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Arctic sea ice extent breaks 2007 record low

Scattered ice floes are seen from the bridge of the USCGC Healy on August 20, 2012 northwest of Barrow, Alaska. Arctic sea ice fell to its lowest daily extent in the satellite record on Sunday, August 26, 2012.

Scattered ice floes are seen from the bridge of the USCGC Healy on August 20, 2012 northwest of Barrow, Alaska. Arctic sea ice fell to its lowest daily extent in the satellite record on Sunday, August 26, 2012.

PHOTO: U.S. Coast Guard

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.

Arctic sea ice cover melted to its lowest extent in the satellite record yesterday, breaking the previous record low observed in 2007. Sea ice extent fell to 4.10 million square kilometers (1.58 million square miles) on August 26, 2012. This was 70,000 square kilometers (27,000 square miles) below the September 18, 2007 daily extent of 4.17 million square kilometers (1.61 million square miles).

NSIDC scientist Walt Meier said, "By itself it's just a number, and occasionally records are going to get set. But in the context of what's happened in the last several years and throughout the satellite record, it's an indication that the Arctic sea ice cover is fundamentally changing."

According to NSIDC Director Mark Serreze, "The previous record, set in 2007, occurred because of near perfect summer weather for melting ice. Apart from one big storm in early August, weather patterns this year were unremarkable. The ice is so thin and weak now, it doesn't matter how the winds blow."

"The Arctic used to be dominated by multiyear ice, or ice that stayed around for several years," Meier said. "Now it's becoming more of a seasonal ice cover and large areas are now prone to melting out in summer."

With two to three weeks left in the melt season, NSIDC scientists anticipate that the minimum ice extent could fall even lower.

In 2007, Arctic sea ice extent reached an all-time low in the satellite record that began in 1979. Arctic sea ice follows an annual cycle of melting through the warm summer months and refreezing in the winter. While Arctic sea ice extent varies from year to year because of changeable weather conditions, ice extent has shown a dramatic overall decline over the past thirty years. The pronounced decline in summer Arctic sea ice over the last decade is considered a strong signal of long-term climate warming.

NSIDC will release a full analysis of the melt season in early October, once monthly data are available for September.

Arctic sea ice appears to have broken the 2007 record daily extent and is now the lowest in the satellite era. With two to three more weeks left in the melt season, sea ice continues to track below 2007 daily extents.

Please note that this is not an announcement of the sea ice minimum extent for 2012. NSIDC will release numbers for the 2012 daily minimum extent when it occurs. A full analysis of the melt season will be published in early October, once monthly data are available for September.

Overview of conditions

Figure 1. Arctic sea ice extent for August 26, 2012 (right) was 4.10 million square kilometers (1.58 million square miles), which was 70,000 square kilometers (27,000 square miles) below the September 18, 2007 daily extent of 4.17 million square kilometers (1.61 million square miles, left). The orange line shows the 1979 to 2000 median extent for that day. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data.


Credit: National Snow and Ice Data Center
High-resolution images: Figure 1a , Figure 1b

Arctic sea ice extent fell to 4.10 million square kilometers (1.58 million square miles) on August 26, 2012. This was 70,000 square kilometers (27,000 square miles) below the September 18, 2007 daily extent of 4.17 million square kilometers (1.61 million square miles).

Including this year, the six lowest ice extents in the satellite record have occurred in the last six years (2007 to 2012).

Conditions in context

Figure 2. The graph above shows Arctic sea ice extent as of August 26, 2012, along with daily ice extent data for 2007, the previous record low year, and 1980, the record high year. 2012 is shown in blue, 2007 in green, and 1980 in orange. The 1979 to 2000 average is in dark gray. The gray area around this average line shows the two standard deviation range of the data. The 1981 to 2010 average is in sky blue. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

 

After tracking near 2007 levels through July, the extent declined rapidly in early August. Since then, the loss rate has slowed some, averaging about 75,000 square kilometers (29,000 square miles) per day—equivalent to the size of the state of South Carolina. However, this is still much faster than the normal rate at this time of year of about 40,000 square kilometers per day (15,000 square miles).

Note that the date and extent of the 2007 minimum have changed since we originally posted in 2007; see our Frequently Asked Questions for more information.

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