Ice, ice, baby: Arctic sea ice on the rebound

Good news from the Arctic. Sea ice extent (area covered by ice) is at a seven-year high. It’s nearly back to within one standard deviation of the 30 year normal at 14.25 million square kilometers. This year's ice extent is the highest since 2006 at this point in the year. Temperatures in the arctic remain well below freezing and should remain there through March. So, more ice should be added in the next few weeks. We are nearing the peak of sea ice in the Northern Hemisphere. Once April roles around, warmer temperatures will move north from the equator. That's when ice extent will begin its yearly decline toward mid-summer. I bet you didn't expect to hear that, especially after the record melt a few years ago. Back in 2007, sea ice extent dropped to its lowest point in the satellite history. Since then, arctic ice extent has increased. A lot has been made of disappearing Arctic sea ice and the prospects of ice-free summers due to global warming. But, let’s put that into perspective. The problem with much of this debate is the fact that accurate ice measurements go back only a few decades. Satellite measurements date back only to 1979 for Arctic sea ice, so accurate data is barely 30 years old. So, what was the state of Arctic sea ice before then? We just don't know. We have anecdotal evidence that shows the arctic with much less ice than we see today. Back in November 1922, The Monthly Weather Review reported on unusually warm temperatures and rapid ice melt in the arctic. "So little ice has never been seen before." In fact, scientific exploration that took place in August 1922, sailed in open water all the way to 81° 29 minutes North in ice free waters. This was the "farthest north ever reached with modern oceanographic apparatus." Another famous photo comes from the cold war days. The submarine, USS Skate, actually surfaced at the North Pole in ice free water back in the summer of 1958. There is no open water at the North Pole now, nor has there been in the modern satellite record. One crew member, James Hester, aboard the USS Skate remembers said, “the Skate found open water both in the summer and following winter. We surfaced near the North Pole in the winter through thin ice less than 2 feet thick." And there are more examples. If we listen to some scientists, the situation is getting worse. Back in 1947, Dr. Hans Ahlmann, a Swedish physicist, predicted the catastrophic loss of sea ice within a few years. In 1969, The New York Times predicted the Arctic would be ice-free by 1970. In 2008, Dr. Olav Orheim, head of the Norwegian International Polar Year Secretariat, said the Arctic would be ice-free by that same summer. Other prediction suggested the demise of North Pole ice by 2010, 2011, and now 2013 and 2015, and so on. There is still ice covering the arctic; a large amount of ice. The latest bad news from the arctic comes from NASA. This week they announced that older, thicker, multi-year ice is in decline. “The average thickness of the Arctic sea ice cover is declining because it is rapidly losing its thick component, the multi-year ice. At the same time, the surface temperature in the Arctic is going up, which results in a shorter ice-forming season." That has been true since satellite records began, a mere 32 years ago. But, the latest measurements show that multi-year sea ice has increased since 2007. That's more good news. There are also many explanations for the recent fluctuations in ice thickness and extent. Back in 2010, Dr. Fredrik Ljungqvist used temperature reconstructions for the last 2000 years and discovered alternating warm and cold periods affecting the northern latitudes that were several hundred years long. Suggestions by NASA in 2007, in Smedsrud Et Al 2011 and recently in research by Wang, Song, and Curry suggest that wind patterns are a big factor in the Arctic puzzle. There’s also direct evidence that soot from the industrialization of Asia is collecting in the Arctic and could be a factor in albedo changes in the Arctic which contribute to ice loss. Ocean current circulations have also been shown to break up thicker ice and shift it into warmer ocean areas. So, the bottom line is Arctic sea ice is effected by a variety of naturally occurring factors that cycle over years or decades. Without accurate measurements from a much longer time frame, it is impossible to tell whether ice loss over the last few decades is out of the ordinary. It is also impossible to accurately extrapolate the gain or loss of sea ice out several decades into the future. Arctic sea ice extent and thickness will likely ebb and flow with changes in these significant occurrences.