Thursday, 22 June 2017

Rapid climate change in Antarctica

Worrying climate news, as a huge ice shelf melts, in Antarctica
  • Rain and significant ice melts in Antarctica surprised scientists
  • In the future, these events could cause ice to melt and break off, which would make sea levels rise

21 June, 2017

(CNN)Antarctica is experiencing weird weather, and the changes have some scientists worried about the future.

There’s an area on the west side of the icy continent called the West Antarctic Ice Sheet, and last January, scientists found a 300,000-square-mile portion of its perimeter was melting. That’s an area roughly two times the size of California, covered in slush.

According to recent research published in Nature Communications, the melt was caused by an unusually strong El Niño event around January 2016.

A melt of this magnitude is relatively rare in Antarctica,” said Julien Nicolas, one of the paper’s authors at the Ohio State University Byrd Polar and Climate Research Center. “There have been about three or four events of this size in the last 40 years.”

For more than two weeks in January 2016, a passive microwave satellite observed surface ice melt two times the size of California.

The news also is ominous for another reason: It means the West Antarctic Ice Sheet is essentially being melted from both sides. El Niños push warm water under the sheet. On top, colder westerly winds usually do enough to stave off any approaching warm weather, but in the 2016 incident, they didn’t.

This event also brought about another surprise for scientists: Rain.

We saw in our observations that there were some rain, we heard from some parties on the Ross Ice Shelf, and we saw it on the weather models,” Nicolas said. “That’s very unusual. We don’t have a record of rain in Antarctica, so we don’t know how often it’s happened in the past.”

Why it matters

Rain and slush would make for a miserable day anywhere, but the weird weather patterns observed over the two-week period in 2016 painted a potentially worrisome picture for the future.

If more extreme El Niños occur, ice shelves such as the Ross Ice Shelf on the West Antarctic Ice Sheet will melt and be weakened. Sometimes, those ice melts can lead to dramatic rivers and waterfalls that leak off of the ice structure. Take a look at a recent video [top of this post] of the Nansen Ice Shelf, which is north of the West Antarctic Ice Sheet

Arctic And Antarctic Sea Ice Is Now Melting At Alarming Rates

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