#ClimateChange: 2016 Arctic Sea Ice Wintertime Extent Hits Another Record Low — @NASA

From NASA:

Arctic sea ice appears to have reached a record low wintertime maximum extent for the second year in a row, according to scientists at the NASA-supported National Snow and Ice Data Center (NSIDC) and NASA.

Arctic sea ice was at a record low wintertime maximum extent for the second straight year. At 5.607 million square miles, it is the lowest maximum extent in the satellite record, and 431,000 square miles below the 1981 to 2010 average maximum extent. Credits: NASA Goddard's Scientific Visualization Studio/C. Starr
Arctic sea ice was at a record low wintertime maximum extent for the second straight year. At 5.607 million square miles, it is the lowest maximum extent in the satellite record, and 431,000 square miles below the 1981 to 2010 average maximum extent. Credits: NASA Goddard’s Scientific Visualization Studio/C. Starr

Every year, the cap of frozen seawater floating on top of the Arctic Ocean and its neighboring seas melts during the spring and summer and grows back in the fall and winter months, reaching its maximum yearly extent between February and April. On March 24, Arctic sea ice extent peaked at 5.607 million square miles (14.52 million square kilometers), a new record low winter maximum extent in the satellite record that started in 1979. It is slightly smaller than the previous record low maximum extent of 5.612 million square miles (14.54 million square kilometers) that occurred last year. The 13 smallest maximum extents on the satellite record have happened in the last 13 years.

This short animation shows the Arctic sea ice freeze cycle from the last summertime minimum extent to March 24, when it reached its wintertime maximum extent. Credits: NASA Goddard’s Scientific Visualization Studio/C. Starr

The new record low follows record high temperatures in December, January and February around the globe and in the Arctic. The atmospheric warmth probably contributed to this lowest maximum extent, with air temperatures up to 10 degrees Fahrenheit above average at the edges of the ice pack where sea ice is thin, said Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The wind patterns in the Arctic during January and February were also unfavorable to ice growth because they brought warm air from the south and prevented expansion of the ice cover. But ultimately, what will likely play a bigger role in the future trend of Arctic maximum extents is warming ocean waters, Meier said.

“It is likely that we’re going to keep seeing smaller wintertime maximums in the future because in addition to a warmer atmosphere, the ocean has also warmed up. That warmer ocean will not let the ice edge expand as far south as it used to,” Meier said. “Although the maximum reach of the sea ice can vary a lot each year depending on winter weather conditions, we’re seeing a significant downward trend, and that’s ultimately related to the warming atmosphere and oceans.” Since 1979, that trend has led to a loss of 620,000 square miles of winter sea ice cover, an area more than twice the size of Texas.

This year’s record low sea ice maximum extent will not necessarily result in a subsequent record low summertime minimum extent, Meier said. Summer weather conditions have a larger impact than the extent of the winter maximum in the outcome of each year’s melt season; warm temperatures and summer storms make the ice melt fast, while if a summer is cool, the melt slows down.

Arctic sea ice plays an important role in maintaining Earth’s temperature—its bright white surface reflects solar energy that the ocean would otherwise absorb. But this effect is more relevant in the summer, when the sun is high in the sky in the Arctic, than in the winter, when the sun doesn’t rise for months within the Arctic Circle. In the winter, the impact of missing sea ice is mostly felt in the atmosphere, said Jennifer Francis, a climate scientist at Rutgers University in New Brunswick, New Jersey.

“In places where sea ice has been lost, those areas of open water will put more heat into the atmosphere because the air is much colder than unfrozen sea water,” Francis said. “As winter sea ice disappears, areas of unusually warm air temperatures in the Arctic will expand. These are also areas of increased evaporation, and the resulting water vapor will contribute to increased cloudiness, which in winter, further warms the surface.”

From the National Snow and Ice Data Center:

This photograph from a March 27, 2015 NASA IceBridge flight shows a mixture of deformed, snow-covered, first-year sea ice floes, interspersed by open-water leads, brash ice and thin, snow-free nilas and young sea ice over the East Beaufort Sea. Nilas are thin sheets of smooth, level ice less than 10 centimeters (4 inches) thick and appear darkest when thin. Credit: NASA/Operation Ice Bridge.
This photograph from a March 27, 2015 NASA IceBridge flight shows a mixture of deformed, snow-covered, first-year sea ice floes, interspersed by open-water leads, brash ice and thin, snow-free nilas and young sea ice over the East Beaufort Sea. Nilas are thin sheets of smooth, level ice less than 10 centimeters (4 inches) thick and appear darkest when thin. Credit: NASA/Operation Ice Bridge.

Arctic sea ice was at a record low maximum extent for the second straight year, according to scientists at the National Snow and Ice Data Center (NSIDC) and NASA.

“I’ve never seen such a warm, crazy winter in the Arctic,” said NSIDC director Mark Serreze. “The heat was relentless.” Air temperatures over the Arctic Ocean for the months of December, January and February were 2 to 6 degrees Celsius (4 to 11 degrees Fahrenheit) above average in nearly every region.

Sea ice extent over the Arctic Ocean averaged 14.52 million square kilometers (5.607 million square miles) on March 24, beating last year’s record low of 14.54 million square kilometers (5.612 million square miles) on February 25. Unlike last year, the peak was later than average in the 37-year satellite record, setting up a shorter than average ice melt season for the coming spring and summer.

According to NSIDC, sea ice extent was below average throughout the Arctic, except in the Labrador Sea, Baffin Bay, and Hudson Bay. It was especially low in the Barents Sea. As noted by Ingrid Onarheim at the Bjerknes Centre for Climate Research in Bergen, Norway: “A decrease in Barents Sea ice extent for this winter was predicted from the influence of warm Atlantic waters from the Norwegian Sea.”

Scientists are watching extent in this area because it will help them understand how a slower Atlantic Meridional Overturning Circulation (AMOC) may affect Arctic sea ice. “Some studies suggest that decreased heat flux of warm Atlantic waters could lead to a recovery of all Arctic sea ice in the near future,” said NSIDC senior research scientist Julienne Stroeve. “I think it will have more of a winter impact and could lead to a temporary recovery of winter ice extent in the Barents and Kara seas.”

This year’s maximum extent is 1.12 million square kilometers (431,000 square miles) below the 1981 to 2010 average of 15.64 million square kilometers (6.04 million square miles) and 13,000 square kilometers (5,000 square miles) below the previous lowest maximum that occurred last year.

This late winter, ice extent growth in the Arctic has been sluggish. “Other than a brief spurt in late February, extent growth has been slow for the past six weeks,” said Walt Meier, a research scientist at the NASA Goddard Space Flight Center. Meier is an affiliate scientist at NSIDC and is part of NSIDC’s Arctic Sea Ice News and Analysis team.

Ice extent increases through autumn and winter, and the maximum typically occurs in mid March. Sea ice then retreats through spring and summer and shrinks to its smallest or minimum extent typically by mid September.

The September Arctic minimum began drawing attention in 2005 when it first shrank to a record low extent over the period of satellite observations. It broke the record again in 2007, and then again in 2012. The March Arctic maximum has typically received less attention. That changed last year when the maximum extent was the lowest in the satellite record.

“The Arctic is in crisis. Year by year, it’s slipping into a new state, and it’s hard to see how that won’t have an effect on weather throughout the Northern Hemisphere,” said Ted Scambos, NSIDC lead scientist.

NSIDC will release a full analysis of the winter season in early April, once monthly data are available for March.

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