Antarctica has lost six times more ice mass per year than 40 years ago, between 1979 and 2017 according to a study published in the journal Proceedings of the National Academy of Sciences . Glaciologists from the University of California at Irvine, NASA’s Jet Propulsion Laboratory (USA) and Utrecht University (Netherlands) also found that accelerated melting has caused global sea levels to rise. more than 1.27 centimeters (half an inch) during that time.
“This is just the tip of the iceberg, so to speak,” says Eric Rignot, leader of the work. “As the Antarctic ice sheet continues to melt, we expect a sea level rise of several meters from Antarctica in the next few centuries.”
The situation is more alarming than we expected
For this study, the researchers conducted the longest assessment of the remaining Antarctic ice pack yet. Thus, for four decades, the project managed to be geographically complete; The research team examined 18 regions spanning 176 basins, as well as the surrounding islands of the Antarctic Peninsula.
Many tools for analysis
The techniques used to estimate the ice sheet balance included a comparison of the accumulation of snowfall in the interior basins due to the discharge of ice by glaciers on their land lines, where the ice begins to float in the ocean and separates from the bed. The data was obtained from very high resolution aerial photographs taken from a distance of about 350 meters through NASA’s Operation IceBridge; satellite radar interferometry from multiple space agencies; and the current series of Landsat satellite images, which began in the early 1970s.
The data
The team was able to discern that between 1979 and 1990, Antarctica shed an average of 40 gigatons of ice mass per year. From 2009 to 2017, about 252 gigatons were lost per year.
The rate of fusion increased dramatically during these four decades. From 1979 to 2001, an average of 48 gigatons per year per decade was established. The rate rose 280% to 134 gigatons for the period 2001 to 2017. Brutal.
The authors explain that one of the key findings of the project is the contribution that East Antarctica has made to the picture of total ice mass loss in recent decades.
“Overall, the Wilkes Land sector in East Antarctica has always been a major participant in the massive loss, even since the 1980s, as our research has shown,” Rignot said. “This region is probably more sensitive to climate change than has traditionally been assumed, and this is important to know, because it contains even more ice than West Antarctica and the Antarctic Peninsula combined.”
The sectors that lose the most ice mass are adjacent to warm ocean water.
“As global warming and ozone depletion send more ocean heat into these sectors, they will continue to contribute to sea level rise from Antarctica for decades to come,” Rignot concluded.
The bottom line is that Antarctica is losing a lot of ice and that there are vulnerable areas in east and west Antarctica , with little sign of slowing down as the oceans warm.
Referencia: Eric Rignot el al., “Four decades of Antarctic Ice Sheet mass balance from 1979–2017,” PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1812883116
