Tuesday, 14 November 2017

Antarctic sea ice plummet - a tipping point

Basicallly, the only signiference of this report is that it is being reported at all. I am getting tired of such articles and expect nothing but half-truths uttered far too late.

'Daunting' Antarctic sea ice plummet could be tipping point

A dramatic drop in the amount of sea ice around Antarctica has scientists wondering if the continent has hit a tipping point. 

Photo credit: NASA Icebridge

14 November, 2017
There has been a record 30 percent decrease in the total amount of sea ice, and this summer it's disappearing from the Ross Sea at a rate not seen in more than 30 years. 
The rapidly changing conditions are having a major impact on this year's scientific research at Scott Base, with scientists describing the changes as "unusual", "unprecedented" and "daunting".
One of the affected scientists is Antarctic oceanographer Dr Natalie Robinson, who studies sea ice and what lies beneath it. 
"We had about 200km of sea ice to play with last year, but this year we're down to about 25-30km, so it's certainly a very different ball game," she told Newshub.
The team's plan to drill holes through the sea ice has proved impossible this season, with some of their sites now just open water.
It's also affected their camping plans. The team usually bring eight modified shipping containers onto the ice to live and work from for several weeks, but Scott Base checked the ice and it was deemed too thin or weak for heavy vehicles to travel on.

The Antarctic sea ice growth in winter and melt in summer is the biggest annual change on the planet. Dr Robinson describes it as the heartbeat or pulse of Earth, and it affects everybody because it drives global weather.
"It basically doubles the size of Antarctica each year and where that sea ice sits determines where the storms go, and when and where they might hit New Zealand," she said. 
But the big changes occurring in Antarctica impact not only weather, but the health of the world's oceans too, delivering oxygen and nutrients.
During November the sea ice edge is usually around 100km further north of where it is this year. For it to have broken out this early is a significant change and it's causing alarms bells to ring.
"This is my 30th trip into the Southern Ocean and Antarctica," climate scientist Professor Gary Wilson told Newshub.
"Of all the visits I've made down here, we haven't seen the sea ice break out as much as it has this early."


Photo credit: Newshub.

This graph shows the normal range of sea ice in November since 1978. In 2016, there was a sudden and dramatic drop.
This year looks to be following suit.
"We're seeing the ice shelves break up around the peninsula, we're seeing sea ice extent change," Prof Wilson said.
"It dropped rapidly last year and we're seeing now early break-up of the sea ice. Many of these things coming together certainly don't bode well."
The sea ice is not only melting ahead of schedule, there's a lot less of it to begin with. Last year there was 30 percent less ice - a drop of around 1 million square kilometres.
Climate scientists believe Antarctica may have hit a tipping point.


Photo credit: Newshub.

"This could be the moment that Antarctica is catching up with the Arctic," Prof Wilson said.
"Geologically we know that's the case that both poles warm equally, but it hasn't been the case yet with the Antarctic. But maybe this is the moment."
There is now less sea ice globally than at any other time since satellite records began in 1978. Last year, when it reached a record low, was also the hottest year on record.
"The impacts that we're having on the planet, it wouldn't surprise me if we are going to some sort of step change in how the Antarctic sea ice system operates," Dr Robinson said.
"We're really in a critical position I think... We're actually in a race because we know changes are coming, and it's just whether we're ahead of the changes to understand them and predict them better."
Prof Wilson said the abrupt change is "exciting" but troubling.
"In one sense it's exciting we're starting to see signs, in another sense it's daunting because when ice melts it tends to melt rapidly," he said.
The scientists and staff at Scott Base have been forced to adapt to the changes in sea ice this season. They can't traverse as far north on it and it needs to be regularly checked for safety when the large vehicles are driving over it.
At least one expedition has had to be cancelled, while cracks have made some regular routes impassable for vehicles carrying scientific equipment.
Climate scientists will be watching closely over the next few years to establish whether this is a one-off event, or the moment Antarctica began to succumb to a rapidly warming planet.
Newshub.




No comments:

Post a Comment