Melting Antarctic Glaciers Triples and Drives Sea Level Rise
Continent has lost 3 trillion tons of ice in the last 25 years, contributing to an average rise of 7.6 millimeters in sea level - 40% of them in the last five years alone.
Image: Ian Joughin, University of Washington
Antarctica lost 3 trillion tons of ice between 1992 and 2017, causing sea levels to rise by 7.6 millimeters. The great concern, however, is due to the fact that most of this increase has taken place in the last five years, as a result of global warming. This is what a study released on Wednesday (13) in the journal Nature reveals.
The data are the result of the most complete study ever made on the changes suffered by the Antarctic ice sheet. 84 scientists from 44 organizations participated in the survey, for which data from 24 independent satellites were analyzed. The work is an important warning to the fact that the effects of climate change are already being felt - and could represent great losses for the future.
The melting recorded so far represents a tiny portion of the total ice present on the continent. If it melted completely, the ice stored there could raise sea level by 58 meters.
Led by Andrew Shepherd of the University of Leeds and Erik Ivins of NASA, the research reveals that until 2012 the continent's ice loss was stable, at a rate of 76 billion tonnes per year, contributing to a rise in the level of the average sea of 0.2 mm per year. From 2012 to 2017, that pace tripled, jumping to a loss of 219 billion tonnes per year – 0.6 mm per year of sea level rise.
“According to our analysis, there has been a jump in Antarctica's ice loss over the past decade and the continent is causing sea levels to rise faster today than at any time in the last 25 years. This has to be a matter of concern for governments we trust to protect coastal cities and communities,” Shepherd said in a press release.
Analyzing satellite images, it was possible to track how and where the main losses and gains are occurring, and to make a net balance of the continent's ice mass.
The region that has felt the most from ocean melting is West Antarctica, which has seen ice loss go from 53 billion tons to 159 billion tons per year. An animation made by the researchers (see below) shows that the thickness of the ice shelf at the site has been thinning by up to 30 meters. Most of this took place on Pine Island and the Thwaites Glaciers.The Antarctic Peninsula's rate of ice loss has risen from about 7 billion to 33 billion tons per year as a result of the collapse of the ice shelf. East Antarctica, for the time being, the mass balance remains uncertain and is indistinguishable from zero.
