Arctic Sea Ice Extent is Third Lowest on Record
Written by Nancy Atkinson
U.S. satellite measurements show Arctic sea ice extent in 2009 – the area of the Arctic Ocean covered by floating ice – was the third lowest since satellite measurements were first made in 1979. While the ice area at minimum was an increase from the past two years, it is still well below the average for the past 30 years. In the video above, Tom Wagner, NASA's cryosphere program manager, describes the shrinking of Arctic sea ice and the significance of the problem for the rest of the planet.
Arctic sea ice reached its minimum extent around September 12, as shown in the image and video below/above. According to scientists affiliated with the National Snow and Ice Data Center (NSIDC), sea ice coverage dropped to 5.10 million square kilometers (1.97 million square miles) at its minimum. The ice cover was 970,000 square kilometers (370,000 square miles) greater than the record low of 2007 and 580,000 square kilometers (220,000 square miles) greater than 2008.
NSIDC is sponsored by several U.S. government agencies, including NASA. Ice data are derived from measurements made by U.S. Department of Defense and NASA satellites, with key work in interpreting the data and developing the 30-year history done by scientists at NASA's Goddard Space Flight Center in Greenbelt, Md.
"The changes from year to year are interesting since there has been large variability," said Josefino Comiso, a sea ice expert at NASA Goddard. "But we need to look at several years of data to examine the long-term trends."
Click here to watch a visualization of the sea ice changing over a four-year period.
"Our three decades of continuous satellite measurements show a rapid decline of about 11.6 percent per decade," Comiso said. Arctic sea ice has declined about 34 percent since measurements were first made in the late 1970s.
The four lowest ice extents on record have occurred between 2005 and 2009, with the record minimum reached during a dramatic drop in ice cover in 2007 that was exacerbated by unusual polar winds.
Several recent studies based on data from NASA’s ICESat and QuikScat satellites have shown that, in addition to shrinking geographic ice coverage, the amount of multi-year ice cover – thicker ice that survives more than one summer — has been declining in recent years.
"The oceans are crucial to Earth's climate system, since they store huge amounts of heat," said Comiso. "Changes in sea ice cover can lead to circulation changes not just in the Arctic Ocean, but also in the Atlantic and Pacific oceans. If you change ocean circulation, you change the world's climate."
Each winter existing sea ice thickens and new, thinner ice is formed. This conceptual animation shows a cutaway view of the seasonal advance and retreat of Arctic sea ice, demonstrating the current trend toward a thinning ice pack, with less of the thicker multi-year ice surviving each summer's melt. Changes in the Arctic ice cover could also mean a new paradigm for life in the sea. "The waters at high latitudes are some of the most biologically productive in the world because of the presence of sea ice," Comiso added. "Many of our richest fisheries are the seas around the Arctic Ocean, and we don't know what the consequences might be if the seasonal sea ice disappears in these regions."
Source: NASA
Filed under: Earth Observation
Tags: Artic Sea Ice, Earth ObservationRelated stories on Universe Today
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October 6th, 2009 at 2:25 pm
Sea Ice Ends Year at Same Level as 1979 (posted In Daily Tech January 1, 2009)
“Rapid growth spurt leaves amount of ice at levels seen 29 years ago.
“Thanks to a rapid rebound in recent months, global sea ice levels now equal those seen 29 years ago, when the year 1979 also drew to a close.
“Ice levels had been tracking lower throughout much of 2008, but rapidly recovered in the last quarter. In fact, the rate of increase from September onward is the fastest rate of change on record, either upwards or downwards.
“The data is being reported by the University of Illinois's Arctic Climate Research Center, and is derived from satellite observations of the Northern and Southern hemisphere polar regions.
“Each year, millions of square kilometers of sea ice melt and refreeze. However, the mean ice anomaly — defined as the seasonally-adjusted difference between the current value and the average from 1979-2000, varies much more slowly. That anomaly now stands at just under zero, a value identical to one recorded at the end of 1979, the year satellite record-keeping began.”
October 6th, 2009 at 8:38 pm
hey dont forget this news
http://www.spitzer.caltech.edu/Media/releases/ssc2009-19/release.shtml
October 7th, 2009 at 3:55 am
Nice propaganda video. Short on facts, long on animations.
Hanson and his crew are so tainted by his taking funds from George Soros' Open Society Institute that I wouldn't believe a word they said under any circumstances.
October 7th, 2009 at 7:05 am
Not that one can correlate weather with climate, but it's a funny coincidence that the slight increase 2009 correlates with the slight 2008 global temp decrease. Which in turn can putatively be blamed on the long solar cycle minimum. Maybe one can tease out such effects.
@ Amos:
"observations of the Northern and Southern hemisphere polar regions."
Comparing apples and pears much? We need data on Northern regions in isolation to make a comparison with old data.
Also, you are cherry picking:
"Earlier this year, predictions were rife that the North Pole could melt entirely in 2008. Instead, the Arctic ice saw a substantial recovery. Bill Chapman, a researcher with the UIUC's Arctic Center, tells DailyTech this was due in part to colder temperatures in the region. Chapman says wind patterns have also been weaker this year. Strong winds can slow ice formation as well as forcing ice into warmer waters where it will melt.
Why were predictions so wrong? Researchers had expected the newer sea ice, which is thinner, to be less resilient and melt easier. Instead, the thinner ice had less snow cover to insulate it from the bitterly cold air, and therefore grew much faster than expected, according to the National Snow and Ice Data Center."
That article confirms this one. And vice versa.
October 7th, 2009 at 7:12 am
DanNy, don't you mean James Hansen?
But he works for NASA. Not that it matters, because the argument is an association fallacy or more generally a red herring.
October 7th, 2009 at 8:11 am
Universe Today should be more selective in the articles it posts. It should stick to science and avoid the politics, and especially scientists, who allow their work to be skewered by their politics. Many of Universe Today's readers look to it for information, knowledge and understanding of scientific matters. They can be easily misled by the subtle bias propagated by those in the field of science, who prostitute their work to serve their ideological agenda.
October 7th, 2009 at 8:41 am
Ditto what Amos says. Nancy can't help it.
October 7th, 2009 at 8:45 am
Also ditto what Amos says.
October 7th, 2009 at 7:15 pm
OT:
@ herr larsson
thanks for the fallacy link. very informative. i can't wait to invoke a few of those with a particular friend of mine.
October 8th, 2009 at 7:50 pm
This is science people, and the AAAS publishes every week article by climatologists from universities , NASA and NOAA on this topic. The evidence is pretty clear on this. This is science, and we are adjusting the climate of the planet. Politics might be used to do something about this, or to conceal what is happening and tell lies.
LC
October 9th, 2009 at 4:11 am
LC, as much as I hate to be drawn into a discussion on this topic, this is not science.
I understand what you are saying but please don't blindly take other peoples interpretation of evidence or theories as set in stone fact, nothing is.
Large conclusions are being drawn from a tiny amount of evidence and being formed into weak theories.
My problem is that some people are acting on these weak theories, and trying to diffuse or solve a situation they know little about.
You know and we all know that we need a lot more evidence, if we want to try to understand the basics of global weather systems.