- Antarctic ice is melting about six times faster than in the late 1970s.
- Between 1979 and 2017, melting ice caused global sea levels to rise by about 14 millimeters (0.55 inches).
- The rate at which the ice is melting is also increasing: in 1990 the continent lost 40 billion metric tons (44 billion tons) per year; between 2009 and 2017, that number jumped to 252 billion metric tons (278 tons) annually.
Antarctica is losing ice at a rate that is about six times faster than at the end of the 1970s, and this raised global sea level by about 14 millimeters (0.55 inches) in that period.
These are findings of a study published on January 14 in the journal Annals of the National Academy of Sciences by glaciologist Eric Rignot and his colleagues.
"That's just the tip of the iceberg, so to speak," said Rignot, a professor of earth system science at the University of California, Irvine, in a statement. "As the Antarctic ice sheet continues to melt, we expect Antarctica over the next few centuries to expect an elevation of several meters at sea level."
The team compared snow accumulation on the Antarctic ice sheet with the amount of ice that glaciers dumped in the Antarctic Ocean between 1979 and 2017 using aerial photographs, radar measurements made from space, and Landsat satellite imagery.
The results revealed that the Antarctic ice is melting much faster today than in the past. Approximately in the first decade the researchers analyzed, until 1990, the continent lost 40 billion metric tons (44 billion tons) each year. Between 2009 and 2017, that number jumped to 252 billion metric tons (278 tons) annually.
The team also attempted to connect sea level rise during the study period with melting at different locations. About 6.9 millimeters (0.27 inches) can be traced to Western Antarctica, with 4.4 millimeters (0.17 inches) coming from Eastern Antarctica and 2.5 millimeters (0.098 inches) from the Antarctic Peninsula.
Rignot said the Wilkes Land sector in Eastern Antarctica, which has more ice than West Antarctica and the combined Antarctic Peninsula, has contributed consistently to the rise of the world's oceans since the 1980s. analyze.
"This region is probably more climate sensitive [change] than has traditionally been assumed, "said Rignot, who is also a scientist at the NASA Jet Propulsion Laboratory in Pasadena, Calif.
This climate change strengthens the "western polar winds" -that is, the westbound winds-which, in turn, spread warm, salty water from the depths against the icy edges of the continent.
"As climate warming and ozone depletion send more oceanic heat to these sectors, they will continue to contribute to rising Antarctic sea levels in the coming decades," Rignot said.
Banner image from Adélie penguins in the Antarctic by Jason Auch via Wikimedia Commons (CC BY 2.0).
Rignot, E., Mouginot, J., Scheuchl, B., van den Broeke, M., van Wessem, M. J. and Morlighem, M. (2019). Four decades of mass balance of the Antarctic ice sheet from 1979 to 2017. Annals of the National Academy of Sciences.
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