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article imageSea ice extent at both poles has scientists shaking their heads

By Karen Graham     Nov 2, 2013 in Environment
The earth's sea and ice cover is not a static thing, but changes continually. This year is a good example, with Antarctic sea ice extent setting a growth record, while the Arctic sea ice did better than 2012's record low sea ice extent.
NASA researchers announced two weeks ago that the sea ice growth in the Antarctic region has set a new record, reaching 7.53 million sq. mi., surpassing the 2012 record of 7.51 million sq. mi., at the end of September. The end of September signals the end of winter in the Antarctic, and conversely, the end of September at the North Pole signals the end of summer.
Scientists were a little surprised at the sea ice extent in the Arctic Ocean this year, too. In 2012, the September minimum sea ice extent averaged 1.32 million sq. mi., the lowest ever recorded since satellite monitoring began in 1979. The Arctic sea ice reached its minimum extent on Sept. 13, this year and covered 1.97 million sq. mi.
Researchers are calling this year's increase a sharp recovery after the record low of 2012. But they also temper this by pointing out that this years figures still make it the sixth lowest reading since satellite tracking began. NASA scientist Walt Meier, who has been monitoring the sea ice in the Arctic for years, said, "I'm not surprised there was a jump upward, we've never set two record lows in a row."
Scientists say the increase in sea ice at poles does not contradict Global Warming
The Arctic Ocean and North Pole
The condition of the ice at the North Pole is still thin and slushy, not the thick ice seen in the past. This makes the ice quicker to melt, and doesn't change the overall long-term decline. NOAA scientists point to the colder and cloudier spring and summer in the Arctic regions this year as favoring the formation of more ice.
Global warming: Arctic Sea Ice Shrinks - 04/23/2013.
Global warming: Arctic Sea Ice Shrinks - 04/23/2013.
www.nasa.gov/
Over the next generation the world will continue to see a decline of the Arctic ice cap (Notice the yellow line in the picture above, marking the extent of the ice in past years), and in the not so distant future, summers will see the Arctic region with no ice. This will not be the cause of rising sea levels because the ice is already floating, and displaces its weight in the water. It's the same as putting ice cubes in a bowl of water. The ice will eventually melt, but the water will not overflow the bowl.
It does mean the replacement of white ice with dark water means the Arctic Ocean can absorb more heat from the sun in the summer. The heat from the sun also contributes to the melting of nearby land ice, such as in Greenland, which will add to rising sea levels.
Antarctica the South Pole
Again, scientists are saying the record-breaking growth of the sea ice at the South Pole does not mean Global Warming should be dismissed. It's important to remember the Antarctic sea ice encircles a frozen continent. There are also several other factors playing a role in the growth of the ice also, such as warming air temperatures, winds and even the ozone hole.
Antarctic sea  ice extent as of 04/23/2013.
Antarctic sea ice extent as of 04/23/2013.
www.nasa.gov/
Winds have been found to play the biggest role in the size of the ice pack, more so than air temperatures or the ocean currents. This is based on a study published on Nov. 11, 2012 in the journal, "Nature Geoscience."
Very strong circumpolar winds come blowing off the frozen continent, carrying frigid air to the sea. This freezes the ocean surface pushing the ice around. It is pointed out the latest sea ice extent in the Antarctic is only 3.6 percent above the average extent of 1981-2010. Another thing to take into consideration is the volume of the ice. Scientists again point out that most of the ice is on a frozen land mass, and there, the ice has been decreasing over the past several years.
Scientists are still sorting through a number of reasons for the huge growth of the Antarctic sea ice, and there may not be a ready answer. Sea ice is a complex mixture, and there are a number of variables to consider. The main issue is still Global Warming, and this is one issue that is not going away, ice or no ice.
More about Arctic ocean, Antarctica, sea ice extent, Global warming, NOAA
 
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