Researchers have measured a new record for sea-ice extent in the Antarctic. Why the white splendour is extending there while it is rapidly disappearing in the Arctic is a mystery.
Antarctica: The extent of sea ice (white) reached a record on 22 September. The yellow line shows the median of 1981 to 2000. Ice shelf is shown in gray.
Whenever the ice at the North and South Pole is mentioned, it is mostly in the context of melting ice triggered by global warming. However, the sea ice in Antarctica – in contrast to that in the Arctic – has proved to be remarkably robust. New measurements have now confirmed that. As the U.S. space agency NASA announced, the sea ice in the Antarctic has extended over an area of 19.47 million square meters at the end of September. That is the highest since measurements began in 1979.
The result is based on data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) on board of the Japanese satellite “GCOM-W1″. “The winter maximum has been a record for on the second consecutive year” said Walt Meier, a meteorologist at NASA’s Goddard Space Flight Center. However, he stressed that it is by no means a rapid growth: The now measured maximum extent is only 3.6 percent above the average maximum extent of 1981 to 2010. “This year, the ice edge extends therefore only 35 kilometres further out to sea than in an average year,” Meier said.
Moreover, the mere extent of sea ice does not necessarily say something about the volume of the ice, because that also depends on the thickness of the frozen layer. And the vast majority of the Antarctic ice mass is located on the Antarctic continent – and there the ice has decreased in recent years as a whole, particularly in West Antarctica.
But why the sea ice is increasing is a mystery. Scientists suspect that a change in the air currents could explain to a great extent the increase in Antarctic sea ice in recent decades. Other speculations are that ocean currents carry cooler surface water to the Antarctic or that the melting water, which flows through massive channels in the ice, decreases the temperature of the surface sea water.
Translation by Philipp Mueller
See full article at Spiegel Online, 21 October 2013
Press Release: Arctic sea ice avoids last year’s record low; Antarctic sea ice edges out last year’s high
The National Snow and Ice Data Center (NSIDC) is part of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. NSIDC scientists provide Arctic Sea Ice News & Analysis content, with partial support from NASA.
This September, sea ice covering the Arctic Ocean fell to the sixth lowest extent in the satellite record, which began in 1979. All of the seven lowest extents have occurred in the last seven years, since 2007. Satellite data analyzed by NSIDC scientists showed that the sea ice cover reached its lowest extent on September 13. Sea ice extent averaged for the month of September was also the sixth lowest in the satellite record.
“A relatively cool and stormy summer helped slow ice loss compared to the last few summers,” said NSIDC scientist Julienne Stroeve. In contrast to 2012, when sea ice reached a new record low in the satellite record, cooler conditions in the Arctic this summer helped to retain more sea ice. “This summer’s extent highlights the complex interaction between natural climate variability and long-term thinning of the ice cover,” Stroeve said.
“For Earth’s ice and snow cover taken as a whole, this year has been a bit of a bright spot within a long-term sobering trend,” said NSIDC director and senior scientist Mark Serreze.
Arctic sea ice, however, continues to be thinner than in past years, as confirmed by direct satellite observations and estimates of ice age, and therefore more vulnerable to breakup by storms, circulating currents, and melt. “While Earth’s cryosphere, that is, its snow and ice cover, got a shot of hope this year, it’s likely to be only a short-term boost,” Serreze said. While most of the ice cover now consists of young, thin ice, a pack of multiyear ice remains in the central Arctic. Multiyear ice is ice that has survived more than one melt season and is thicker than first-year ice.
Arctic sea ice extent reached its lowest point this year on September 13, 2013 when sea ice extent dropped to 5.10 million square kilometers (1.97 million square miles). Averaged over the month of September, ice extent was 5.35 million square kilometers (2.07 million square miles). This places 2013 as the sixth lowest ice extent, both for the daily minimum extent and the monthly average. September ice extent was 1.17 million square kilometers (452,000 square miles) below the 1981 to 2010 average.
The Arctic ice cap grows each winter as the sun sets for several months and shrinks each summer as the sun rises higher in the northern sky. Each year the Arctic sea ice reaches its annual minimum extent in September. It hit a new record low in 2012. This summer’s low ice extent continued the downward trend seen over the last thirty-four years. Scientists attribute this trend in large part to warming temperatures caused by climate change. Since 1979, September Arctic sea ice extent has declined by 13.7 percent per decade. Summer sea ice extent is important because, among other things, it reflects sunlight, keeping the Arctic region cool and moderating global climate.
In addition to the decline in sea ice extent, a two-dimensional measure of the ice cover, the ice cover has grown thinner and less resistant to summer melt. Recent data on the age of sea ice, which scientists use to estimate the thickness of the ice cover, shows that the youngest, thinnest ice, which has survived only one or two melt seasons, now makes up the majority of the ice cover.
As the Arctic was reaching its minimum extent for the year, Antarctic sea ice was reaching record high levels, culminating in a Southern Hemisphere winter maximum extent of 19.47 million square kilometers (7.52 million square miles) on September 22. The September 2013 monthly average was also a record high, at 19.77 million square kilometers (7.63 million square miles) slightly higher than the previous record in 2012. Scientists largely attribute the increase in Antarctic sea ice extent to stronger circumpolar winds, which blow the sea ice outward, increasing extent.
In contrast to the sharp downward trend in September Arctic sea ice, Antarctic September sea ice has been increasing at 1.1 percent per decade relative to the 1981 to 2010 average. “The tiny gain in Antarctica’s ice is an interesting puzzle for scientists,” said NSIDC lead scientist Ted Scambos. “The rapid loss of ice in the Arctic should be ringing alarm bells for everyone.”
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PRH says:
November 6, 2013 at 4:32 pm
And this is a problem?
And “bumper crops” is relevant to the growing ice extent around Antarctica?
By the way, at today’s rates of growth, MUCH more than 35 km per year, the Strait of Magellan and Cape Horn could be blocked by sea ice from Antarctica in as few as 8-10 years.
The NSIDC’s premise, their life’s work in supporting CAGW religion is false.
ALL of the exaggerated CAGW hype about sea ice melting is based on the supposed “extra heat absorbed” by open ocean water compared to that solar energy reflected by pristine sea ice. Supposedly, if the sea ice goes away, more energy is absorbed, the water heat more, more ice is melted, more open ocean is exposed, and more sea is melted.
But that doesn’t happen. After 2007’s very low sea ice extents up north, sea ice in 2008, 2009, 2010, 2011 increased. NO season-to-season effect.
After the record low 2012 sea ice extents, sea ice in 2013 expanded more than it had been since 2006! The myth of any arctic sea ice death spiral is a lie used to take your money and justify policies that kill people by increasing energy prices and reducing worldwide health, food, and security: food, fuel, fodder, fruit, fiber, and farms.
On the other hand, reduced ice area in the arctic occurs in mid-September between 75 and 83 degrees north latitude. At these latitudes at this time of year, the sun is NEVER higher than 15 degrees above the horizon, and most of the time that it is above the horizon, it is between 4 and 10 degrees up. At these low solar elevation angles, the albedo of open ocean is 0.30 – 0.40, very close to that of the melting sea ice (0.65 to 0.60), and so little difference in heat absorption actually happens during the few hours each day when the sun is actually above the horizon. Worse, heat LOSS from the exposed open ocean (evaporation, convection, conduction, radiation) are ALL greater compared to what is lost when sea ice blankets the water, AND those increased heat losses when the sea ice is lost are continuous, 24-hours-per-day events.
Thus, loss of additional arctic sea ice in September from the normal COOLS the planet.
But Antarctic sea ice is expanding between 60 degrees and 58 degrees south latitude – NOT at 78, 80, or 82 degrees north latitude: At 60 south latitude, the sun is much higher in the sky, penetrating much less atmosphere, and IS reflecting much more solar energy!
Thus, exactly contrary to their statements of the CAGW religion, more energy is reflected from the planet by increased antarctic sea ice, more energy is lost from the planet by decreased arctic sea ice … and the planet faces even more cooling.
But it is even worse than they want!
There is “only” 3.5 million sq km’s of arctic sea ice left to melt from 2012’s record low. Once that melts – IF it ever melts, there simply is no more that could be lost. Thus, a plausible loss of 1,000,000 sq km’s next year (loss of 30% of the sea ice!) would be preceded by the screaming headlines and might even be followed by another 1,000,000 the next year. And perhaps another. But each loss of Arctic sea ice from today’s levels in September merely increases the LOSS of net energy from the planet. You could never “melt’ more than that 3.5 million sq km’s that was the record last year.
But, in the Antarctic, the 19.5 million sq km’s of sea ice surrounds a land area of 14 millions sq km’s of 97% ice, and has 1.5 million more permanent shelf ice. Net? Antarctic “total ice” this year is 35 million sq km’s … AND THERE IS NO MAXIMUM LIMIT.
So, a “minor gain” of 1.0 million sq km’s is less than a 3% increase, right?