Amplification of climate change in the Arctic

In contrast to multi-year old ice, first-year old ice—ice that formed only since the last melt season—is thinner, saltier, and much more prone to melt.

Over the years, the loss of sea ice has become especially manifest in the older ice, as illustrated by the image below.

Salt content and hardness play a part in multi-year ice’s resistance to melt, explains a recent NOAA article, but the main characteristic that allows the ice to survive the melt season is thickness.

Screenshots from: PIOMAS Arctic Sea Ice Thickness Simulation 1978-2011

The decline in thickness over the years goes a long way to explain the self-reinforcing character of sea ice decline in the Arctic.

As another recent NOAA article describes, there is “something extra” behind the record ice retreats of the past 6 years: each June, the prevailing winds shifted from their normal west-to-east direction and instead blew strongly from the south across the Bering and Chuchki Seas (left on the image below), over the North Pole, and out toward Fram Strait. (The length of the lines is qualitative: longer lines mean stronger winds.)

Average June wind vectors in 2007-2012 (orange) compared to 1981-2010 average (white) based on NCEP reanalysis data provided by Physical Sciences Division at NOAA ESRL. Map by Dan Pisut, NOAA Environmental Visualization Lab.

The image below shows the unusual air pressure patterns that gave rise to the wind shift. Air pressure across the Arctic in Junes from 2007-2012 was completely lopsided, with two pockets of higher-than-average pressure sprawled across the North American Arctic and Greenland. These areas of high pressure act like boulders in a river. They slow and disrupt the normal westerly flow of the wind, forcing it to make, large, meandering detours to the north or south.

Average geopotential height anomaly at 700 millibar pressure level in Junes from 2007-2012 compared to the long-term average (1981-2010) based on NCEP reanalysis data provided by PSD at NOAA ESRL. Orange colors are higher-than-average pressure; blue is lower-than-average pressure.     Map by Dan Pisut, NOAA Environmental Visualization Lab.

Arctic oceanographer and his NOAA colleagues think these “blocking highs” on the North American side of the Arctic created the unusually strong southerly flow that brought warm air into the central Arctic and over Greenland. The persistent southerly winds would help explain both the record low sea ice extent in summer 2012, as well as the island-wide melting of the surface of the Greenland Ice Sheet, which satellites detected in July 2012.

“This story started with us trying to figure out why the sea ice extents of the past 6 years or so have been so much lower than we would expect based on the long-term warming trend alone,” says Overland, “and we think this unusual circulation of the Arctic atmosphere is major part of it.”

Why, asks Overland, have these high pressure patterns have been forming so consistently each June for the past six years? The repeated appearance of these atmospheric features each June is so unusual that it’s the equivalent of a 1-in-a-1000 event. Can this be attributed to natural variability?

Instead, Overland’s hunch is that the cause is a change in the atmosphere that is itself connected to climate change in some way, possibly linked to record and near-record low June snow cover in the Canadian Arctic in recent years. “We don’t know that part of the story yet,” he says, “but this would certainly be the type of amplification of climate change [warming triggers changes that lead to more warming] we have been expecting to see in the Arctic.”

References

- Arctic Sea Ice Getting Thinner, Younger
http://www.climatewatch.noaa.gov/article/2012/arctic-sea-ice-getting-thinner-younger

- June wind shift a little something extra behind recent Arctic ice losses
http://www.climatewatch.noaa.gov/article/2012/june-wind-shift-a-little-something-extra-behind-recent-arctic-ice-losses

- Poles apart: A record-breaking summer and winter
http://nsidc.org/arcticseaicenews/2012/10/poles-apart-a-record-breaking-summer-and-winter/

- PIOMAS Arctic Sea Ice Thickness Simulation 1978-2011, published Sep 14, 2012 by ArctischePinguin

https://www.youtube.com/watch?v=G1TLzgSlGtQ

Related

- Arctic summer wind shift
http://arctic-news.blogspot.com/2012/10/arctic-summer-wind-shift.html

- The recent shift in early summer Arctic atmospheric circulation
http://www.agu.org/pubs/crossref/2012/2012GL053268.shtml

- Presentation by Dr. Jennifer Francis, Rutgers University
https://www.youtube.com/watch?v=RtRvcXUIyZg
http://marine.rutgers.edu/~francis/pres/Francis_Vavrus_2012GL051000_pub.pdf

- Accelerated Warming in the Arctic
http://arctic-news.blogspot.com/2012/09/accelerated-warming-in-the-arctic.html

- Changes to Polar Vortex affect mile-deep ocean circulation patterns
http://arctic-news.blogspot.com/2012/09/changes-to-polar-vortex-affect-mile-deep-ocean-circulation-patterns.html

- Diagram of Doom
http://arctic-news.blogspot.com/2012/08/diagram-of-doom.html

- Opening further Doorways to Doom
http://arctic-news.blogspot.com/2012/08/opening-further-doorways-to-doom.html

- Opening the Doorways to Doom
http://arctic-news.blogspot.com/2012/08/opening-the-doorways-to-doom.html

- How extreme will it get?
http://arctic-news.blogspot.com/2012/07/how-extreme-will-it-get.html

Retreat Update

A bit of new info on one of David's latest film projects courtesy of Screen Daily:

Sony Pictures Home Entertainment has taken UK rights to Retreat, a Magnet Films project set to star Thandie Newton, Jason Isaacs and David Tennant.
Carl Tibbetts will make his feature directorial debut; Magnet’s Gary Sinyor produces.
Executive producers are David Frost & Michael Rosenberg.
The film is scheduled to shoot this summer in North Wales. The plot follows a couple who go to a remote island cottage to try to rebuild their marriage. Instead a stranger arrives on their doorstep with frightening news.
Dave G Bishop, Head of Acquisitions, Northern Europe, SPHE, said, “We’re excited to be working with Magnet Films on this fantastic project. Carl Tibbets has written a thrilling script that keeps you guessing to the very end and with such great British acting talent attached, we’re confident the film will be both a critical and commercial success.”
Gary Sinyor, Managing Director, Magnet Films, added, “Retreat has the potential to be not just a crowd pleaser, but also a critical success based on the intelligent page-turner of a script and the marquee cast.”

David Signs Up For Retreat

Magnet Films have announced that David is part of the cast for their new psychological thriller, Retreat.

Screen Daily reports:
Thandie Newton, Jason Isaacs and David Tennant are attached to star in Magnet Films’ psychological thriller Retreat.
The film, to be directed by newcomer Carl Tibbetts, follows a couple (played by Newton and Isaacs) who are seeking to rebuild their relationship by taking time out on a remote island but their peace is shattered when they find a man in military uniform (Tennant) half-dead on their doorstep who tells them there is a lethal virus killing millions on the mainland.
Tibbetts co-wrote the script with Janice Hallett and shooting is due to begin in May in Canada. In a last-ditch attempt to save their faltering marriage, 30-something professional couple Martin & Kate Badenoch retreat to the remote and unpopulated island of Dinnish, a place where they once shared a romantic idyll. It is autumn on the island.
The rocky, barren moors are blown by freezing winds and the generator in the couple’s cottage is failing. Anxieties are pushed higher when they lose all contact with the mainland, and find themselves inexplicably stranded and alone.
Suddenly a wounded armed American stranger collapses at their door with frightening news of cataclysmic events happening in the world outside. But who is this volatile, charismatic American? And is he telling the truth? Slowly, the couple become unwitting prisoners to the stranger’s will.
In a series of tense twists the captive couple use all their ingenuity to outwit the stranger and unravel the ‘truth’ about the outside world. But is the truth what they really want to hear? Loyalties divide and merge, paranoia runs high and conflicts bubble to the surface resulting in a violent and shocking conclusion.
Magnet Films producer Gary Sinyor said: “It reminded me of Dead Calm when I first read it. Only better. It’s got a similar sexual tension but the battle of wits between the characters and plot twists are constantly surprising. We’re delighted to have secured three of the UK’s most powerful actors.”
It is UK based Magnet Film’s first foray into thrillers, following romantic comedy In Your Dreams, rock and roll adventure The Story Of _ and football documentary In The Hands Of The Gods.

A short synopsis of the plot follows:
In a last-ditch attempt to save their faltering marriage, 30-something professional couple Martin & Kate Badenoch retreat to the remote and unpopulated island of Dinnish, a place where they once shared a romantic idyll. It is autumn on the island.
The rocky, barren moors are blown by freezing winds and the generator in the couple’s cottage is failing. Anxieties are pushed higher when they lose all contact with the mainland, and find themselves inexplicably stranded and alone.
Suddenly a wounded armed American stranger collapses at their door with frightening news of cataclysmic events happening in the world outside. But who is this volatile, charismatic American? And is he telling the truth? Slowly, the couple become unwitting prisoners to the stranger’s will.
In a series of tense twists the captive couple use all their ingenuity to outwit the stranger and unravel the ‘truth’ about the outside world. But is the truth what they really want to hear? Loyalties divide and merge, paranoia runs high and conflicts bubble to the surface resulting in a violent and shocking conclusion.

More info including storyboards can be seen here.