NSIDC: Arctic Sea Ice Hits Annual Bottom

September 21, 2013

nsidc0913

National Snow and Ice Data Center:

On September 13, Arctic sea ice reached its likely minimum extent for 2013. The minimum ice extent was the sixth lowest* in the satellite record, and reinforces the long-term downward trend in Arctic ice extent. Sea ice extent will now begin its seasonal increase through autumn and winter. Meanwhile, in the Antarctic, sea ice extent reached a record high on September 18, tied with last year’s maximum.

Please note that this is a preliminary announcement. Changing winds could still push ice floes together, reducing ice extent further. NSIDC scientists will release a full analysis of the melt season in early October, once monthly data are available for September.

John Abraham and Dana Nuccitellli in the Guardian:

As Suzanne Goldenberg reported in The Guardian yesterday, Arctic sea ice appears to have reached its annual minimum extent, at approximately 5.1 million square kilometers. This is the 6th-lowest extent since the satellite record began in 1979.

But in fact, scientists have also reconstructed Arctic sea ice extent data much further into the past. For example, Drs. Walsh & Chapman from the University of Illinois have estimated sea ice extent as far back as the year 1870 using a vast array of data (for example, records kept by the Danish Meteorological Institute and Norwegian Polar Institute, and reports made from ocean vessels). While climate contrarians will sometimes try to argue that Arctic sea ice extent may have reached similar lows to today’s in the 1920s or 1930s–1940s, the data compiled by Walsh & Chapman tell a very different story.

Average July through September Arctic sea ice extent 1870–2008 from the University of Illinois (Walsh & Chapman 2001 updated to 2008) and observational data from NSIDC for 2009–2013

Going back even further in time, a study published in the journal Nature in 2011 used a combination of Arctic ice core, tree ring, and lake sediment data to reconstruct Arctic conditions going back 1,450 years. The result is shown below.

study published in 2010 by 18 leading Arctic experts examined Arctic records throughout geologic history and concluded,

“The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.”

Thus the scientific data and literature indicate that this year’s minimum Arctic sea ice extent is not just the 6th-lowest in the past 34 years, but most likely the 6th-lowest in at least the past few thousand years.

The current Arctic sea ice decline is remarkably rapid, and often referred to as a “death spiral.” As Dr. Julienne Stroeve from the National Snow and Ice Data Center (NSIDC) told The Guardian,

“Overall, the Arctic has lost about 40% of its sea ice cover since 1980. Most scientists believe the Arctic could be entirely ice-free in the summers by the middle of the century – if not sooner.”

The Arctic ice has also been thinning rapidly, losing approximately 75 percent of its summer volume since 1980.

So what to make of the many claims over the past two weeks that the Arctic sea ice is “recovering”? These counter-factual arguments primarilyoriginated from David Rose at the Mail on Sunday, whose article Bob Ward accurately described as containing “embarrassing errors” to the extent of being a “humiliation” for the Mail on Sunday.

Unfortunately many other media outlets (the Telegraph and Fox News, for example) assumed David Rose to be an accurate source of climate information – despite his long track record of getting nearly everything he says with regards to climate change wrong – and echoed Rose’s embarrassing errors. Rush Limbaugh engaged in what Graham Readfearn has described as ‘a bad game of Chinese whispers,’amplifying Rose’s errors further by wrongly asserting,

“Now, if you haven’t heard this, the ice at the North Pole, arctic ice, is at a record amount this early in the post-summer season.”

Sadly, the climate contrarian media echo chamber (which has beenworking overtime in advance of the publication of the next IPCC report) has taken factually inaccurate reporting and twisted reality even further, asserting that the 6th-lowest Arctic sea ice extent in millennia is “a record amount.”

In reality, because last year’s Arctic sea ice minimum shattered the previous record low, and the ice had declined the previous two years as well, statistically speaking a short-term ‘recovery’ this year was likely to happen. In fact, it was predicted by most Arctic climate experts.

However, when we examine the long-term trend in the Arctic sea ice extent, it becomes clear that contrarian declarations of a “recovery” are based on viewing the data through Rose-colored glasses.

September Arctic sea ice extent data since 1980 from NSIDC (blue diamonds). “Recovery” years, meaning years when the sea ice extent is greater than the previous year, are highlighted in red to illustrate how climate contrarians view the data.

Perceptions of the Arctic can be used as a litmus test to distinguish between skepticism and denial. There is simply no question that Arctic sea ice is in the midst of a rapid decline, at rates and to minimum extents unseen in millennia. The body of scientific research also clearly shows that most of that rapid decline is due to human influences on the climate. There’s simply no sense in denying the rapid human-caused decline of Arctic sea ice; doing so is a clear indicator of a lack of skepticism and abundance of denial.

 

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5 Responses to “NSIDC: Arctic Sea Ice Hits Annual Bottom”

  1. Gingerbaker Says:

    Is the reason we still measure ice extent, when we can now measure ice volume – which would seem to me to be much more salient information – simply because we have ice extent records which go back further than volume data?

    Now that we know that AGW is putting vast amounts of heat into various lower depth strata of the ocean, and there is data demonstrating that Antarctic and Arctic ice sheets are being melted from below, is it even wise to talk about ice extent anymore?

  2. JW Rebel Says:

    I have no expertise, but the extent says something about how big the area is reflecting radiation (ice) as oppossed to absorbing radiation (ocean), whereas the volume/thickness says a lot about the trend and likely future extent — not to mention how hard/easy it is to operate a snow-mobile or hike across as a polar bear. Even if the ice is only an inch thick, it is still reflective.

    • greenman3610 Says:

      since the most important heat that is melting ice comes from below, thin ice is more vulnerable. thin ice is also more vulnerable to getting broken up by storms and cyclones, which again makes it more subject to melt.

  3. astrostevo Says:

    “..asserting that the 6th-lowest Arctic sea ice extent in millennia is “a record amount.asserting that the 6th-lowest Arctic sea ice extent in millennia is “a record amount.”

    Well, I suppose at a stretch you could claim it is *some* sort of record – just NOT the type I gather they’re meaning.


  4. […] 2013/09/21: PSinclair: NSIDC: Arctic Sea Ice Hits Annual Bottom […]


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