Antarctic Sea Ice Reaches New Record Maximum - Video

This year, Antarctic sea ice reached a record maximum extent while the Arctic reached a minimum extent in the ten lowest since satellite records began. Why are these trends going in opposite directions?

Image Credit: NASA Goddard Space Flight Center/Joy Ng

Sea ice surrounding Antarctica reached a new record high extent this year, covering more of the southern oceans than it has since scientists began a long-term satellite record to map sea ice extent in the late 1970s.

The upward trend in the Antarctic, however, is only about a third of the magnitude of the rapid loss of sea ice in the Arctic Ocean.

The new Antarctic sea ice record reflects the diversity and complexity of Earth’s environments, said NASA researchers.

Claire Parkinson, a senior scientist at NASA’s Goddard Space Flight Center, has referred to changes in sea ice coverage as a microcosm of global climate change.

Just as the temperatures in some regions of the planet are colder than average, even in our warming world, Antarctic sea ice has been increasing and bucking the overall trend of ice loss.

“The planet as a whole is doing what was expected in terms of warming. Sea ice as a whole is decreasing as expected, but just like with global warming, not every location with sea ice will have a downward trend in ice extent,” Parkinson said.

Since the late 1970s, the Arctic has lost an average of 20,800 square miles (53,900 square kilometers) of ice a year; the Antarctic has gained an average of 7,300 square miles (18,900 sq km).

On Sept. 19 this year, for the first time ever since 1979, Antarctic sea ice extent exceeded 7.72 million square miles (20 million square kilometers), according to the National Snow and Ice Data Center. The ice extent stayed above this benchmark extent for several days.

The average maximum extent between 1981 and 2010 was 7.23 million square miles (18.72 million square kilometers).

The single-day maximum extent this year was reached on Sept. 20, according to NSIDC data, when the sea ice covered  7.78 million square miles (20.14 million square kilometers).

This year's five-day average maximum was reached on Sept. 22, when sea ice covered 7.76 million square miles (20.11 million square kilometers), according to NSIDC.

On Sept. 19, 2014, the five-day average of Antarctic sea ice extent exceeded 20 million square kilometers for the first time since 1979, according to the National Snow and Ice Data Center (NSIDC). 

The red line shows the average maximum extent from 1979-2014.

Image Credit: NASA's Scientific Visualization Studio/Cindy Starr

A warming climate changes weather patterns, said Walt Meier, a research scientist at Goddard.

Sometimes those weather patterns will bring cooler air to some areas, and in the Antarctic, where sea ice circles the continent and covers such a large area, it doesn’t take that much additional ice extent to set a new record.

“Part of it is just the geography and geometry. With no northern barrier around the whole perimeter of the ice, the ice can easily expand if conditions are favorable,” he said.

Researchers are investigating a number of other possible explanations as well. One clue, Parkinson said, could be found around the Antarctic Peninsula, a finger of land stretching up toward South America.

There, the temperatures are warming, and in the Bellingshausen Sea just to the west of the peninsula the sea ice is shrinking.

Beyond the Bellingshausen Sea and past the Amundsen Sea, lies the Ross Sea, where much of the sea ice growth is occurring.

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