With the annual pullback of Arctic Ocean sea ice at an end, it’s clear that this year’s retreat is nowhere near the satellite-era record set in 2012, but it’s also clear that there is still a long-term trajectory toward a largely open-water Arctic in summers in coming decades.
The image above is from The Cryosphere Today, a valuable Website maintained by William Chapman and others at the University of Illinois, Urbana-Champaign. The National Snow and Ice Data Center has not quite officially called the “minimum,” but it is nigh.
In a story on the Arctic ice season in The Guardian, Julienne Stroeve of the National Snow and Ice Data Center put it well: Read more…
11:44 p.m. | Updates from several scientists below |
The planet is warming and the Arctic is warming the most, as long foreseen by scientists in a climate system pushed out of balance through the rapid buildup of heat-trapping greenhouse gases in the atmosphere. One result is greater loss of Arctic sea ice in the annual summer warmup.
Today, the National Snow and Ice Data Center announced that the annual summer retreat of Arctic Ocean sea ice had reached a new low for the 33-year satellite era of careful monitoring (1.58 million square miles, or 4.1 million square kilometers), and there is still another week or two of melting before the typical summer ice minimum occurs.
This quote in the release from Walt Meier of the ice center efficiently encapsulates the context:
By itself it’s just a number, and occasionally records are going to get set. But in the context of what’s happened in the last several years and throughout the satellite record, it’s an indication that the Arctic sea ice cover is fundamentally changing.
The animated sea-ice imagery above — from one of two autonomous cameras set on ice near the North Pole each spring — gives a close-focus view of the slushy conditions that develop on the shifting ice when the summer sun is at its peak. (This is part of the annual North Pole Environmental Observatory project that I reported on in 2003; the cameras drift with the ice through the summer and are currently over the shoulder of Greenland. You can track their position here.)
Over all, the analysts as a group see no deviation from the long-term trend toward thinning and dwindling summer sea ice given how the Arctic tends to amplify the long-term global warming trend. Here’s how the summary put it: “The June 2010 Outlook indicates a continuation of the overall trend in long-term loss of summer Arctic sea ice, with no indication that a return to historical levels of the 1980s/1990s will occur.”
Keep in mind that this effort is portrayed as experimental — not the kind of forecasts that companies pondering Arctic shipping routes should use to set their polar transit schedules. The goal, the scientists say, is to compare independent methods of gauging ice trends from factors including sea temperature, ice thickness and cycles of atmospheric pressure and winds around the Arctic.
The full report includes a long but interesting section on conditions this spring, including statements from many of the individual researchers: Read more…
The following video gives you a fascinating view of one patch of sea ice through 90 days, provided by a webcam left behind by researchers who annually set up camp near the North Pole to check ocean and ice conditions up close.
The new analysis, published in the Journal of Geophysical Research on Tuesday, is the latest of many findings supporting the idea that the region has shifted to a new state in which seasonal ice, which forms in winter and melts in the summer, dominates. This is the main reason biologists have concerns for the long-term welfare of polar bears, which have a harder time sustaining their weight and reproducing when summertime ice is thin. At the same time, the shift bodes well for shippers, like the German company Beluga, that have plans to start sending goods from Asia to northern Europe through the fabled, but long impassible, Northern Sea Route over Russia. Read more…
Here’s a quick swing north. The National Snow and Ice Data Center has inaugurated a useful new Web feature, Icelights, that offers the public a two-way portal for addressing questions about the behavior of sea ice and ice sheets and their relationship to the world far from the poles. The latest feature, “What is the connection between Arctic sea ice and U.S. weather?,” explores the hypothesis that open Arctic waters in fall or winter could influence storm patterns and snowfall outside of the region.
The answer? Unknown, so far. Here’s the most relevant line:
[W]hile sea ice affects the atmosphere, the atmosphere also affects sea ice. Warmer air temperatures help prevent ocean water from freezing over in the first place, and winds can push the ice together, keeping ice extent lower. “It’s a highly coupled system,” said NSIDC Director Mark Serreze, “Cause and effect are difficult to unravel.”
There’s also new analysis by a team from the Naval Postgraduate school, led by Wieslaw Maslowski, pointing to a complete late-summer retreat of Arctic Ocean sea ice by the end of this decade and possibly 2016. This is an initial finding reported by Maslowski at the European Geosciences Union (EGU) annual meeting and reported by Richard Black of the BBC, and there are plenty of ice analysts who doubt this conclusion and see more evidence of an open-water Arctic Ocean toward mid-century. The new analysis hinged on refined simulations and better incorporation of data on the thickness of ice. But the challenge, as noted in Black’s piece, is that thin ice — which both melts and reforms quickly — makes the behavior of the system harder to predict. The science of predicting sea ice behavior in a warming world is still in early stages of understanding, and a good place to keep track of the learning curve is through the Sea Ice Outlook project, which I’ve covered periodically.
I was lucky enough to observe the complicated nature of Arctic Ocean sea ice by camping on it for three days with a research team eight years ago this month:
Where Siberian snow cover and therefore the model has its best skill, the Eastern U.S., it correctly predicted cold, with the coldest temperatures extending from the Northern Plains through the Northeast. The model did incorrectly predict warm for the Southwestern U.S. The relatively warmest temperatures in the country were observed in the Southwest, though they were not warm compared with climatology. And certainly the AER forecast was better than any other forecast that I am aware of; no other forecast predicted a cold winter in the Eastern U.S., including that from the [National Oceanic and Atmospheric Administration].
1:54 p.m. | Updated The sun rose over the horizon at the North Pole last weekend and the six-month “day” just began there, making this a good time to check in on ice and climate trends up north. I can’t believe it’s seven years now since I spent three days camped on the ice pack near 90 degrees North with a rugged team of climate and cryosphere researchers trying to improve understanding of the complex interface between air, ice and water.
The latest research shows that while a decades-long trend toward thinner and sparser ice looks to continue, with warming from greenhouse gases and soot contributing to the change, expect a lot of variability along the way to a projected open-water summertime Arctic.
When the extent of the pack of sea ice drifting around the North Pole hit a remarkable low in 2007 (animation below), the resulting, and persistent, front-page thought was that the system was in a “death spiral” far more dramatic than any climate model had foreseen.
Even in 2007, some Arctic climate and ice specialists were warning that the ice retreat was “as much a result of ice moving as melting,” adding that the unpredicted changes could just as easily betray weaknesses in climate models as hints of some accelerating meltdown.
A new study scheduled for publication in Geophysical Research Letters supports the earlier research on the importance of winds in shaping the fate of sea ice both year to year and over recent decades. Read more…
There is rising concern among polar bear biologists that the big recent summertime retreats of sea ice in the Arctic are already harming some populations of these seal-hunting predators. That was one conclusion of the Polar Bear Specialist Group, a network of bear experts who met last week in Copenhagen to review the latest data (and data gaps) on the 19 discrete populations of polar bears around the Arctic. The group, part of the International Union for Conservation of Nature, includes biologists in academia and government and at nonprofit conservation organizations. Only one bear population is increasing (in the Canadian high Arctic), while eight are declining in numbers, the scientists said. At its last meeting, in 2005, the group concluded that five populations were in decline. Three populations appear to be stable and seven are too poorly monitored to gauge a trend.
The data gaps exist in important regions, including the Russian Arctic, where there are no ongoing population studies despite poaching problems. The group said that in Canada, home to two-thirds of the world’s polar bears, population studies have been so sporadic that there is no reliable way to track trends. The meeting was not without controversy. Mitchell Taylor, a Canadian expert on polar bears who was in the specialists’ group for many years, told some reporters that he was excluded this year because he disputes that the bears are in danger and that human-caused global warming poses a substantial threat to them. But Andrew Derocher, the current chairman of the group, wrote a detailed rebuttal on Tim Lambert’s Deltoid blog rejecting the assertions.
While pressing for cuts in greenhouse-gas emissions and better efforts to control hunting, both legal and illegal, the participating scientists concluded on an optimistic note, saying they were “optimistic that humans can mitigate the effects of global warming and other threats to polar bears, and ensure that they remain a part of the Arctic ecosystem in perpetuity.”
For the latest forecasts of this summer’s Arctic ice retreat, have a look at Sea Ice Outlook 2009, an effort to collate and compare a variety of studies aiming to project the minimum ice extent each summer. There is a strong consensus that the ice will remain well below the average recorded for the last three decades and that there is “no indication that a return to historical levels will occur.”
Given the unpredictable short-term dynamics up there, which make the ice subject to vagaries of Siberian winds and a mix of currents, a lot of polar ice experts tell me it’s pretty much impossible to make such a prediction with high confidence. In fact, the Independent’s story — the opening sentences and headline at least — go way beyond what Mark Serreze of the National Snow and Ice Data Center tells the reporter. As early as May, ice experts were putting good odds on having open water at the North Pole. [UPDATE 11 p.m.: Gavin Schmidt of Realclimate.org muses on why the media hyperventilate over polar non-news developments.]
One way or the other, it’s clear that, by the end of the 1990s, the veneer of ice on the Arctic Ocean had shifted to a far more tenuous state, with ever less thick, years-old ice like the floes I camped on when I went with the team setting up the annual North Pole Environmental Observatory. The animation above shows that the ice was flushed out, not melted.
Most of the seasoned Arctic ice experts I’ve canvassed for recent stories see the region exhibiting a mix of natural variability in the ice (like the flushing process) and a long-term trend toward less of it in summer, and more of it being fresh-made each season, and thus thin and easy to melt. Most also are convinced the change is now at least partly driven by human-caused global warming. Read more…