The effects of global warming in Antarctica may include rising temperatures and increasing snow melt and ice loss. A summary study in 2018 incorporating calculations and data from many other studies estimated that total ice loss was 43 gigatons per year on average during the period from 1992 to 2002 but has accelerated to an average of 220 gigatons per year during the five years from 2012 to 2017.
Video Global warming in Antarctica
Effects
The continent-wide average surface temperature trend of Antarctica is positive and significant at >0.05 °C/decade since 1957. The West Antarctic ice sheet has warmed by more than 0.1 °C/decade in the last 50 years, with most of the warming occurring in winter and spring. This is somewhat offset by cooling in East Antarctica during the fall. This effect is restricted to the 1980s and 1990s.
Research published in 2009 found that overall the continent had become warmer since the 1950s, a finding consistent with the influence of man-made climate change:
- "We can't pin it down, but it certainly is consistent with the influence of greenhouse gases from fossil fuels", said NASA scientist Drew Shindell, another study co-author. Some of the effects also could be natural variability, he said.
2000s
The British Antarctic Survey, which has undertaken the majority of Britain's scientific research in the area, had the following positions in 2006:
- Ice makes cold climate sensitive by introducing a strong positive feedback loop.
- Melting of continental Antarctic ice could contribute to global sea level rise.
- Climate models predict more snowfall than ice melting during the next 50 years, but the models are not good enough for them to be confident about the prediction.
- Antarctica seems to be both warming around the edges and cooling at the center at the same time. Thus it is not possible to say whether it is warming or cooling overall.
- There is no evidence for a decline in overall Antarctic sea ice extent.
- The central and southern parts of the west coast of the Antarctic Peninsula have warmed by about 2.4 °C. The cause is not known.
- Changes have occurred in the upper atmosphere over Antarctica.
The area of strongest cooling appears at the South Pole, and the region of strongest warming lies along the Antarctic Peninsula. A possible explanation is that loss of UV-absorbing ozone may have cooled the stratosphere and strengthened the polar vortex, a pattern of spinning winds around the South Pole. The vortex acts like an atmospheric barrier, preventing warmer, coastal air from moving into the continent's interior. A stronger polar vortex might explain the cooling trend in the interior of Antarctica. [1]
In their latest study (September 20, 2007) NASA researchers have confirmed that Antarctic snow is melting farther inland from the coast over time, melting at higher altitudes than ever and increasingly melting on Antarctica's largest ice shelf.
There is also evidence for widespread glacier retreat around the Antarctic Peninsula.
2010s
Researchers reported December 21, 2012 in Nature Geoscience that from 1958 to 2010, the average temperature at the mile-high Byrd Station rose by 2.4 degrees Celsius, with warming fastest in its winter and spring. The spot which is in the heart of the West Antarctic Ice Sheet is one of the fastest-warming places on Earth.
A study of the Antarctic Peninsula, a small subregion of Lesser Antarctica, published in 2017 found that the temperature trends at the northern tip of the Peninsula, the north-east region of the Peninsula, and the South Shetland Islands "shifted from a warming trend of 0.32 °C/decade during 1979-1997 to a cooling trend of -0.47 °C/decade during 1999-2014" but that this variation was absent from the south-west region of the Peninsula.
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, enough to contribute 7.6 millimeters to sea level rise once all detached icebergs melt. Most ice loss occurred in West Antarctica and the Antarctic Peninsula. The overall loss has substantially accelerated since the 2012 IMBIE assessment: an average loss of 43 gigatons per year during the first ten years, 1992 to 2002, rose to an average of 220 gigatons per year in the last 5 years. East Antarctica appears to have experienced a net gain of a relatively small amount of ice during the 25-year period although uncertainty is greater due to subsidence of the underlying bedrock.
Maps Global warming in Antarctica
References
External links
- White Ocean of Ice Antartica and climate change blog
Source of article : Wikipedia
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