Arctic Sea Ice 2013: The 60% Rebound After the 2012 Record Low

In September 2013 a British newspaper headline declared "And now it's global COOLING!" after Arctic sea ice covered far more ocean than in the record-breaking melt of 2012. The rebound was real: the 2013 summer minimum was about 60 percent larger than the year before. But satellite records from NASA and the US National Snow and Ice Data Center (NSIDC) show what happened next, and why one cool summer did not turn the trend around.

Arctic sea ice: the 2012 record low and the 2013 rebound

Arctic sea ice grows every winter and shrinks every summer, reaching its smallest extent in September. On 16 September 2012 it fell to 3.41 million km², the lowest since satellite records began in 1979 and about half the average minimum of 1981–2010.

A year later the picture looked very different. The 2013 minimum, reached on 13 September, was 5.10 million km², roughly 1.7 million km² more ice than in 2012. NASA scientists put this down to the weather: spring and summer in the Arctic were 1 to 3 °C cooler than average, which delayed the melt season, and a series of cyclones brought clouds that shaded the ice from the sun.

The 60 percent headline and the 2007 "ice-free" forecast

The newspaper's 60 percent figure compared August 2012 with August 2013. The article also quoted scientists including Anastasios Tsonis of the University of Wisconsin-Milwaukee, the Greek-American climate researcher known for his work on how natural cycles in the Pacific and Atlantic oceans interact, and contrasted the rebound with a BBC report from December 2007.

That BBC story covered a modelling study by Wieslaw Maslowski of the US Naval Postgraduate School, presented at the American Geophysical Union meeting, which suggested the Arctic could be nearly free of summer ice by 2013. It was one of the most aggressive projections of its time. Most researchers, including the Intergovernmental Panel on Climate Change, expected ice-free summers decades later, and the 2013 ice proved the faster forecast wrong.

Why 2013 was still the sixth lowest on record

A big jump from a record low can still leave the ice well below normal. The 2013 minimum ranked as the sixth smallest in the satellite record, and the September 2013 average extent was more than 17 percent below the 1981–2010 average. NOAA's 2013 Arctic Report Card put the long-term decline of September ice at 13.7 percent per decade.

Thickness tells the same story. NASA reported that the average thickness of Arctic sea ice fell from 3.8 m in 1980 to about 1.9 m in recent years. Thick multiyear ice, which survives at least two summers and is typically 3 to 4 m thick, has declined fastest; most of the ice now is thinner first-year ice, 1 to 2 m thick, which melts out more easily. As NASA Goddard's Walt Meier noted at the time, the sea ice had never set record lows in consecutive years, so a rebound after 2012 was expected.

Arctic sea ice since 2013

More than a decade of data since then has settled the question. The 2012 record low still stands, yet the ice has not returned to the levels of the 1980s and 1990s. In 2025 the summer minimum, reached on 10 September, was 4.60 million km², tied with 2008 for the tenth lowest on record, and smaller than in 2013. According to Meier, now at NSIDC, every Arctic minimum for the past 19 years has been below the levels seen before 2007.

The lesson of 2013 is about time scales. Weather can add or remove a million square kilometres of ice in a single summer; climate is the trend that shows through when you line up all the Septembers since 1979.

Explore more: another misleading Arctic image caption; a regional study of past summer warmth.

Related reading:

• Antarctic Sea Ice: Why the Old Growth Story Needs Updating
• Lake Hodgson: Microbial Evidence from Antarctic Sediments
• Iain Stewart Explores Ice in Earth: The Power of the Planet
• Planet Earth: A Short Landscape Montage
• Eisriesenwelt: The Ice Cavern inside an Austrian Mountain
• The Arctic Light: Lofoten’s Long Spring Twilight

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