The Danish Meteorological Institute shows a 63% increase in Arctic sea ice extent since the same date in 2012, and an increase of 76% since the 2012 summer minimum. Current extent is 4.4 million km², up from 2.7 million km² on August 28, 2012.
Sea ice extent in recent years (in million km2) for the northern hemisphere, as a function of date.
My methodology is similar numerically to DMI’s, I used maps from the Japan Aerospace Exploration Agency to generate the map below. Green shows ice gain since the same date in 2012, and red shows ice loss. My calculation shows a 64% increase in ice, almost identical to the calculations from DMI.
A favorite comment from alarmists is “the increase in ice extent is meaningless, because the ice is getting thinner”
They have it exactly backwards. The reason why ice extent is up, is because the ice is thicker. The animation below, based on maps from NSIDC, shows the movement of older, thicker ice into the western Arctic over the past two years. The color scale represents the age of the ice – i.e. five year old ice is red. You can see how older, thicker ice is moving towards Alaska, and accumulating. The amount of five year old ice has more than doubled over the past two years.
Starting in 1988, winter winds began pushing older, thicker ice out into the North Atlantic. This went on until a few years ago, and caused the lower summer minimums seen over the past 15 years. Younger, thinner ice melts out more easily in the summer.
But since 2011, the winter winds have reversed. Ice is now getting pushed away from the Atlantic side, and is accumulating on the Pacific side – where it is preserved. If this wind pattern continues for a few more years, summer ice extent will soon return to the levels seen in the 1980’s.
A few years ago, experts claimed that all of the older thicker ice had disappeared. As usual, they had absolutely no clue what they were talking about.
(Reuters) – The multiyear ice covering the Arctic Ocean has effectively vanished, a startling development that will make it easier to open up polar shipping routes, an Arctic expert said on Thursday.
Vast sheets of impenetrable multiyear ice, which can reach up to 80 meters (260 feet) thick, have for centuries blocked the path of ships seeking a quick short cut through the fabled Northwest Passage from the Atlantic to the Pacific. They also ruled out the idea of sailing across the top of the world.
But David Barber, Canada’s Research Chair in Arctic System Science at the University of Manitoba, said the ice was melting at an extraordinarily fast rate.
“We are almost out of multiyear sea ice in the northern hemisphere,” he said in a presentation in Parliament. The little that remains is jammed up against Canada’s Arctic archipelago, far from potential shipping routes.
Scientists link higher Arctic temperatures and melting sea ice to the greenhouse gas emissions blamed for global warming.
The ice loss was caused by winter winds pushing the thicker ice out into the North Atlantic. Unless “scientists” can link “greenhouse gas emissions” to the direction of Arctic winter winds, they probably shouldn’t lie about the state of their knowledge.