Global polar sea ice area in September 2014 remained at or near climatological normal conditions (1979-2008). This situation has held true since early 2013 – a clear departure from conditions during the past 10+ years. Global sea ice area values consist of two components: Arctic and Antarctic sea ice. Conditions are quite different between these two regions: there is abundant Antarctic sea ice while Arctic sea ice remained well below normal again during 2014. I’ll discuss both regions below.
Arctic Sea Ice
According to the NSIDC, September 2014′s average extent was 5.28 million sq. km., a 1.24 million sq. km. below normal conditions. This value is the minimum for 2014 as less sunlight and colder fall temperatures now allow for melting ice. September 2014 sea ice extent continued a two-plus year-long trend of monthly mean below normal values. The deficit from normal was different each month during that time due to weather conditions overlaying longer term climate signals.
Sea ice anomalies at the edge of the pack are of interest. Laptev and East Siberian Sea ice, for instance, was lower than their respective normals this year while Beaufort Sea and Canadian Archipelago ice maintained higher ice extent this year than they did a few years ago. Arctic Basin ice extent was lower than its normal, but higher than it was during the late-2000s.
September 2014 average sea ice extent was the sixth lowest in the satellite record (post-1979). Figure 1 shows that the September linear rate of decline is 13.3% per decade (blue line) relative to the 1981 to 2012 mean, compared to 2.6% per decade decline for March through 2014. Summer ice is more affected from climate change than winter ice. Of note, the trend through September 2013 was 13.7%, so this year’s minimum, while historically significant, was not as bad as it was during recent years.
Figure 1 – Mean Sea Ice Extent for September: 1979-2014 [NSIDC].
Arctic Pictures and Graphs
The following graphic is a satellite representation of Arctic ice as of April 1st, 2014:
Figure 2 – UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20140401.
Compare that with the following graphic – a satellite representation of Arctic ice as of October 7th, 2014:
Figure 3 – UIUC Polar Research Group‘s Northern Hemispheric ice concentration (color contours) from 20141007. Recent snowfall is indicated by gray-scheme contours over land.
As described above, the 2014 melt season ended with the sixth lowest Arctic sea ice extent during the satellite era. Approximately 10 million sq. km. of sea ice melted again this year. That isn’t a record (11.5 million sq. km. melted in 2012), but that is a lot of melted ice.
Of greater importance is the overall health of the ice pack, which we can begin to ascertain by looking at the volume of ice, as in Figure 4:
Figure 4 – PIOMAS Arctic sea ice volume time series through September 2014.
This graph shows something unique: a recent resurgence of ice volume anomalies during the past 2-3 years. You can see that in 2011 and 2012, Arctic sea ice volume reached values below the 2nd standard deviation from normal – near -7000 and -8000 km^3. 2013 looked a bit better and 2014 looks better still: volume anomalies are back above the long-term trend line. While that isn’t enough to declare no problems exist in the Arctic, the situation certainly is different from it was just a couple of years ago. Put another way, these graphics show something quite different from the strident proclamations of doom from climate activists in early 2013 when holes and cracks were seen earlier than normal on Arctic sea ice. At the time, they wondered (too loudly at times) whether an ice-free summer was in our immediate future. I cautioned against such radical conclusions at the time and continue to do so now. While not healthy, Arctic sea ice isn’t in as bad a shape as some wanted to believe.
Arctic Sea Ice Extent
Take a look at September’s areal extent time series data:
Figure 5 – NSIDC Arctic sea ice extent time series through early Ocrtober 2014 (light blue line) compared with four recent years’ data, climatological norm (dark gray line) and +/-2 standard deviation envelope (light gray).
This figure puts 2014 into context against other recent winters. As you can see, Arctic sea ice extent was at or below the bottom of the negative 2nd standard deviation from the 1981-2012 mean during each of the past five years. The 2nd standard deviation envelope covers 95% of all observations. That means the past five years’ ice extents were extremely low compared to climatology. Thankfully, 2014 sea ice extent did not set another all-time record. This year’s values were within the 2nd standard deviation envelope and look similar to 2013’s.
Antarctic Pictures and Graphs
Here is a satellite representation of Antarctic sea ice conditions from April 2nd, 2014:
Figure 6 – UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20140402.
And here is the corresponding figure from October 7th, 2014:
Figure 7 – UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20141007.
Here we see evidence that the Antarctic is quite different from the Arctic. Instead of record minimums, Antarctic sea ice is recording record maximums. The April graphic begins the story: the Antarctic sea ice minimum value this year was quite high, so ice started from a different (higher) point than in recent decades. This new pattern evolved during the past few years and absent additional changes is likely to continue for the foreseeable future. With a head-start on ice extent, mid-winter ice grew to the largest extent on record: 20.03 million sq. km., 1.24 million sq. km. above the 1981 to 2010 average for September ice extent.
Figure 8 shows this situation in time series form:
Figure 8 – NSIDC Antarctic sea ice extent time series through early October 2014.
The big surge in extent in late September is all the more impressive because it set another all-time record for extent, as also happened in 2012 and 2013, as Figure 9 shows:
Figure 9 – Mean Antarctic Sea Ice Extent for September: 1979-2014 [NSIDC].
You’re eyes aren’t deceiving you: the Antarctic September sea ice extent trend is opposite that of the Arctic sea ice extent trend. The Antarctic trend is +1.3%/decade. The reason for this seeming discrepancy is rooted in atmospheric chemistry and dynamics (how and why the atmosphere moves the way it does) and ice dynamics. A reasonable person without polar expertise likely looks at Figures 1 and 9 and says, “I don’t see evidence of catastrophe here. I see something bad in one place and something good in another place.” For people without the time or inclination to invest in the layered nuances of climate, most activists come off sounding out of touch when they always preach gloom and doom. If climate change really were as clearly devastating as activists screamed it was, wouldn’t it be obvious in all these pictures and plots? Or, as I’ve commented at other places recently, do you really think people who are insecure about their jobs and savings even have the time for this kind of information?
Given the lack of climate policy development at a national or international level to date, Arctic conditions will likely continue to deteriorate for the foreseeable future. This is especially true when you consider that climate effects today are largely due to greenhouse gas concentrations from 30 years ago. It takes a long time for the additional radiative forcing to make its way through the entire climate system. The Arctic Ocean will soak up additional energy (heat) from the Sun due to lack of reflective sea ice each summer. Additional energy in the climate system creates cascading and nonlinear effects throughout the system. For instance, excess energy can push the Arctic Oscillation to a more negative phase, which allows anomalously cold air to pour south over Northern Hemisphere land masses while warm air moves over the Arctic during the winter. This in turn impacts weather patterns throughout the year (witness winter 2013-14 weather stories) across the mid-latitudes and prevents rapid ice growth where we want it.
More worrisome for the long-term is the heat that impacts land-based ice. As glaciers and ice sheets melt, sea-level rise occurs. Beyond the increasing rate of sea-level rise due to thermal expansion (excess energy, see above), storms have more water to push onshore as they move along coastlines. We can continue to react to these developments as we’ve mostly done so far and allocate billions of dollars in relief funds because of all the human infrastructure lining our coasts. Or we can be proactive, minimize future global effects, and reduce societal costs. The choice remains ours.