Jan 14, 2019

Antarctica is losing ice 6 times faster than in 1980s

The western edge of iceberg A68, as seen in 2017. Photo: NASA/Nathan Kurtz

Antarctica is shedding ice at an increasingly rapid rate, potentially imperiling coastlines around the world as sea levels increase in response, a new study finds.

Why it matters: Antarctica is already contributing a growing amount to sea level rise, the study found, and things could get much worse.

The big picture: The new study, published Monday in Proceedings of the National Academy of Sciences, found that Antarctica has shed ice at a growing rate in recent decades.

  • From 1979 to 1990, the average annual ice mass loss rate was 40 billion metric tons per year.
  • This jumped to 252 billion metric tons per year, between 2009 to 2017.

The study, from glaciologists at the University of California at Irvine and Netherlands' Utrecht University, also contains the worrisome conclusion that East Antarctica has been losing mass since the 1980s. That's important because previous studies had regarded that part of the continent as stable or not yet undergoing a net loss.

Details: Warming ocean waters are weakening floating ice shelves, which act like doorstops that keep massive amounts of inland ice from flowing quickly into the sea.

  • The warm waters, pumped in by natural variability and human-caused climate change, are melting such shelves from below, and the new study found the parts of Antarctica that are melting the fastest are ones that have an ocean influence.

The researchers set out to complete a comprehensive survey of the ice-bound continent using a variety of data sources, such as NASA aircraft reconnaissance and satellite measurements. They examined 18 regions that included 176 glacier basins.

  • The study took into account the balance between inland snowfall and coastal ice melt. As recently as 2001, scientists thought that increased snowfall could compensate for ice loss at the margins, but that is no longer the case.

What they're saying: "The really big questions are whether the recent acceleration in mass loss will continue, leading to rapid deglaciation of one or more basins and much faster sea-level rise," Richard Alley, a geosciences professor at Penn State University, told Axios via email. Alley was not involved in the new study.

  • "We do not know the answer to this, but we do know that the more humans warm the climate, the more likely it is that the ice will respond."
  • Robin Bell, who studies ice sheets at Columbia's Lamont-Doherty Earth Observatory, says the new study is a welcome addition to the literature on Antarctica. "[It] Shows how the ice sheets are in a different place and changing faster than we could have imagined in the 1970's," she said in an email to Axios.

What's next: Glaciologists need to reconcile the new study's findings with a large study published last year that found East Antarctica has not been losing ice so quickly, though it raised the possibility of future losses.

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World coronavirus updates

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There are no COVID-19 patients in hospital in New Zealand, which reported just 21 active cases after days of zero new infections. A top NZ health official said Tuesday he's "confident we have broken the chain of domestic transmission."

By the numbers: Almost 5.5 million people have tested positive for the novel coronavirus as of Tuesday, and more than 2.2 million have recovered. The U.S. has reported the most cases in the world (over 1.6 million from 14.9 million tests).

U.S. coronavirus updates

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Andrew Witherspoon/Axios. This graphic includes "probable deaths" that New York City began reporting on April 14.

Coronavirus antibody tests are still relatively unreliable, and it's unclear if people who get the virus are immune to getting it again, the Centers for Disease Control and Prevention cautioned on Tuesday.

By the numbers: More than 98,900 people have died from COVID-19 and over 1.6 million have tested positive in the U.S. Over 384,900 Americans have recovered and more than 14.9 million tests have been conducted.

Coronavirus dashboard

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  1. Global: Total confirmed cases as of 9:30 p.m. ET: 5,588,299 — Total deaths: 350,417 — Total recoveries — 2,286,827Map.
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Updated 1 hour ago - Politics & Policy