per million. During the interglacial periods the concentration is 320 parts per million for carbon dioxide and 790 parts per billion for methane. Today the concentration is 417 parts per million for carbon dioxide (April 2022) and 1,896 parts per billion for methane (April 2022), showing that concentrations today are not withing normal fluctuations.

Changes in ice mass
A 2018 systematic review of all previous studies and data by the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) found that Antarctica lost 2720 ± 1390 gigatons of ice during the period from 1992 to 2017 with an average rate of 109 ± 56 Gt per year, enough to contribute 7.6 millimeters to sea level rise once all detached icebergs melt. Most ice losses occurred in West Antarctica and the Antarctic Peninsula. The study estimates an increase in ice-sheet mass loss from 53 ± 29 Gt per year to 159 ± 26 Gt per year from 1992 to the final five years of the study in the West Antarctica. On the Antarctic Peninsula average loss of ice-sheet mass is estimated to −20 ± 15 Gt per year with an increase in loss of roughly 15 Gt per year after year 2000. In both regions the loss was affected by diminution in ice thickness and floating ice shelves. The results from East Antarctica show uncertainty but estimates an average in loss of 5 ± 46 Gt ice per year during the period of the study.

Through his ongoing study, climate scientist, Nicholas Golledge, has estimated that Antarctic ice sheets will continue to melt and will have a profound effect on global climate. According to Golledge's analysis, by the year 2100, 25 centimeters of water will have been added to the world's ocean, as water temperature continues to rise. Ice melt in the future will differ depending on average rise in global temperature caused by greenhouse gas emissions. Conclusion on Paris Climate Agreement policies is that if global warming is limited to no more than 2 °C Celcius increase, the loss of ice in Antarctica will continue at a current rate until the end of the century. Although, current policies allow warming of 3 °C Celcius leading to a fast acceleration in ice loss after 2060 contributing to a global mean sea level rise of 0.5 cm per year by 2100. Scenarios that include even higher emissions will have bigger devastating effects on global mean sea level rise.

The Antarctic ice sheet accounts for 90% of the world’s ice volume and 70% of all freshwater on Earth. Global warming has resulted in rapid mass loss of the Antarctica ice sheet. A study published in 2022, revealed that glacier melting from the Antarctica ice sheet accounted for most of the total freshening occurring in the Southern Ocean. The freshening of the Southern Ocean results in increased stratification and stabilization of the ocean. This would weaken overturning circulation and prevent saltier deep water from rising to the surface waters.

Black carbon and effects on albedo
Black carbon accumulated on snow and ice reduces the reflection of ice causing it to absorb more energy and accelerate melting. This can create an ice-albedo feedback loop where meltwater itself effects the acceleration of melting because of the affected surface reflection. In Antarctica black carbon has been found on Antarctic Peninsula and around Union Glacier with the highest concentrations near anthropic activities. The result of human activities in Antarctica will accelerate snowmelt on the continent, but the speed of melting will differ depending on how far black carbon and other emissions will spread, along with the size of the area that they will cover. A study from 2022 estimate that the seasonal melt during the summer period will start sooner on sites with black carbon because of the reduction in albedo reflection that ranges from 5 to 23 kg/m2.

Impacts on biodiversity
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