Arctic Sea Ice Minimum in 2013 is Sixth Lowest on Record: Comeback or Fluke?

The extent of the sea ice that covers the Arctic has officially reached its minimum--and it's surprisingly high. Due to an unusually cold summer in the northernmost latitudes, the Arctic sea minimum is the sixth lowest on record.

NASA regularly records the extent of the Arctic sea ice. Monitoring its extent is crucial for better understanding how the melting ice can impact our world. Researchers employ satellite imagery, submarine sonar and data collected from NASA's Operation IceBridge, an airborne survey of polar ice. Yet while researchers found that the extent of the ice stretched far further than previous years, its thickness was much less. In fact, scientists discovered that the ice thickness is as much as 50 percent thinner than it was in previous decades, going from an average of 12.5 feet in 1980 to 6.2 feet in recent years.

Stretching 1.32 million square miles, the sea ice is about half the average minimum extent from 1981 to 2010. That said, the current extent doesn't surprise scientists all that much.

"I was expecting that this year would be higher than last year," said Walt Meier, a glaciologist at NASA's Goddard Space Flight Center, in a news release. "There is always a tendency to have an uptick after an extreme low; in our satellite data, the Arctic sea ice has never set record low minimums in consecutive years."

This summer's minimum extent is still in line with the long-term downward trend of about 12 percent per decade since the late 1970s, a decline that has accelerated after 2007. Since weather conditions shift and change year per year, a higher extent doesn't mean that the overall trend is going up.

"The trend with decreasing sea ice is having a high-pressure area in the center of the Arctic, which compresses the ice pack into a smaller area and also results in clear skies, which enhances melting due to the sun," said Richard Cullather, an atmospheric scientist, in a news release. "This year, there was low pressure, so the cloudiness and the winds associated with the cyclones expanded the ice."

From now, the sea ice extent is likely to increase before beginning to melt again starting next summer. Exactly how far it will shrink, though, remains anyone's guess.

Want to see the sea ice extent for yourself? Check out the video below, courtesy of NASA and YouTube.