Winter Sea Ice Fails to Recover, Down to Record Low

Apr 06, 2006
Winter Sea Ice Fails to Recover, Down to Record Low
March 2006 mean sea ice extent, indicated by the red dot, is 300,000 square kilometers (115,860 square miles) less than the 2005 record, and 1.2 million square kilometers (463,000 square miles) below the 1979-2000 mean.

Scientists at NSIDC announced that March 2006 shows the lowest Arctic winter sea ice extent since the beginning of the satellite record in 1979 (see Figures 1 and 2). Sea ice extent, or the area of ocean that is covered by at least 15 percent ice, was 14.5 million square kilometers (5.60 million square miles) for this March, as compared to 14.8 million square kilometers (5.72 million square miles) for March 2005, the previous record.

The Arctic sea ice shrinks during the summer and grows, or recovers, during the winter. The ice reaches its maximum extent during March, with a long-term (1979-2000) monthly mean extent of 15.7 million square kilometers (6.06 million square miles). Winter sea ice extent has begun to show a significant downward trend over the past four years.

However, the winter recovery trend is not as striking as the sea ice minimum trend (see the press release Sea Ice Decline Intensifies, 28 September 2005). Changes in the sea ice minimum extent are especially important because more of the sun's energy reaches Earth's surface during the Arctic summer than during the Arctic winter. Sea ice reflects much of the sun's radiation back into space, whereas dark ice-free ocean water absorbs more of the sun's energy. So, reduced sea ice during the sunnier summer months has more of an impact on the Arctic's overall energy balance than reduced ice in the winter.

The lower winter extents are still important, however, because they reflect the pattern of reduced sea ice that scientists have already seen. Low winter recovery means that the ice is freezing up later in the fall and growing at a slower pace in the winter.

Walt Meier of NSIDC notes, "Poor winter recovery of the sea ice leads to less new ice growth and thinner ice. The weaker the ice at the end of winter, the more easily it melts the following summer."

Source: National Snow and Ice Data Center

Explore further: An unmanned rocket exploded. So what?

add to favorites email to friend print save as pdf

Related Stories

The secret life of the sea trout

Oct 29, 2014

Jan G. Davidsen and his graduate students are spies. They use listening stations and special tags they attach to their subjects to track their movements. They follow their subjects winter and summer, day ...

Under Rainier's crater, a natural laboratory like no other

Oct 03, 2014

Counting all the ups and downs, he had climbed more than 15,000 feet to get here - past yawning crevasses and over cliffs where a single misstep could send a rope team tumbling. His party was pummeled by a lightning storm ...

Cyanide ice in Titan's atmosphere

Oct 01, 2014

Gigantic polar clouds of hydrogen cyanide roughly four times the area of the UK are part of the impressive atmospheric diversity of Titan, the largest moon of Saturn, a new study led by Leiden Observatory, ...

Recommended for you

An unmanned rocket exploded. So what?

2 hours ago

Sputnik was launched more than 50 years ago. Since then we have seen missions launched to Mercury, Mars and to all the planets within the solar system. We have sent a dozen men to the moon and many more to ...

When did galaxies settle down?

2 hours ago

Astronomers have long sought to understand exactly how the universe evolved from its earliest history to the cosmos we see around us in the present day. In particular, the way that galaxies form and develop ...

NASA image: Sunrise from the International Space Station

2 hours ago

NASA astronaut Reid Wiseman posted this image of a sunrise, captured from the International Space Station, to social media on Oct. 29, 2014. Wiseman wrote, "Not every day is easy. Yesterday was a tough one. ...

Copernicus operations secured until 2021

3 hours ago

In a landmark agreement for Europe's Copernicus programme, the European Commission and ESA have signed an Agreement of over €3 billion to manage and implement the Copernicus 'space component' between 2014 ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.